OERadio

MeshCore for Children and Teenagers: What Is Allowed in Austria

Michael | OE8YML — Fri, 02 Oct 2026 18:00:00 GMT

A ten-year-old plugs a 30-euro board into a laptop, clicks "Flash" in the browser, pairs a phone over Bluetooth and a minute later sends a message that travels across the valley via three repeaters. No mobile network, no SIM, no contract. This is not a vision of the future. It is an afternoon with MeshCore.

Which brings the question parents, teachers and youth leaders ask immediately: is the child even allowed to do this? The short answer is yes, with no exam and no age limit. The long answer is more interesting, because radio law is not the problem here at all. The pitfalls sit elsewhere.

The short version

MeshCore runs on 869.4 to 869.65 MHz, a generally authorised frequency range. No licence, no exam, no minimum age.
That is the decisive difference from amateur radio: there a licence starts at 14, here there is none at all.
The real risk is not the transmitter but location sharing. It is optional and should stay off for children.
Under 14 the supervising adult is liable for damage, from 14 the child is liable personally.
The only practical age limit comes from the app store: an Apple ID or Google account requires 14 in Austria. Via a laptop it works below that too.
MeshCore is not an emergency service. 112 remains 112.

Why MeshCore sits in a completely different legal drawer

oeradio.at is mostly about amateur radio, and there the situation for young people is clearly regulated. The licence requires the completed 14th year of life, as set out in § 38 para. 1 no. 1 TKG 2021. Anyone not fully capable of acting also needs a declaration from a fully capable person assuming liability for the fees. The exam itself has no minimum age, but the callsign still only comes at 14. Details are in our overview of Austrian amateur radio legislation.

What is allowed below 14 is often told more generously than the law allows. "Operating under supervision" appears in no ordinance. The TKG knows exactly one case: short-term operation of a club station at an international amateur radio event, directly supervised by a licensed amateur and notified in writing to the Fernmeldebüro two weeks in advance (§ 28 para. 2 no. 2 and para. 3). An afternoon in the neighbour's shack is not that.

None of that applies to MeshCore. Not a single sentence. MeshCore is not amateur radio; it runs in the SRD range, short range devices. Legally that is an entirely different drawer, and amateur radio law simply does not reach it.

The chain looks like this. The Telecommunications Act 2021 (TKG 2021) states in § 28 para. 1 that building and operating a radio installation is permitted only, among other routes, "within the technical conditions of an ordinance under para. 10". Para. 10 empowers the responsible minister to issue exactly that ordinance for operation "without individual frequency assignment or operating licence (general authorisation)". Since 15 April 2026 that ordinance is the Generelle-Funkanlagen-Bewilligungsverordnung 2026 (GenBV 2026), Federal Law Gazette II No. 93/2026. It grants the authorisation among others for radio equipment that may be operated in EU-harmonised frequency ranges.

Translated: the legislator granted the permission once, in bulk, for everyone. Nobody applies, nobody gets a callsign, nobody is registered. And because there is no personal licence, there is no person who would have to meet a minimum age.

The numbers that matter

The European version of the rules sits in ERC Recommendation 70-03 and in the EU implementing decision on short range devices. For the range MeshCore uses in Europe:

869.4 to 869.65 MHz: maximum 500 mW ERP, maximum 10 % duty cycle. This is MeshCore's playground.
For comparison, 865 to 868 MHz: only 25 mW ERP and 1 % duty cycle.
And 863 to 870 MHz in general: 25 mW ERP at 0.1 % duty cycle.

The MeshCore standard for Austria is the preset EU/UK (Narrow): 869.618 MHz, bandwidth 62.5 kHz, spreading factor 8, coding rate 8, transmit power up to 22 dBm. Every Austrian node uses these settings, otherwise they cannot hear each other. The community site meshcore.at currently lists more than 300 active nodes.

Two things worth explaining to a child, because they are the only real technical obligations:

500 mW ERP includes antenna gain. Plug in a 6 dBi antenna and the transmit power has to come down accordingly. In practice: stay away from maximum power when a good antenna is attached.
10 % duty cycle per hour per device. Normal chat traffic stays well below that. It only becomes a problem when someone builds automated continuous transmissions.

A LoRa node is manageable: board, antenna, enclosure, power. Exactly that makes it such a good first project. (Photo: Fabian Horst, CC BY-SA 4.0, Wikimedia Commons)

Video tip: from unboxing to the first node, step by step.

https://www.youtube.com/watch?v=yXf5fmceUuA

From what age exactly? Three answers

The question sounds like it wants a number, but it has three answers depending on what you look at.

Transmitting and receiving: no limit. In the whole Telecommunications Act 2021 the word "Lebensjahr" (year of life) appears exactly once, and that is for amateur radio. For 869 MHz no age appears anywhere. GenBV 2026 likewise knows only devices, not people.
Buying the device: from about seven. Children between 7 and 14 may conclude small transactions themselves under the pocket-money provision (§ 170 para. 3 ABGB), effective once they have paid. A 30-euro board out of pocket money qualifies. A 300-euro solar station does not.
Installing the app: effectively 14. An Apple ID or Google account requires 14 in Austria. Below that it runs through Family Sharing or Family Link, that is, through the parents' account.

So the 14 does not come from radio law but from the app store. MeshCore itself is rated for every age: 4+ on Apple, "Everyone" on Google Play.

And there is a route with no account at all. The companion app runs not only on a phone but also as a program for Windows, macOS and Linux. Flashing happens in the browser anyway. A child under 14 can therefore operate the node over USB from a laptop without anyone creating a store account. For schools that is usually the simpler path.

What matters when buying: the CE mark

The general authorisation comes with a condition that is easy to miss: it applies to radio equipment complying with the Radio Equipment Market Surveillance Act (FMaG 2016). So the device needs proper CE conformity, and its construction must restrict operation to the permitted parameters.

In practice that means a board from a reputable dealer with CE marking is unproblematic. A no-name module straight from the Far East that can be tuned to arbitrary frequencies is a grey area children should be spared. The price difference is about ten euros; the risk ends up with the supervising adult.

Typical entry-level hardware costs between 25 and 80 euros. Flashing happens through a web flasher in the browser, with nothing to install. Anyone who prefers a soldering iron will find the more elaborate route in our LoRa gateway article.

No soldering iron needed for the first step. For the second project, definitely. (Photo: Dbrgn, CC BY-SA 4.0, Wikimedia Commons)

Location is the real topic

Here it gets serious, and here radio law is finally out of the picture.

A MeshCore node periodically sends out an advert: name, position and public key. The advert can be limited to the immediate area or flooded across the whole network. The position is optional; it is not set automatically but entered deliberately.

For a repeater on a mountain that makes sense and is wanted, otherwise the map cannot find it. For a child carrying a node around in a backpack it is the opposite of sensible. A flooded advert with a real name and coordinates is a publicly readable location report, for anyone with a receiver in range.

Three rules you set once and can then forget:

No position on mobile nodes. Position only on fixed repeaters, and even there not pinpointed on the child's bedroom window.
No real name in the node name. "Max M., Villach" is bad. "OE8-Node-17" is good. Repeaters may and should carry place names; personal nodes should not.
No address, no school, no club name in the profile text.

A node lands on public maps by itself the moment it sends an advert. Nobody puts it there, and nobody can remove it for you. Consent is therefore the wrong lever; the right one is avoidance: location sharing off, name without a real name, without a school and without an address. What the node does not transmit appears on no map.

Data protection law does have an age limit, just elsewhere: under § 4 para. 4 of the Austrian Data Protection Act (DSG) a child can only give valid consent to the processing of its data in information society services from the completed 14th year of life; below that the legal guardians must consent. That covers everything the child signs up to: app store, forum, Discord, Telegram. Transmitting on a licence-free band is not such a service, because there is nobody to give consent to.

Who is actually reading?

MeshCore encrypts. That is the second big difference from amateur radio, where encryption is forbidden. In the SRD range it is allowed, and MeshCore uses it.

Direct messages are end-to-end encrypted. The shared key is derived through an X25519 key exchange from your own private key and the other party's public key. Repeaters in between forward ciphertext only; they cannot read along.
Public channels are encrypted too, but with a key every MeshCore device knows out of the box. That is not confidentiality, that is noise suppression. Whatever goes into the #austria channel is read by half the country.

A child needs to understand this distinction before switching on the first node. The rule of thumb is simple and sticks fast: everything in a channel is as public as a notice board. Only a direct message to a specific contact is private.

For completeness: the end-to-end encryption is not flawless either. MeshCore uses AES-128 in ECB mode, and ECB leaks patterns across repeated blocks. Entirely sufficient for teenage chat, not for secrets. Anyone with something confidential to discuss uses Signal, not the mesh.

Listening, forwarding, logging: where the line runs

A mesh node does something that by definition sounds like handling other people's messages: it accepts packets from others and passes them on. Is that interception?

No, and the law says so explicitly. § 161 para. 3 TKG 2021 prohibits "listening in on, intercepting, recording, capturing or otherwise monitoring messages and the associated traffic and location data, as well as passing on information about them, by persons other than a user without the consent of all users involved". The same paragraph expressly exempts "technical storage necessary for forwarding a message". That is precisely what a repeater does. Store and forward is permitted.

What is not permitted: systematically recording, analysing and publishing the traffic. Build a node that logs everything and puts the logs online and you leave the exemption. In criminal law § 119 StGB then comes into play, violation of telecommunications secrecy. Using a device to obtain knowledge of the content of a message not intended for you risks up to two years' imprisonment. Prosecution requires authorisation from the injured party, but that is not something to rely on.

Listening and passing on are two different things, and the law treats them separately. Recording, making available or publishing a message "not intended for" the person doing it falls under § 120 para. 2a StGB: up to three months' imprisonment or 180 daily rates, again only on authorisation of the injured party. Both provisions share the same precondition, namely that the message was not intended for the reader. On a public channel with a known key it very much was, so that channel falls outside both offences. Anyone recording other people's direct messages falls under both.

Spelled out three ways:

Reading the public channel: no offence. The key sits in every device, every participant is an addressee. That is the purpose of a public channel.
Breaking into direct messages or other people's private channels: § 119 StGB, up to two years, only on authorisation of the injured party.
Passing on or publishing other people's message contents: § 120 para. 2a StGB, up to three months or 180 daily rates, only on authorisation of the injured party.

For practice with children that means two things. First: running a repeater is entirely fine and in fact welcome. Second: reading the public channel is allowed; carrying what you read there any further is a matter of decency before it becomes one of law.

Liability: the age of 14 returns through the back door

Radio law has no minimum age. Civil law does, at exactly the same point as amateur radio.

Under 14 children lack tortious capacity. If they cause damage, § 1309 ABGB makes the supervising person liable, but only where the duty of supervision was culpably breached and that breach caused the damage. The extent of supervision depends on the child's age, characteristics and development.
From 14 minors have tortious capacity and are liable personally, with their own assets.
14 is also where criminal responsibility begins. Below that, a child cannot be prosecuted.

What can actually go wrong with a 30-euro board? Realistically, little. A node on the balcony causes no damage. It becomes relevant in two situations: when someone mounts an antenna on a roof and breaks something, and when something happens in the chat.

The latter is the more common case. A mesh network is a chat, and in chats what happens is what happens in chats. § 107c StGB criminalises continued harassment by means of telecommunications, colloquially cyberbullying: up to one year's imprisonment or 720 daily rates, up to three years where consequences are severe. The fact that the network is technically decentralised and nobody operates it changes nothing. A public channel is a public space.

MeshCore is not an emergency service

This point gets its own section because it is the only one in this article where a misunderstanding can do real harm.

MeshCore is not an emergency communications system. There is no operator, no availability guarantee, no control room listening, and no obligation on anyone to forward a message. Whether a repeater is up depends on whether somebody else kept their solar panel clean. That is the charm of the system and at the same time its limit.

Anyone discussing mesh with children should write the sentence down anyway, because the temptation is strong: "radio without a mobile network" sounds a lot like a lifeline to a child. In an emergency it is 112, and if there is no network it is still 112, because emergency calls go through any available network, even without your own SIM. The mesh is a supplement, never a replacement. Anyone with genuine emergency communications interest sooner or later arrives at amateur radio, and that is a good development.

Video tip: a home-built repeater on 868 MHz, including enclosure and power supply.

https://www.youtube.com/watch?v=aQTysCO3k4o

In school and in the youth group

For schools and youth groups MeshCore is almost too well suited to be true: no application, no fee, no exam, hardware in the price range of a pocket calculator, and at the end a network the group built itself.

What to settle beforehand:

Mounting on the building is the school authority's business, not the teacher's. A node on a window sill is a different matter from an antenna on the roof.
The duty of supervision remains. A mesh project is lessons, not a free pass for unsupervised chatting.
Agree node names in advance. School abbreviation plus number, no pupil names. Five minutes of clarity saves later discussions.
The public channel is public. That sentence belongs on the board before the first device is switched on.

As a project format it works well because it can be staged: first lesson flashing and pairing, second lesson measuring range, third lesson comparing antennas, fourth lesson planning a repeater. How well radio carries as a school topic was shown by the activity days at HTL Villach and by Funkparcours.

Comparison: what may a child use?

MeshCore (869 MHz): generally authorised, no minimum age, no exam, encryption allowed, text messages. Range 1 to 20 km directly depending on terrain, considerably further via repeaters.
Meshtastic (868 MHz): legally the same drawer, different firmware, different network. Both worlds coexist in Austria, see our practical article and the Meshmap.
PMR446 and CB radio: also licence-free and without an age limit, but voice instead of text and far less range. The three-way comparison puts that in context.
Amateur radio: the exam can be taken at any age, your own callsign comes at 14. Below that the law provides only the narrow case of a supervised club station. In exchange: high power, worldwide range and dedicated frequencies. Which class is good for what is in the licence class comparison.
MeshCom: the amateur radio variant of the mesh idea and therefore licensed, see MeshCom vs. Meshtastic.

The honest assessment: MeshCore is the lowest-threshold entry into radio available right now. It is not a replacement for amateur radio but the ramp leading to it. A child who understands why a node on a hill beats ten extra watts has already learned the most important lesson in radio.

The checklist for parents

Device from a reputable dealer with CE marking, no grey imports.
Preset EU/UK (Narrow), 869.618 MHz, transmit power no higher than needed.
Location sharing off as long as the node is mobile.
Node name without a real name, without an address, without a school.
Explain once together: channel is public, direct message is private.
Explain what is open and what is not: anyone may read the public channel, that is its purpose. Breaking into other people's direct messages is a criminal offence. And what you read in the public channel you do not carry further, which is a matter of decency before it becomes one of law.
State once clearly: in an emergency it is 112, not the mesh.
For roof mounting: the parents do that, not the child.

Conclusion

MeshCore is permitted for children and teenagers in Austria without an age limit. There is no minimum age, no exam and no notification duty, because the legislator granted the permission in bulk through GenBV 2026. Buy a compliant device, use the standard preset, and you stay inside the limits without having to think about it.

Attention belongs elsewhere. Location sharing is the one setting to make deliberately. The difference between public channel and direct message is the one concept a child has to grasp. And liability passes to the child at 14, before that it rests with the supervising adult.

That sounds like a lot, but it is a ten-minute conversation and three checkboxes in the settings. What remains is a hobby packing technology, geography, physics and a bit of neighbourhood into a single device that fits in a pocket. More than 300 nodes are currently active in Austria. One of them could be your child's.

73 – your oeradio.at editorial team

Sources and further reading

Correction notice

Correction of 3 October 2026: the recommendation about public maps was based on consent under § 4 para. 4 DSG, which does not apply there, because transmitting on a licence-free band is not an information society service. The age statement for amateur radio was too terse: the exam can be taken at any age, only your own callsign requires 14 years. Both passages have been corrected. § 120 para. 2a StGB has been added, together with the clarification that reading a public channel with a known key falls under neither § 119 nor § 120 StGB. The conclusion now says "without an age limit" instead of "fully permitted", because CE conformity, 500 mW ERP and a 10 % duty cycle are very much limits.

Addendum of 3 October 2026: a full-text re-check showed that the phrase "below that you operate under supervision" was too broad. No general rule of that kind exists in either TKG 2021 or the Amateurfunkverordnung; the law knows only the supervised club station at international events (§ 28 para. 2 no. 2). That passage has been made precise. Newly added is the section "From what age exactly?" with the pocket-money provision and the effective app-store limit of 14. The text now also says "capable of acting" instead of "legally capable", which is the term the TKG uses.

Image credits

Home-built LoRa gateway: Fabian Horst, CC BY-SA 4.0, Wikimedia Commons
Soldering stations in a hackerspace: Dbrgn, CC BY-SA 4.0, Wikimedia Commons

Videos: ShotokuTech, AW Services. Embedded via YouTube; rights remain with the respective channels.

Transparency Notice

This article was researched and written with the assistance of AI (Claude, Anthropic). The title image was created with AI (ChatGPT, OpenAI). The editorial team has reviewed and edited all content. It does not replace legal advice: laws and ordinances change, and assessment in an individual case rests with the competent authorities, for radio matters the Fernmeldebüro. Despite careful review, occasional inaccuracies may occur — we welcome corrections via email to kontakt@oeradio.at.

Der Beitrag MeshCore for Children and Teenagers: What Is Allowed in Austria erschien zuerst auf OERadio.

Antennas and Tenancy Law in Austria: Who Has to Consent, and How Do You Get It?

Michael | OE8YML — Mon, 28 Sep 2026 07:00:00 GMT

Most antenna problems in multi-party buildings are not antenna problems. They are jurisdiction problems. Which antenna physically fits into a flat, and what invisibility costs in signal, is covered in stealth antennas for apartments and HOA. This article is about the other half: who has to consent, what happens when nobody answers, how a notification should be worded so the deadlines work for you, and where to go when the answer is no.

That is not legal decoration, it is the part where the project actually succeeds or fails. And it is worth knowing, because Austrian law is friendlier at one decisive point than most people assume: silence can mean consent.

How many people this affects

According to the micro-census housing survey by Statistics Austria, 78 per cent of private households in Vienna live in rented accommodation, sublets included. Across Austria, 36 per cent of households live in owner-occupied houses. For radio amateurs that means the majority have no roof of their own to decide over.

Austria has no general antenna ban. It also has no explicit right to a transmitting antenna. What it does have are three separate layers that get mixed up all the time.

Three layers that have nothing to do with each other

Amateur radio law: your licence allows you to operate a station. It says nothing about whether you may drill into somebody else's façade. What the licensing rules do and do not cover is in our overview of Austrian amateur radio legislation.
Private law: the lease, the Tenancy Act, the Condominium Act. This is where it is decided whether the landlord or the co-owners get a say.
Public building law: the building code of the respective province. It does not care who owns the house, only about size, location and townscape.

All three can say no independently. An antenna that is permit-free under the building code can still be refused by the landlord, and an antenna approved by the landlord can be inadmissible in a protection zone.

When all three layers cooperate, it looks like this. Rooftop antennas in Bad Ischl, Upper Austria. (Photo: P e z i, CC BY-SA 3.0, via Wikimedia Commons)

Tenants: § 9 MRG and the two-month deadline

The central provision is § 9 MRG, alterations by the principal tenant. Its mechanism is the most useful sentence in the whole of housing law for radio amateurs: you notify the alteration in writing, and if the landlord does not object within two months of receiving the notification, his consent is deemed given.

If he does object, that is not the end. He may refuse only if one of the requirements of § 9 para 1 is not met. Seven points are listed there, among them that the alteration corresponds to the state of the art, serves an important interest of the tenant and, under no 5, gives no cause to fear an impairment of legitimate interests of the landlord or of other tenants. Case law places the burden of proving such an impairment on the landlord, not on you.

The catch we ourselves got wrong

§ 9 para 2 MRG lists alterations for which the requirements are deemed satisfied by law. No 5 explicitly mentions antennas, and this is where it is often read too generously. The wording covers the installation of antennas and other equipment necessary according to the state of the art for radio and television reception and for multimedia services, provided that connecting to an existing installation is not possible or not reasonable.

That is a reception privilege. An amateur radio antenna used for transmitting does not fall under it. It has to take the general route via para 1, that is via the important interest and the balancing test. An earlier version of this article said the reasoning from the satellite dish cases could be transferred in principle. That is too simple, and the distinction matters when a property manager replies with the statute in hand.

The good news: the two-month deadline in para 1 still applies. It does not depend on the privilege, it depends on a proper notification.

Restoration

For alterations not covered by para 2, the landlord may under para 3 make his consent conditional on you restoring the previous condition at the end of the tenancy. For a clamp mount on a balcony railing that is a non-issue, for a façade penetration it is not. Offering the restoration yourself takes the edge off the conversation.

The crucial caveat: does § 9 apply at all?

§ 9 sits in the full application area of the Tenancy Act. Simplified: full application covers flats in buildings with a building permit issued before 1 July 1953, and for condominium flats before 9 May 1945. Privately financed new construction based on a permit issued after 30 June 1953 falls under partial application per § 1 para 4 MRG, where only selected provisions apply, for instance on fixed terms, termination protection and succession rights.

For the antenna this means: in a new building you cannot rely on § 9 and its deemed consent. What counts then is the lease, plus general civil law. So before you send off a notification with a calculated deadline, check the year of construction and read the contract. In a Gründerzeit flat you are in a considerably better position than in a 2015 new build, and this is the one point where an old building is a legal advantage.

Condominiums: § 16 WEG

Owners of a condominium flat have a free hand within their own four walls. As soon as common parts are affected, meaning façade, roof, external wall and as a rule the balcony parapet too, § 16 para 2 WEG 2002 applies.

The change must not damage the building or impair the legitimate interests of the other owners, in particular not the external appearance, and must not create safety risks.
If common parts are used, the change must either be customary or serve an important interest of the owner.
Where impairment is possible, you need the consent of all other owners. If it is withheld, the non-contentious court can replace it.

And the trap most people walk into: the deemed-consent rule introduced by the 2022 amendment in § 16 para 5, silence within two months counting as consent, only covers privileged projects. The list includes accessible design, charging stations for electric vehicles, photovoltaics including balcony systems, harmoniously integrated shading and burglar-resistant doors. Antennas are not among them. In a condominium, silence does not work for you, unlike for the old-building tenant.

Practical consequence: in a condominium the antenna that touches no common parts at all is strategically far superior. Free-standing on your own balcony, clamp mounted, no drilling, no projection beyond the building line.

What the courts say

The relevant case law almost all concerns satellite dishes, and it is still useful because it shows the lines of the balancing test. In decision 5 Ob 199/03f of 21 October 2003 the Austrian Supreme Court clarified several points:

In the light of Article 10 ECHR, the right to use a satellite dish is to be granted to everyone in principle, including within a tenancy.
An existing cable connection alone is not a reason to refuse the antenna.
§ 9 MRG, however, confers no right to a particular mounting location. The landlord may insist on a reasonable alternative.
The burden of proving an impairment of legitimate interests under § 9 para 1 no 5 lies with the landlord.

Honestly classified: the ECHR argument carries further for reception than for transmission. Freedom of information protects access to information, not your own emissions. Anyone arguing with this case law should therefore emphasise the transferable part, namely the balancing method and the allocation of the burden of proof, and not claim there is a fundamental right to your own Yagi.

The strongest argument usually already hangs on your own façade: where satellite dishes are tolerated, a smaller antenna is hard to portray as unreasonable. (Example photo from Poland: Krzysztof Popławski, CC BY-SA 4.0, via Wikimedia Commons)

Building codes: nine provinces, nine answers

Building law is provincial law, and the differences are larger than the often quoted two-metre rule suggests. Three documented examples:

Province	Rule
Vienna	§ 62a para 1 no 24 of the building code: antenna, radio, solar thermal and parabolic installations are permit-free, outside protected green land, protection zones and areas under a building freeze. Inside a protection zone they do require a permit, and the townscape remains the yardstick.
Upper Austria	Antenna installations over three metres in height including the mast, measured from the base point, require a building permit in residential, village, core and mixed zones. In other zoning categories, such as commercial areas or green land, they are merely notifiable.
Lower Austria	A free-standing antenna mast requires a permit as the erection of a structure, and so does fixing a mast to a building as an alteration. Antennas without a mast are considerably simpler.

For the remaining provinces the same logic applies in different packaging: small antennas attached to the building without significant projection are usually free, free-standing masts and anything that shapes the townscape require approval. Asking the municipal building authority costs nothing, often takes one phone call, and is worth its weight in gold if there is a dispute later. If you intend to build properly from the start, the technical side is in towers and masts.

The template letter

A notification under § 9 MRG is not a form, it merely has to arrive and describe comprehensibly what you intend to do. That is exactly where most attempts fail, because they stay vague. This text covers what it needs to cover and starts the clock:

Subject: Notification of an alteration pursuant to § 9 MRG, flat no 12, Musterstraße 1

Dear Sir or Madam,
I hereby notify you of the planned installation of a receiving and transmitting antenna for the amateur radio service on my balcony.

Design: circular loop antenna, 90 cm in diameter, total height including tripod 1.6 m, free-standing or attached to the railing with a screw clamp. No drilling into the façade, parapet or masonry. The antenna cable is routed through a flat window feed-through without any structural alteration. The antenna does not project beyond the balcony parapet and is no more visible from the street than the existing satellite dishes in the building. A sketch and a photograph of the planned situation are enclosed.

I operate the amateur radio service on the basis of an official licence, call sign OE0XYZ. Operation uses low power, and the relevant technical standards on earthing and interference minimisation are observed.

I undertake to remove the antenna without trace at the end of the tenancy and to bear any damage arising from the installation. My liability insurance covers damage caused by the installation and I can provide confirmation.

Should you have objections, I ask for written notice within two months of receipt of this letter. I am happy to answer questions or arrange an on-site appointment.

Five things make this letter work. Its arrival is provable, so send it by registered post or with proof of delivery. It states dimensions instead of categories, because "loop antenna, 90 cm" triggers less resistance than "shortwave antenna". It says explicitly what will not happen, namely drilling. It removes two fears from the landlord, restoration and liability. And it mentions the deadline without threatening.

What does not belong in the letter: decibels, band plans, power levels. And no claim that there is a statutory right to the antenna. Come on too strong and you get a written no, and a written no is much harder to undo than a hesitant maybe.

What others in exactly this situation are working with

Before it comes to a dispute, a realistic look at what a low-approval solution actually achieves helps. Not to lower expectations, but because a landlord consents much more readily once he sees what is being discussed: a 90-centimetre object on a balcony.

https://www.youtube.com/watch?v=AD_G_sMWlHM

4,000 kilometres on JS8Call with a magnetic loop from a balcony. Exactly the antenna described in the notification to the landlord. (Dilettant45, in German)

https://www.youtube.com/watch?v=hPp2N8svP9Q

A balcony antenna in everyday use, shown by DF4JG. Mounted without touching the building fabric. (Uli, DF4JG, in German)

If the answer is no

Then there are four routes, and three of them are faster than the legal one.

Arbitration board. In Vienna and in other municipalities with their own arbitration board, this route precedes the district court. In Vienna it is MA 50, housing subsidies and the arbitration board for housing law matters, at Muthgasse 62 in 1190 Vienna. The proceedings are free, the facts are investigated, there is usually an oral hearing, and if no settlement is reached the board decides on the merits. Only then does it go to court. In municipalities without a board the route leads directly to the district court. In a condominium it runs through non-contentious proceedings at the district court.

Stay inside. Whatever does not leave the flat needs nobody's consent. Attic, window frame, indoor loop. The price is one to two S-units, documented with measurements in stealth antennas.

Set up temporarily. An antenna that goes back into the cupboard after the session is not an alteration of the rented object. A telescopic radiator on a tripod on the balcony, or the kit in a rucksack for SOTA and POTA, moves the question from the property manager into the open air.

https://www.youtube.com/watch?v=ztGXxLcOGrA

A QSO with the balcony loop, recorded. Useful when somebody claims nothing works with such an antenna anyway. (Dilettant45, in German)

Operate elsewhere. The club station has an antenna nobody argues about. And if you want it permanently, put the station where the antenna belongs and operate it over the network. What that looks like in practice is in the remote shack.

Lightning protection: the argument property managers raise first

As soon as an outdoor antenna is involved, the question of lightning protection and liability comes up. Being prepared for it looks professional, and the standards are clearer than one might think. The relevant documents are the OVE information sheet BL02 in its 2021 edition, which explicitly addresses amateur radio antennas, the lightning protection series OVE EN IEC 62305, under which antenna installations are to be assessed at protection class III as a minimum, and OVE EN 60728-11 for earthing and equipotential bonding of receiving and amateur radio antennas. For the electrical installation in the shack, OVE E 8101 has applied since 2019, replacing the frequently quoted ÖVE/ÖNORM E 8001. Cross-sections for supplementary protective equipotential bonding: at least 2.5 mm² mechanically protected, at least 4 mm² unprotected.

For a small balcony antenna with no connection to the building's lightning protection system this stays manageable. As soon as you connect to an existing system it belongs in the hands of a specialist firm, and saying exactly that in your letter takes the wind out of the discussion. The details are in our article on station earthing and lightning protection.

Insurance

Three policies matter, and none of them covers everything automatically.

Liability: if the antenna comes down in a storm and hits a car, you are liable. Private liability policies usually cover this, but check whether antenna installations are expressly included or excluded.
Household contents: damage to your own installation from storm, hail or lightning is often but not always covered, and outdoor antennas like to appear among the exclusions.
The owner's building insurance: if a leaking cable feed-through causes moisture damage, the recourse comes to you.

A short enquiry with your own insurer costs nothing and produces a sentence for the letter that carries more weight than any assurance.

Neighbours and interference

Legally separate, practically decisive: if the neighbour has interference, an approved antenna quickly becomes a contested one again. The competent authority for interference reports is the Fernmeldebüro, not the RTR, and in the majority of cases the problem lies with the immunity of the affected device rather than with the station. That does not change the fact that the first step is always your own installation: common mode choke, ferrites on every cable, clean matching, and less power when in doubt. The systematic route to the source is in our EMC guide.

An unsolicited handful of ferrite cores for the neighbour's equipment has resolved more antenna questions than any statute.

A look at Germany

Germany has no antenna right that overrides the landlord either. An earlier version of this article claimed the German amateur radio act granted the right to erect antenna installations. That is not the case; the AFuG regulates admission to the amateur radio service, not the relationship with the building owner.

What Germany does have is dense case law on the balancing test: the Federal Constitutional Court requires a concrete case-by-case balancing between the tenant's freedom of information under Article 5(1) of the Basic Law and the landlord's property under Article 14(1), and schematic solutions are ruled out. Where no damage to the fabric and no significant visual impairment are to be expected, the landlord may be obliged to consent in good faith under § 242 BGB. In substance that is the same balancing idea as in § 9 para 1 MRG, only with different doctrine.

The short way through

Check whether the flat falls under the full application area of the Tenancy Act, because that determines whether the two-month deadline applies at all
Choose an antenna variant that touches no common parts and needs no drilling
Call the building authority and clarify the building law classification, in Vienna also the protection zone question
Serve the notification in writing and provably, with dimensions, a sketch and undertakings on restoration and liability
Wait out the two months and document the deadline
Answer objections factually, offer an alternative location, pre-empt the lightning protection and insurance questions
If it gets hard: the arbitration board, and meanwhile keep operating indoors or portable

And the sentence that describes most cases in the end: the antenna nobody talks about is the antenna nobody refuses. The law is plan B, choosing the right antenna is plan A.

73 – your oeradio.at editorial team

Transparency Notice

This article was researched and written with the support of AI (Claude, Anthropic) and completely revised on 28 September 2026. Several errors in the first version were corrected: the antenna privilege in § 9 para 2 no 5 MRG applies to receiving antennas and not to amateur radio, the two-month deemed consent in § 9 para 1 was missing, § 8 MRG was wrongly described as protecting the building fabric, the difference between full and partial application of the Tenancy Act was missing, the majority requirements in condominium law were misstated, the lightning protection standards were out of date, the RTR was named instead of the Fernmeldebüro for interference reports, and the description of the German amateur radio act was wrong. Sources for the revision were § 9 and § 1 para 4 MRG, § 16 WEG 2002 as amended in 2022, Supreme Court decision 5 Ob 199/03f, § 62a para 1 no 24 of the Vienna building code, the procedural descriptions of the province of Upper Austria and the Lower Austrian building code 2014, OVE information sheet BL02 as well as OVE EN IEC 62305, OVE EN 60728-11 and OVE E 8101, City of Vienna information on the arbitration board, the micro-census housing survey by Statistics Austria, and for German law the line taken by the Federal Constitutional Court and the Federal Court of Justice on satellite dishes. The title image shows a housing estate in Vienna-Penzing (Photo: Haeferl, CC BY-SA 4.0), the other photographs are by P e z i (CC BY-SA 3.0) and Krzysztof Popławski (CC BY-SA 4.0), all via Wikimedia Commons and credited at each figure. The embedded videos are from German channels. This article is not legal advice; in an individual case the lease, the condominium agreement, the building code and, in a dispute, the arbitration board or the court decide. Corrections and additions, including experience reports from negotiations with property managers, to kontakt@oeradio.at.

Der Beitrag Antennas and Tenancy Law in Austria: Who Has to Consent, and How Do You Get It? erschien zuerst auf OERadio.

Amateur Radio Legislation in Austria: AFG, AFV and What You Need to Know

Michael | OE8YML — Sat, 26 Sep 2026 07:00:00 GMT

Amateur radio is a technical hobby with a law of its own. That is unusual and it is a privilege: radio amateurs may build, modify and operate their own transmitters, they get dedicated frequency allocations and they may work internationally. The price is a set of rules worth knowing, because it determines which bands you may use, at what power, under which call sign and with what record keeping.

This overview reflects the situation in September 2026 and has been thoroughly corrected compared with its first version. That was necessary, because more has changed in the past three years than in the twenty before: power levels were extended upwards in 2023, licences have been time-limited since 2018 and the old open-ended ones are now expiring on a staggered schedule, and the amateur radio fee ordinance was repealed outright in 2025 and replaced.

The legal basis, in the right order

Contrary to what is often written, the Telecommunications Act is not the only foundation. Austria has a dedicated amateur radio law, and that is the more important norm.

Amateurfunkgesetz 1998 (AFG). It establishes the amateur service as a service in its own right: definitions, the licence requirement, prerequisites, examinations, call signs, competent authority and penalties. Anyone who only reads the TKG misses the essentials.

Amateurfunkverordnung (AFV), BGBl. II No. 126/1999. The implementing ordinance to the AFG and the document you actually deal with day to day. It has been amended several times, most recently by BGBl. II No. 61/2023. It contains the licence classes, the power levels, the band plan in its annexes, call sign formation and the operating obligations including the log.

Telekommunikationsgesetz 2021 (TKG 2021), BGBl. I No. 190/2021. The general framework for everything radio. For radio amateurs the relevant parts are frequency management, market surveillance of radio equipment under EU Directive 2014/53/EU and the powers of the authority.

Frequenznutzungsverordnung (FNV). It assigns the frequency ranges in concrete terms. The amendment of 13 March 2023 is the reason Austria allows more transmit power today than it used to.

Telekommunikationsgebührenverordnung 2025 (TKGV 2025), BGBl. II No. 356/2024. In force since 14 July 2025. It replaced the old amateur radio fee ordinance, whose provisions were repealed in full. All amounts below come from this ordinance.

All amateur radio law is published in the Federal Law Gazette and is freely available through the RIS database. Advice found in a forum is worth checking there. (Image: official work, public domain, via Wikimedia Commons)

The competent authority

Responsibility rests with the Fernmeldebüro as the telecommunications authority. It is a subordinate agency of the Federal Ministry for Housing, Art, Culture, Media and Sport. That assignment has shifted with several government reshuffles, which is why older ministry names still circulate online.

The Fernmeldebüro issues licences, runs the examinations, coordinates frequencies, performs market surveillance on radio equipment and operates radio monitoring. Its seat is in Vienna at Radetzkystraße 2, with branch offices in Linz, Salzburg, Innsbruck, Bregenz, Graz and Klagenfurt. Lower Austria and Burgenland have no dedicated branch.

Licence classes

Austria has three licence classes. They differ in the scope of the examination, frequency access, permitted power and whether home-built equipment is allowed.

Class 1

The full class, with access to every band allocated to the amateur service, from long wave up into the microwave ranges. Home construction permitted, all power levels accessible. The examination meets the HAREC standard and therefore CEPT Recommendation T/R 61-01, which allows operation in CEPT countries without additional permission.

Class 4

The entry class with HF access. It covers several ranges, among them 160 m, 80 m, 15 m and 10 m plus 2 m and 70 cm. Operation only with commercially manufactured, unmodified equipment, and only at power level A. It corresponds to the CEPT Novice Recommendation T/R 61-02, so abroad the host country's novice conditions apply.

Class 3

The smallest class, limited to 144 to 146 MHz and 430 to 440 MHz, also with commercial equipment only and only at power level A. This class is purely national, there is no CEPT recognition for it. It is enough to get started via VHF repeaters, but not for HF.

Moving up to a higher class is possible through a supplementary examination, the whole exam does not have to be repeated. The minimum age for a licence is 14.

Power levels: the most important correction

The original version of this article got this wrong, in both directions. The correct scheme under § 9 AFV is:

Power level	Maximum power (PEP)	How you get it
A	100 watts	Default after passing the exam
B	200 watts	Application to the authority
C	400 watts	Application after one year of interference-free operation at level B from that site
D	1,000 watts	High power, since the FNV amendment of 13 March 2023, class 1 on selected HF bands

Two points, because they are regularly mixed up. First, level A is the default power, not the ceiling for the experienced. Second, the Austrian ceiling is 1,000 watts PEP, not 1,500 watts. High power at level D is available on 80 m, 40 m, 20 m, 17 m, 15 m, 12 m and 10 m, subject to at least one year of interference-free operation at level B from the site in question. Classes 3 and 4 are limited to level A by § 8 AFV, that is 100 watts.

Some bands carry their own lower limits regardless of level, for instance the long-wave segment at 135.7 to 137.8 kHz. What counts is always the band plan in the annexes to the AFV together with the FNV. And whatever the ceiling, the principle stands: use the minimum power necessary for the contact.

Licences now run for ten years

This is the change with the greatest practical consequences. Amateur radio licences are no longer issued indefinitely but for ten years. After that a new application is required.

For the many old open-ended licences there is a phase-out plan based on the year of issue:

Issue years ending in 8 or 9: expired on 31 December 2025
Ending in 0 or 1: expiry on 31 December 2026
Cohorts 1980 to 1989: expiry in 2026
Cohorts 1990 to 1994: expiry in 2027
From 1995 onwards: expiry in 2028, at the end of the month in which the licence was originally issued

The Fernmeldebüro notifies those affected in writing around two months in advance and encloses an application form. The formal route is to surrender the old open-ended licence and file a new application at the same time, so that operation continues without a gap. Miss the deadline and you no longer hold a valid licence and may not transmit. We have broken down the detail in a separate piece on the expiry of open-ended licences.

What it costs: TKGV 2025

The amateur radio fee ordinance is history, its provisions have been repealed. Since 14 July 2025 the TKGV 2025 applies. The positions relevant to radio amateurs under § 15:

Amateur radio licence: 200 euros once, covering the ten-year term
Club station: 800 euros for ten years
Change to a different licence class within the ten years: 50 euros
Licence on the basis of a foreign authorisation: 50 euros
Examination fee per category, including supplementary exams: 50 euros

On top of that come two charges under the Fees Act 1957: 21 euros for the application and 21 euros for the certificate, the latter only if you pass. The examination therefore costs 92 euros in total, of which 71 euros fall due before the appointment. From 1 January 2027 the amounts are index-linked and the licence rises to 206.40 euros per BGBl. II No. 267/2026.

Spread over ten years that is roughly 20 euros a year for the licence. Internationally that is still cheap, but the frequently quoted 21 euros for the exam is out of date.

The examination

Three subjects are examined: legal provisions, operating practice and skills, and technical fundamentals. Each subject brings three questions, and the examiners work from the published question catalogue. The examination categories match licence classes 1, 3 and 4.

A Morse test is voluntary and only available in addition to category 1. It requires sending and receiving plain text at at least twelve words per minute for three minutes each. It has long ceased to be a prerequisite for normal operation, but it still makes sense for some awards and for its own sake.

Exams are usually held in Vienna at Radetzkystraße 2, with sittings in Graz, Linz and Innsbruck as well, and in Klagenfurt and Hard when needed. The invitation with the details arrives about two weeks beforehand. How preparation works and which courses exist is covered in our guide to the Austrian amateur radio exam.

https://www.youtube.com/watch?v=VMAfg-6KkTk

How an amateur radio examination runs, filmed in Germany. The subjects and the procedure compare well with Austria, the fees and classes differ. (Arthur Konze, in German)

Call signs

Austrian call signs consist of the country identifier OE, a digit for the province and a suffix of one to three letters. The digits: OE1 Vienna, OE2 Salzburg, OE3 Lower Austria, OE4 Burgenland, OE5 Upper Austria, OE6 Styria, OE7 Tyrol, OE8 Carinthia, OE9 Vorarlberg.

Plus the additions set out in § 22 AFV:

Operation in another province: slash plus the digit of the province you are operating from
/M for mobile, /P for portable operation
/MM for maritime mobile, /AM for aeronautical mobile
Club stations: the letter X is inserted into the call sign
Visitors holding a CEPT licence in Austria: prefix your own call sign with OE/

The call sign must be unmistakably identifiable, and in text or image transmissions separated by at least one blank field. During longer transmissions it must be sent at least every ten minutes. Allocation is made by the authority, preferences may be expressed, but there is no legal entitlement to a particular call sign.

https://www.youtube.com/watch?v=eC7SG5RPt6U

How a call sign reveals the class and country behind it. The examples are German, the systematics are international. (Joerg Klamke, DA6PP, in German)

Operating obligations

The log: yes, it is mandatory

The first version of this article was wrong here too. § 24 AFV requires a log with consecutively numbered pages, signed by the licence holder or the responsible person. Each contact needs date, start and end time, the other station's call sign or CQ for general calls, frequency, mode and location.

There are concessions. In mobile operation above 30 MHz, date, time span, frequency range and area suffice. Operators with a physical disability may limit themselves to date, time span and frequency band, and an audio recording counts as a log. In practice any electronic logbook satisfies the requirements as long as the mandatory fields are there and it can be printed or exported.

Intelligibility instead of encryption

The AFV frames the encryption ban from the other side: under § 20 para. 5 the use of devices that restrict the intelligibility of the message is not permitted. Standardised procedures, meaning the usual digital modes with openly documented coding, are not affected. For non-standardised procedures § 20 para. 3 requires that transmissions remain reproducible for three weeks.

No broadcasting

Amateur radio is communication between radio amateurs, not programming for the general public. Music, advertising and transmissions to an undefined audience are not permitted. CQ calls and the bulletins of the national societies are expressly fine.

Reception

§ 19 AFV limits what may be received with the amateur station, namely transmissions in the ranges allocated to the amateur service, broadcasting, public announcements and emergency and disaster traffic. This is not a ban on running an SDR, but it does constrain the amateur station itself.

Emergency traffic

Emergency traffic takes priority and distress calls must be relayed. What the international side says, and what the updated recommendation ITU-R M.1042-4 means for Austria, we covered separately.

Training operation

§ 23 AFV allows a class 1 club station to be used by holders of examination categories 3 or 4 where this serves training purposes and happens under the supervision of a class 1 holder. That is the legally clean way to put newcomers on the microphone.

Technical duties and EMC

The AFV also covers technical matters. Unwanted emissions must be limited under § 17, and tuning the transmitter must be done into a dummy load able to absorb the licensed power under § 14. Repeaters and beacons have their own rules, among them that a repeater must stop transmitting within ten seconds after the end of reception, or within three minutes for television.

For interference the Fernmeldebüro is the place to go. It accepts reports, can measure on site and order measures. The proven sequence remains: check your own station first, then talk to the neighbour, and only then involve the authority. How to track down interference sources systematically is in our EMC guide. Anyone planning to put up an antenna should also know the civil law side, which we wrote up in antennas and tenancy law.

Operating abroad

Class 1 equals HAREC and therefore T/R 61-01, so operation in CEPT countries is possible without additional permission, using the host country prefix before your own call sign. Class 4 falls under the novice recommendation T/R 61-02 and applies in those countries that have implemented it, subject to their national novice conditions. Class 3 is national and does not authorise operation abroad.

Outside the CEPT area an individual authorisation is usually required. If you are planning a SOTA or POTA trip, settle the question before you are on the summit.

Comparison with Germany

The comparison is worth making because many operators are active in both countries. It shifted in 2024, when Germany introduced a new entry class.

Authority: Fernmeldebüro in Austria, Bundesnetzagentur in Germany
Classes: Austria has 1, 3 and 4. Germany has had three classes N, E and A since the amendment of 24 June 2024, with N limited to 10 m, 2 m and 70 cm at a maximum of 10 watts
Maximum power: Austria 1,000 watts PEP at level D on selected HF bands, Germany 750 watts PEP in class A. The Austrian advantage is real, but smaller than often claimed
Exam costs: Austria 92 euros including application and certificate, Germany in a similar range depending on class
Licence term: Austria ten years with a fee covering the period, Germany recurring contributions under its frequency usage contribution ordinance
Site certification: more formalised in Germany under the BEMFV than in Austria
Society: ÖVSV in Austria, DARC in Germany, both IARU members with a QSL bureau

https://www.youtube.com/watch?v=S43cWGlTZDY

The German classes N, E and A at a glance, useful for anyone operating near the border or moving across it. (Funkwelle, in German)

How this differs from licence-free services

Amateur radio is not citizens' band radio. CB, PMR446 and Freenet need no exam and no licence, but frequencies, power and equipment choice are tightly limited and home construction is not part of the deal. The examination is precisely why radio amateurs may do so much more. If you are weighing up which route suits you, amateur radio as a hobby takes the beginner's view.

Penalties

Breaches are administrative offences. Fines, revocation of the licence and seizure of equipment are all possible. Transmitting without a valid licence is an offence regardless of whether anyone is being interfered with. That is exactly why the time limit is not a formality: an expired licence is no licence.

In practice the authority starts with education. It gets serious with repetition and with deliberate interference.

The ten points that really matter

Hold a valid licence, and keep an eye on the expiry date. Ten years pass faster than you think
Send your call sign, at least every ten minutes during longer transmissions
Use only the bands of your own class
Stay within your power level, the default is 100 watts and more only with a decision in hand
Keep a log with the mandatory fields from § 24
Transmit nothing that restricts intelligibility
No broadcasting and no music
Emergency traffic takes priority
Take responsibility for EMC and limit unwanted emissions
Clarify the CEPT status of your destination before you travel

Austrian amateur radio law remains liberal: high power limits, low fees, home construction cleanly regulated, straightforward operation across Europe. What is new is that you now need a date in your calendar. Renew the licence in time and keep the log properly, and you will hardly ever deal with the authority at all.

73 – your oeradio.at editorial team

Transparency Notice

This article was researched and written with the support of AI (Claude, Anthropic) and completely revised on 26 September 2026. That revision corrected several errors in the first version, in particular the power levels, the maximum transmit power, the citation of the Amateurfunkverordnung, the logging obligation and the fees. Sources for the revision were the consolidated texts of the Amateurfunkgesetz 1998 and the Amateurfunkverordnung in the Austrian RIS database, the Telekommunikationsgebührenverordnung 2025 including its indexation from 2027, the Fernmeldebüro information pages on examinations, fees and the expiry of open-ended licences, ÖVSV announcements, and the German rules under the 2024 Amateurfunkverordnung for the country comparison. The title image shows the office building at Radetzkystraße 2 in Vienna, seat of the Fernmeldebüro (Photo: Yair Haklai, CC BY-SA 4.0, via Wikimedia Commons); the other illustration is an official work in the public domain. The embedded videos are from Germany and labelled accordingly; for Austrian law the provisions stated here apply. Editorial responsibility and review lie with the oeradio.at editorial team. We accept no liability for accuracy or completeness; in an individual case the Fernmeldebüro decides. Corrections and additions to kontakt@oeradio.at.

Der Beitrag Amateur Radio Legislation in Austria: AFG, AFV and What You Need to Know erschien zuerst auf OERadio.

Receiving Paragliders and Gliders: An OGN Station and OpenWebRX+ on One Raspberry Pi

Michael | OE8YML — Fri, 25 Sep 2026 07:00:00 GMT

Stand at Lake Ossiach in summer and look up towards the Gerlitzen, and from late morning on you will see the first canopies circling in the thermals. What you do not see: most of them are transmitting. Every few seconds a short data packet goes out on 868 MHz carrying position, altitude, climb rate and an identifier. Glider pilots do the same thing with FLARM, motor gliders and microlights increasingly with ADS-L, and a handful of tinkerers with home-built ESP32 trackers.

All of this is picked up by ground stations that radio amateurs, clubs and airfields run voluntarily. The network behind them is called the Open Glider Network, OGN for short, and it consists of nothing more than many small Linux machines with an SDR dongle and an antenna. If you already have a mast, you can build such a station in an afternoon. And because a Raspberry Pi today does more than saturate a single task, you can run your own WebSDR on the same box. That is what this article is about: what is actually flying up there, why joining in is worth it, and how to get OGN and OpenWebRX+ to live side by side on one device.

What is actually transmitting up there

The band in question is the European SRD band at 868 MHz. It is licence free, power limited, and next to radio sensors, smart meters and LoRa mesh networks it also hosts the small electronics of sport aviation. Four systems matter.

FLARM is the classic in gliding. Originally built as a collision warning system between sailplanes, it broadcasts position and flight vector to its surroundings so the instruments in the cockpit can warn. These transmissions are what OGN picked up, and what made the network interesting in the first place.

FANET is the equivalent for paragliding and hang gliding. It uses LoRa in the same band, comes from vario manufacturer Skytraxx and the protocol is openly documented. You find it in devices from Skytraxx, Syride, Naviter and in the beacons around the burnair platform. FANET does two things that set it apart: pilots see each other directly, without any infrastructure, and it also carries weather station data and thermal reports.

ADS-L is the new, official route. EASA published the technical specification for the SRD 860 band in early 2023. It uses 868.2 and 868.4 MHz plus 869.525 MHz and was deliberately designed so that existing hardware can join in. For radio amateurs the interesting part is that for the first time there is an open, regulator-endorsed standard for electronic conspicuity in light aviation.

Home-built trackers finally run on ESP32 boards, typically a LilyGO T-Beam with an SX1276 radio chip and GPS, for under 40 euros. The firmware is open source and, depending on the project, transmits OGN, FANET, ADS-L and PilotAware. Important for anyone rebuilding: the frequently linked esp32-ogn-tracker repository has been unmaintained for years, the current one is pjalocha/ogn-tracker, with SoftRF as an alternative. And the band variant has to be right, 868 MHz in Europe.

https://www.youtube.com/watch?v=0RITXaCFxGM

A compact introduction: what the Open Glider Network is and what a receiving station does (Caz Yokoyama)

Why you should do it

The honest answer first: because there are gaps and you can close them. The OGN network is dense over the Alps but not seamless, and the gaps are typically where mountains block the path and nobody runs a receiver. A radio amateur with a mast on a slope often covers exactly the valley nobody else hears.

Four concrete reasons follow from that.

Search and rescue. This is the one that counts. When an aircraft or a canopy goes missing, the last received positions are the most valuable thing the rescue services can get. OGN keeps live data, archived traces and the FlightBook, which lets you narrow down even unregistered devices by departure site and time. The project itself points out that this data can be ambiguous and needs careful checking before it is passed to the rescue coordinator. Still, the denser the receiver network, the shorter the final gap in the track. That is what the network was originally built for.

Benefit for local aviation. Clubs see who is airborne and who has landed. Instructors can debrief training flights. Paraglider pilots receive wind reports from mountain stations on their vario over FANET, which on a gusty afternoon is worth more than any forecast.

Technical insight. An OGN station is a permanently running measurement point for your own antenna system. The coverage map that emerges after a few weeks shows mercilessly where the site is shadowed, what a preamplifier actually contributes and how badly the neighbouring transmitter interferes. Anyone already receiving ADS-B or chasing radiosondes knows the effect.

And the low barrier to entry. A receiving station needs no licence and no exam. That makes it an ideal project for newcomers, for the youth section of a club and for anyone who wants to listen before they transmit.

https://www.youtube.com/watch?v=AZ6dVCxGaNc

A detailed talk on FLARM and OGN, including building and operating a ground station (Colin Sindle)

The hardware

The shopping list is short and the most expensive item is the antenna, not the receiver.

Computer: Raspberry Pi 3 or 4. A Pi 4 is the sensible choice because FANET and PilotAware cost extra processing power. A Pi Zero or Pi 1 only manages simple reception with compromises. Any small Linux box or thin client works too.
SDR dongle: The RTL-SDR Blog V3 with TCXO, SMA connector and switchable bias tee is the project's recommendation. Note, and this surprises many people: the newer V4 is currently explicitly not recommended for OGN because it performs worse in this application. If a V4 is all you have in the drawer, use it for the WebSDR side.
Antenna: Vertical omnidirectional for 868 MHz, collinear with 5 to 9 dBi. The widely used 165 cm fibreglass antenna in the 9 dBi class serves as the reference. Vertical polarisation and a clear view are what matter.
Optional but effective: A filtered masthead preamplifier from Uputronics adds roughly 3 to 5 dB, mounted right at the antenna and fed over bias tee. If you live near strong transmitters you rather need a cavity filter for 863 to 870 MHz, otherwise intermodulation eats your range.
Cable: Short and good. Loss ahead of the first amplifier comes straight off your sensitivity. For the mechanical side see our article on towers and masts.
Power and network: Stable 5 V, ideally a proper power supply and a powered USB hub once two dongles are attached. Wired Ethernet wherever possible.

An RTL-SDR dongle for around 30 euros is the heart of the station. For OGN the project recommends the V3 variant with TCXO. (Photo: Dsimic, CC BY-SA 4.0, via Wikimedia Commons)

Guide, part 1: the OGN station

The basis is a freshly installed Raspberry Pi OS Lite with SSH enabled and the system up to date. The procedure follows the official guide in the OGN wiki, and the short version looks like this.

Install packages. The software needs a few libraries:

sudo apt update && sudo apt full-upgrade -y
sudo apt install -y libconfig9 libjpeg-dev libfftw3-dev procserv telnet lynx ntpsec

On newer systems libjpeg8 is missing from the package sources. The wiki describes two ways around this, either building libjpeg from source or using prepared ARM64 binaries. This is the one step where installation on current images regularly stalls, and the reason many stations deliberately still run an older Raspberry Pi OS.

Fetch the software and create the pipe. The matching rtlsdr-ogn package comes from the project's download area, the GPU variant for the Pi. Then create the named pipe through which the RF part talks to the decoder:

cd ~/rtlsdr-ogn
mkfifo ogn-rf.fifo

Measure the frequency error. Dongles without a TCXO run a few ppm off, which costs sensitivity. The bundled tool measures the error against GSM channels:

./gsm_scan --ppm 50 --gain 20

With a V3 and its TCXO you can skip this and leave FreqCorr at 0. During operation the software recalibrates against GSM anyway.

Write the configuration. The file, here mystation.conf, is compact. Position and altitude must be entered accurately, the software also derives the regional frequency plan from them:

RF:
{
  FreqCorr    = 0;             # ppm, 0 for TCXO dongles
  BiasTee     = 1;             # power for the masthead preamp
  DeviceSerial = "OGN01";      # address the dongle unambiguously
  PipeName    = "ogn-rf.fifo";
} ;

Position:
{
  Latitude    =  46.6883;      # decimal degrees, north and east positive
  Longitude   =  13.9186;
  Altitude    =   900;         # metres above sea level
} ;

APRS:
{
  Call        = "OE8XYZ";      # max. 9 characters, publicly visible
} ;

HTTP:
{
  Port        = 8080;          # status page of the station
} ;

The name under Call is the public identity of the station. Airfields use their ICAO code, private stations a meaningful place name or their own call sign. Avoid special characters, nine characters maximum.

Run it as a service. The project's start scripts use procserv, and the configuration file is registered in /etc/rtlsdr-ogn.conf:

sudo service rtlsdr-ogn start
lynx http://localhost:8080

From here the station is running. The status page on port 8080 shows noise levels, received packets and the list of heard devices, and a few minutes later the station appears on the map at live.glidernet.org. If you want to see what arrives at your own site: the receiver names visible there are exactly these stations, in Carinthia for instance LOKF at Lake Ossiach.

A Raspberry Pi 4 carries the OGN decoder and a WebSDR at the same time, as long as each service has its own SDR dongle. (Photo: Laserlicht, CC BY-SA 4.0, via Wikimedia Commons)

Guide, part 2: OpenWebRX+ alongside

OpenWebRX+ is Marat Fayzullin's fork, which added a whole range of decoders to the original OpenWebRX: SSTV, FAX, AIS, POCSAG, FLEX, RDS, CW, RTTY, plus ADS-B, ACARS, VDL2 and HFDL. It installs from the project repository, here for Debian Bookworm, which the current Pi images are based on:

curl -s https://luarvique.github.io/ppa/openwebrx-plus.gpg \
  | sudo gpg --yes --dearmor -o /etc/apt/trusted.gpg.d/openwebrx-plus.gpg
sudo tee /etc/apt/sources.list.d/openwebrx-plus.list <<<"deb [signed-by=/etc/apt/trusted.gpg.d/openwebrx-plus.gpg] https://luarvique.github.io/ppa/bookworm ./"
sudo apt update
sudo apt install openwebrx

Two pitfalls: the original OpenWebRX repository must not additionally be configured on Bookworm, it carries Bullseye packages. And for the digital voice modes you need to run sudo install-softmbe.sh once. If you prefer to start from scratch, take one of the project's ready-made SD card images, but be aware that the 32 bit image does not serve the Pi 5 and the 64 bit image excludes Pi 1, Pi 2 and Zero 1.

After that, create an admin user, open the web interface on port 8073 and add the second dongle in the device section, addressed by its serial number rather than its index. If you want the receiver reachable from outside, our article on Cloudflare Tunnels describes the route without an open port.

https://www.youtube.com/watch?v=opolawcWJvQ

Setting up OpenWebRX+ on a Raspberry Pi, step by step (Kevin O'Reilly)

The combination: why two dongles are mandatory

The obvious idea of serving both services from one dongle does not work, for three reasons.

First, an RTL-SDR dongle is always claimed by exactly one process. There is no sharing at driver level. Second, the OGN software does the one thing that rules out shared operation for good: it periodically retunes the dongle into the GSM band to track the oscillator error. A waterfall that jumps away every few minutes is not a waterfall. Third, and this is often overlooked, OpenWebRX+ has no OGN decoder. Its built-in ISM branch is based on rtl_433 and reads radio sensors, it cannot do LoRa and therefore cannot do FANET. On 868 MHz you see the bursts in the waterfall, but nothing decodable comes out of it.

The solution is unspectacular: two dongles. So that both services grab the right device after a reboot, give them unambiguous serial numbers:

rtl_eeprom -d 0 -s OGN01
rtl_eeprom -d 1 -s WEBRX1

Then set DeviceSerial = "OGN01" in the OGN configuration and select the second dongle in OpenWebRX+ via WEBRX1. The rest is operational practice, and the three points are well known: the Pi's USB ports do not reliably supply enough current for two dongles, so a powered hub belongs in the setup. Under continuous load it gets warm, so use heat sinks or better a quiet fan. And the two dongles should not sit directly next to each other, a short USB extension decouples them noticeably.

Incidentally, the same pattern scales. The OGN wiki explicitly describes running multiple receivers on a quad-core Pi, each with its own pipe, its own configuration and its own HTTP port. So if you want OGN, ADS-B and a WebSDR on one box you can have it, but you have to get serious about power supply and cooling. What else runs on a Pi in the shack is collected in Raspberry Pi in the Shack.

Site, range, expectations

On 868 MHz line of sight rules without mercy. The antenna belongs as high and as free as possible, and every metre of height pays off more than any decibel of gain. At a quiet site 50 to 100 kilometres is achievable, more with line of sight across a valley. Near mobile or broadcast transmitters, on the other hand, the range can collapse to a few kilometres because the receiver runs into intermodulation. Only filtering helps against that, not more gain.

For the Alps this means: good sites are slopes and mountain stations with a view into the valley, not the valley floor itself. If you already run a mast for APRS or a repeater, half the installation is already standing. The combination of an exposed site and a FANET-capable station is worth considerably more to the local paragliding scene than yet another station in the already well covered lowlands.

Privacy and legal situation

The most important point first, because it was discussed emotionally in the flying community and is cleanly solved today: tracking can be switched off. Anyone who does not want to be visible sets the corresponding flag in the OGN device database DDB or enables the no-tracking option in their FLARM unit from firmware 6.x onwards. The position is then neither shown nor recorded. As a station operator you should be able to explain that, it takes the heat out of the discussion immediately.

As for reception itself: a receiving station does not transmit, so it needs no authorisation. The transmissions in the SRD band are unencrypted position beacons whose entire purpose is to be heard by others. When redistributing data, however, keep a sense of proportion. Secrecy of telecommunications knows no exception for interesting data, and OGN has its own usage rules for passing data on. Anyone feeding the official network operates within those rules. Anyone publishing their own analyses should know them. Our article on amateur radio legislation in Austria gives an overview of the legal framework.

And one clarification that belongs in every station description: OGN is not a safety system. Collision warning happens in the cockpit, between the devices, in real time. The ground network only sees what happened to be within range of a station, with delay and with gaps. It is a tool for debriefing, for live tracking and, in an emergency, for the search, not for the second in which it matters.

What it costs

Raspberry Pi 4 with power supply, case and card: around 90 to 120 euros
RTL-SDR Blog V3: about 35 euros, and the same again for the second dongle for the WebSDR
868 MHz collinear antenna: 40 to 120 euros depending on the model
Cable, connectors, mast hardware: 30 to 80 euros
Optional masthead preamp or filter: 40 to 90 euros

All in, a solid dual station lands at roughly 250 to 400 euros, assuming the mast is already there. For comparison: a ready-made vario with FANET costs more. If you just want to sniff around, start with a single RTL-SDR dongle and an improvised antenna and see what arrives at all.

Conclusion

An OGN station is one of the few projects where tinkering fun and genuine use meet this directly. The effort is an afternoon plus antenna work, the running cost is a few watts of electricity, and in return your receiver sits in a network that in an emergency delivers the last known position of a missing pilot.

That a WebSDR can run on the same machine is the bonus. The rule for it is simple: one service, one dongle, unambiguous serial numbers, proper power supply. Follow that and you end up with a box that serves local aviation and opens your own reception to everyone on the web at the same time. For a hobby that lives on listening, that is not a bad trade.

73 – your oeradio.at editorial team

Transparency Notice

This article was researched and written with the support of AI (Claude, Anthropic). Sources included the Open Glider Network wiki with its pages on hardware, Raspberry Pi installation, the configuration file, multiple receivers, SAR and the opt-out rules, the package instructions of Marat Fayzullin's OpenWebRX+ project, EASA's ADS-L specification for the SRD 860 band, the project pages on FANET and the ESP32 trackers, as well as a live query of the OGN map for the alpine region. The title image shows a paraglider above the Gerlitzen in Carinthia (Photo: Superbass, CC BY-SA 4.0, via Wikimedia Commons), the other photos also come from Wikimedia Commons and are credited at each figure. Editorial responsibility and review lie with the oeradio.at editorial team. We accept no liability for accuracy or completeness; legal questions are settled case by case by the telecommunications authority. Corrections and additions, very welcome from operators of their own OGN stations, to kontakt@oeradio.at.

Der Beitrag Receiving Paragliders and Gliders: An OGN Station and OpenWebRX+ on One Raspberry Pi erschien zuerst auf OERadio.

Remote Shack: Control Your Amateur Radio Station from Anywhere

Michael | OE8YML — Mon, 21 Sep 2026 07:00:00 GMT

An antenna belongs where it works well. You belong where you live. Those two places are rarely the same, and remote operation grew out of exactly that gap.

The principle is simple: transceiver, amplifier, tuner and antenna live at a fixed site, and you reach them over the Internet. Three things travel down that link, and it pays to think of them separately from the start. First, control commands, meaning CAT: frequency, mode, PTT, filters. Second, audio in both directions. Third, optionally, spectrum and waterfall data. Most remote-operation problems are really a problem with exactly one of those three streams, and knowing which one is misbehaving is half the troubleshooting done.

Why bother

The most common reason is space. If you live on the third floor of a rented flat, a three-element Yagi is not going on the balcony, and depending on the house rules neither is a wire. What is legally possible and what is not, we unpacked in Antennas and tenancy law in Austria. A site in the countryside, at your brother's place, at a cabin or at a club colleague's house solves the problem without you having to move house.

The second reason is the noise floor. In built-up areas, 40 metres in the evening will happily sit at S7, and that is rarely down to one single source. It is the sum of switching supplies, LED drivers, PV inverters and the neighbour's charger. How to hunt those down is covered in our EMC guide. The catch is that some of it simply cannot be switched off, and at that point a quiet site ten kilometres away is worth more than any preamp.

Two more reasons get discussed less often. One is time: if you work away from home during the week, remote access means being on the air on a Tuesday evening rather than only at weekends. The other is access. For operators who can no longer manage the loft or the cellar easily, remote operation is not a convenience feature. It is often the difference between still being active and no longer being active.

Start for free: wfview

If you own an Icom station, getting started costs nothing. wfview is free open-source software for Windows, macOS and Linux, and it has become the obvious answer to the question of where to begin.

For radios with a built-in network port, meaning the IC-7610, IC-9700, IC-705, IC-905, IC-R8600 and, on the Kenwood side, the TS-890S, wfview connects straight to the radio's IP address. For everything else, above all the widespread IC-7300, there is server mode: a computer at the site hangs off the transceiver over USB and becomes the network device itself. That can be an old laptop or a Raspberry Pi.

Three points matter here, and they are stated plainly in the manual. wfview uses three UDP ports, 50001 for control, 50002 for receive audio and 50003 for transmit audio, and those port numbers must not be remapped, because they are part of the protocol itself. For the codec, Opus at one channel is the right choice, using four to ten times less bandwidth than PCM depending on the comparison. And the user management is deliberately basic: the manual says outright that passwords are not well encrypted and that you should not use a sensitive password there. Which is exactly why wfview belongs behind a VPN rather than on the open Internet.

Typical audio latency, according to the project, is under 75 ms on a LAN and under 200 ms over the Internet. For SSB that is plenty. For CW it gets marginal depending on your link. More on that below.

https://www.youtube.com/watch?v=BZxW9AESIBk

wfview in overview: free remote control for many Icom radios (Kevin Loughin, EN)

Worth a footnote because of where it points: wfview now has a headless fork called wfweb that makes the station operable from a browser, audio and digital modes included. If you would rather not install client software at all, that is an interesting direction.

The manufacturer solutions

FlexRadio SmartLink

The FLEX-6000 series is popular for remote work because the radio is fundamentally a network device with an antenna socket. SmartSDR looks the same on the LAN as it does over the Internet, audio, waterfall and control share one connection, and the latency is remarkably low.

One widespread claim about it is wrong, however, and an earlier version of this article repeated it: SmartLink does not generally avoid port forwarding. FlexRadio's own helpdesk states that the router at the station site must be able to accept an incoming connection from the Internet, typically through port forwarding. SmartLink tries to set this up automatically via UPnP, which often works and often does not. When it does not, you end up either forwarding ports manually or reaching for one of the overlay networks described below.

Icom RS-BA1 and the IC-7760

Icom's RS-BA1 version 2 is the in-house solution, split into a server part at the site and a client. It does more than wfview when it comes to integration with the Icom world, and it costs money for the privilege. If you own an IC-7610 anyway, try both and decide.

More interesting is what Icom did with the IC-7760. The radio comes in two parts, a control head and an RF deck, and the two talk to each other over LAN, either within the house or across the Internet. A three-metre control cable ships with it; for anything longer you use an ordinary network cable. Up to five control heads can be registered with the RF deck, with only one taking control at a time. Icom states that the radio adjusts its buffer under network delay and jitter so that CW keying stays precise. That is the genuinely interesting part of this architecture: the RF deck can finally sit where it belongs, close to the feed point, rather than where there happens to be desk space.

Kenwood: KNS, ARCP-890 and ARCP-990

Kenwood calls its system the Network Command System, KNS for short. On the TS-890S, which has a network port built in, ARCP-890 controls the radio directly over LAN or Internet, with audio handled by the VoIP function built into both the radio and ARCP-890. In the classic arrangement you additionally need ARHP-890 as the host program and ARVP-10 for voice. For the TS-990S there is the corresponding ARCP-990.

What is no longer available

The RemoteRig RRC-1258MkII boxes from Microbit were the standard answer to the remote question for years, because they needed no PC and simply extended a radio's detachable control head across the Internet. They are no longer sold. They still turn up on the used market, and if you have a pair, keep them. As a new build, that route is closed.

Rolling your own with a Raspberry Pi and Hamlib

Fifteen watts of continuous load, and half the remote shack runs on it. Photo: RAIL P (RAIL.PHOTOGRAPHY), CC0, via Wikimedia Commons.

If you do not own an Icom, or you simply like building things yourself, free software gets you just as far. The skeleton has three parts.

Hamlib with rigctld handles control. The daemon attaches to the transceiver's serial or USB port and offers the CAT commands over TCP/IP, port 4532 by default. Programs such as WSJT-X, FLRig, CQRLOG or Gpredict connect to it across the network as though the radio were sitting next to them. Hamlib covers virtually any transceiver that has a CAT interface at all.

For audio, Mumble has proven itself, because it is designed for low latency and sounds good on little bandwidth. At the site the transceiver's AF is digitised through a USB audio interface; at the operator end it goes the other way into a microphone. Discord or TeamSpeak work too, but they are noticeably more sluggish, because they were built for conversations rather than for PTT.

For hardware, a Raspberry Pi from model 4 onwards is enough. Power draw stays in the five to fifteen watt range, which makes continuous operation realistic even on a solar supply. What that means for sizing a battery is in Akkublick. We collected further uses for a Pi in the shack in a separate article.

The advantage of this build is that every piece can be swapped individually. The drawback is that you are now looking after three services instead of one, and that debugging them across an Internet link teaches you how little fun that is.

https://www.youtube.com/watch?v=UlqanVnHkA0

Remote control at no extra cost, explained step by step (DX Commander, EN)

The networking problem nobody mentions: CGNAT

This is where most remote projects die, before they have properly started. Many Internet connections no longer get their own public IPv4 address; they share one with hundreds of other customers. That is called Carrier-Grade NAT, and it particularly affects mobile and LTE connections, which is exactly what you often have available at a cabin or a garden plot.

The consequence: port forwarding does not work. There is nothing to forward, because your router has no address that anyone outside could reach. You can write firewall rules for hours and nothing will change.

Finding out whether you are affected takes two minutes. Check which WAN IP address your router holds and compare it with the address a site like ifconfig.me reports. If the two differ, or if the WAN address starts somewhere between 100.64 and 100.127, you are behind CGNAT.

The answer is an overlay network. These services build the connection outward from both ends, which any firewall happily allows, and then connect your devices directly to one another. From the software's point of view it looks like a local network.

Tailscale is the quickest to set up, builds on WireGuard and is free for personal use. We walked through a concrete example using the IC-705: IC-705 remote operation with Tailscale.
ZeroTier does the same job with a slightly different philosophy and is equally common in the remote community, not least as the way out for FlexRadio setups stuck behind CGNAT.
Plain WireGuard is the option without a third-party service in the middle. It does require that at least one of the two ends is reachable from outside, for example a small hosted server that both ends meet at.

One side effect worth taking: if everything runs through an encrypted tunnel anyway, half the security chapter takes care of itself.

Latency: what actually counts

The number everyone looks at is ping. Consistency matters more.

For SSB, anything under roughly 200 ms goes unnoticed. You feel the delay when switching, but it does not get in the way. CW is stricter: under 100 ms you can work properly, under 50 ms you barely notice a difference from local operation, and above that, listening to your own sending starts to become unpleasant. It is no accident that Icom explicitly advertises buffer adjustment for CW keying on the IC-7760. For FT8, FT4 and other digital modes, latency is practically irrelevant as long as the clocks are right, because decoding happens in fixed time windows regardless.

The real enemy is jitter, the variation in transit time. A link with a steady 150 ms is more pleasant than one bouncing between 40 and 180 ms, because every buffer has to be sized for the worst case. Packet loss above one percent shows up as dropouts in the audio and as stuck commands in the control path. If your router does QoS, the remote traffic deserves priority, especially if someone at home is streaming at the same time.

Bandwidth is usually wildly overestimated. Pure audio in both directions gets by on 128 kbit/s. With control, a camera and a modest waterfall you are at two to five Mbit/s. Only if you want the full waterfall of an SDR station at high resolution does it go into double digits. And that is upload at the station end, not download, because that is where the data comes from.

What has to be at the far end

A contest station that grew over time. Every box on that desk you might need from a distance has to be remotely controllable or switchable. Photo: Ptolusque, CC BY-SA 4.0, via Wikimedia Commons.

The golden rule: anything you would have to touch when something goes wrong, you must also be able to touch remotely.

Top of the list is the network-controlled power strip. It is not a luxury, it is the insurance policy for the whole project. When the transceiver locks up or the router drifts into a strange state, a remote power cycle is the difference between a two-minute outage and a car journey. One thing matters here: the computer that controls the power strip must not itself hang off the switched side. That sounds obvious and is still regularly wired up wrong.

Next is a UPS, which helps less against long outages than against the brief dips after which a computer fails to come back up cleanly. Models with a network port can be monitored and can shut things down in an orderly fashion.

An IP camera with night vision sounds like a toy and is not. Being able to look at an SWR meter while sitting three hundred kilometres away answers questions no software will answer for you. Whether the rotator is actually turning, for instance.

On antennas, the fewer moving parts, the better you sleep. Remote switches are standard, both off the shelf and home-built with a relay board and a microcontroller. An automatic tuner at the site saves you retuning from a distance. Motor-adjustable antennas cover many bands on one cable, but they also bring a motor, which at minus fifteen degrees in January does exactly what motors do then.

And finally the watchdog. Something has to put the station into a safe state if the link drops mid-transmission. Without that mechanism, a crashed client can leave PTT asserted, and then you are transmitting a carrier until somebody drives out there. That is the point where remote operation stops being a hobby project and becomes a responsibility.

Security

A station reachable over the Internet is a transmitter somebody else could key. Treat it accordingly.

The short version: no open ports. Everything goes through a VPN or overlay network, and that means everything, including the camera and the web interface of the power strip. Those devices in particular are rarely built for a hostile network and often go years without firmware updates.

Then the usual obvious things that nonetheless need saying: unique passwords rather than reused ones, two-factor authentication where available, regular updates to the operating system and the VPN server. For monitoring, something small like Uptime Kuma is enough to tell you when the station stops answering. That is worth more than it sounds: you do not want to discover on Friday evening that nothing has been running since Tuesday.

If HAMNET is within reach, the whole connection path can be thought about differently. How that network is built is covered in HAMNET in Austria.

The legal position in Austria

Our earlier version was imprecise here, so let us go through it properly.

Remote operation is explicitly provided for in Austria. The TKG 2021 defines a remote station in § 3 Z 44 as "eine Amateurfunkstelle, die von einem Funkamateur fernbedient wird", an amateur station operated remotely by a radio amateur. And § 78a Abs 1 Z 5 records that "im Fall einer Remotefunkstelle die persönliche Anwesenheit des Inhabers der Bewilligung nicht erforderlich ist", meaning the licence holder need not be physically present. That is the decisive clause, because presence would otherwise be the sticking point.

The competent authority is the Fernmeldebüro, not the RTR. We got that wrong previously. The RTR handles plenty in the telecoms field, but amateur licences go through the Fernmeldebüro at fb.gv.at.

The Amateurfunkverordnung itself, correctly abbreviated AFV rather than AFU-VO, contains nothing specific on remote operation. What it does contain and what matters to us: § 5 Abs 1 ties the digit in the call sign to the federal state of the fixed location named in the licence. Remote shutdown capability is regulated in §§ 32 and 38, but for beacons and repeaters. And § 12 permits linking amateur stations by Internet technology within a narrow frame, namely for testing new transmission techniques. That is a different thing from accessing your own station, and the two get confused often.

In practice: it is the location of the transmitting equipment that constitutes the station, not where you happen to be sitting. If the radio is in Carinthia and you are in Hamburg, an OE8 station is on the air. Exactly what your licence requires for additional locations is best settled directly with the Fernmeldebüro before you build, not afterwards. We summarised the wider legal framework in Amateur radio legislation in Austria.

Remote in contests: read the rules

Logs get disqualified here regularly because somebody did not read the rules. In CQ WW, remote operation is permitted, but under a clear condition: the physical location of all transmitters, receivers and antennas must be at one station location. Remote receivers outside that location are not permitted. Category and licence limits apply unchanged.

So what does not work is monitoring your own signal through a WebSDR in Scandinavia while your antenna in Carinthia transmits. Individual contests do know tightly bounded exceptions. In CQ 160, for Single Operator Assisted, exactly one remote receiver within 100 kilometres of the transmitter site is allowed. Rules like these change, so the plain advice is to read the current rulebook before the contest.

Without a station of your own: the DARC remote stations

Worth mentioning because many people do not know it exists: the DARC runs a network of remote stations that members can use through a client program. A map shows which station is currently online. The requirements are DARC membership and a Class A licence; each session is limited to 60 minutes, after which you simply log in again.

For operators with no antenna options of their own, that is a realistic way of getting on the bands at all, and for everyone else a good chance to try remote operation before spending money.

https://www.youtube.com/watch?v=QBzvznkDhXM

Remote Radio, Connecting the World: a German-language overview (DL2YMR, DE)

The order to do it in

On your own LAN first. Radio, computer, software, all in the house. If it is not clean there, it will not improve across the Internet.
Then the tunnel. Set up Tailscale or WireGuard and check that you can reach the station from a mobile network. Only once that stands does radio come back into it.
Then the fallback layer. Power strip, UPS, watchdog. Before the station moves to its final site, not after.
Only then move it. And test everything again at the new site, including a deliberately induced power failure. Pull the plug and see whether it all comes back up by itself.
Document it. IP addresses, ports, credentials, cabling, all on one page. At the moment you need it, you will be somewhere else with no access to the very box you would have to describe.

Conclusion

Remote operation is no longer an exclusive subject. With wfview, a Raspberry Pi and Tailscale, a working setup costs under a hundred euros in extra hardware, provided the transceiver speaks CAT. The expensive solutions buy you convenience and integration, not fundamentally more capability.

The real hurdles sit somewhere other than most people expect. They are not in the software but in the network, CGNAT above all, and in the question of what happens when you are not there. Plan the power strip and the watchdog in from the start and you have a station that runs. Save them for later and you have a project that keeps putting you in the car.

73 – your oeradio.at editorial team

Transparency notice

This article was researched and written with AI support (Claude, Anthropic) and revised on 21 September 2026. Sources included the wfview manual, the FlexRadio helpdesk, product documentation from Icom and Kenwood, the ÖVSV wiki on the framework for remote stations in Austria, the statutory texts in the RIS, the CQ WW rules and the DARC remote station project. The title image shows an antenna installation in a residential area (photo: Wikideas1, CC0, via Wikimedia Commons); the further photographs also come from Wikimedia Commons and are credited at each figure. Editorial responsibility and review rest with the oeradio.at team. We accept no liability for accuracy or completeness; legal questions in individual cases are for the Fernmeldebüro. Corrections and additions, from operators of their own remote stations too, are welcome at kontakt@oeradio.at.

Der Beitrag Remote Shack: Control Your Amateur Radio Station from Anywhere erschien zuerst auf OERadio.

Stealth Antennas for Apartments and HOAs: Invisible Operation

Michael | OE8YML — Sat, 12 Sep 2026 07:00:00 GMT

There are two kinds of radio amateurs without an antenna. Those who are not allowed one, and those who do not dare to ask. Both end up at the same question: how do you run a station without anything visible on the building.

This article sorts the subject into three layers, deliberately in this order: what the rules say, what physics allows, and what it costs in performance. That third layer tends to get skipped, and it is exactly why some people are happy with an invisible antenna while others give up after six months.

The normal case in Austria: apartment building, balconies, a management company, no outdoor antennas. The rotary clothesline in the garden, by the way, is a serious antenna support. Photo: Johann Jaritz, CC BY-SA 4.0, via Wikimedia Commons.

Rules first, soldering iron second

Austria: tenancy law, condominium law, building law

For tenants, Section 9 of the Tenancy Act (MRG) is the relevant provision. It obliges the landlord to tolerate certain alterations provided they match the state of the art, serve an important interest of the tenant and do not harm legitimate interests. The explicit antenna privilege in § 9 para 2 no 5 covers radio and television reception only, so a transmitting antenna has to take the general route. The decisive lever is the two-month deadline: if the landlord does not object after being notified, consent is deemed given. The Supreme Court has also made clear that this creates no right to a particular mounting location. The paragraphs, the deadlines and a template letter are laid out in antennas and tenancy law in Austria. The landlord gets a say in where the thing goes, and that is exactly where the negotiation starts.

In condominium ownership the situation is stricter. Anything mounted on common parts of the building, so the roof, the façade or the outer wall of a balcony, is an alteration requiring the consent of the other owners or, failing that, a court decision. Inside your own four walls that does not apply, which is why the indoor antenna is often the shortest route for owners.

On top of that comes regional building law. In Vienna, antennas outside heritage zones need no permit, while inside such a zone any change to the external appearance does. If you live in an old building in a town centre, find that out before drilling rather than after.

One distinction that constantly gets blurred: receiving is legally easier than transmitting. The well-known satellite dish decisions rest on freedom of information, and that covers reception. Nothing follows from them for a transmitting antenna.

The practical advice from many cases: ask in writing, start small, promise removal without traces, attach a photo mock-up, and do not make power levels the topic before anybody asks. A three millimetre wire running from the terrace to the spruce is perceived differently from „an amateur radio installation".

USA: HOAs, CC&Rs and a law that never arrives

The term stealth antenna comes from the USA, and the situation there is different. Millions of homes sit in developments governed by a Homeowners Association whose private covenants, the CC&Rs, simply forbid visible antennas. Three points, because they are regularly confused:

PRB-1, the well-known FCC requirement for „reasonable accommodation" of amateur antennas, binds public authorities. It does not reach private contracts between owners.
The FCC's OTARD rule protects antennas for television reception, satellite and fixed wireless broadband against such clauses. Amateur radio antennas are not covered.
The Amateur Radio Parity Act was meant to close that gap and failed. Its successor, the Amateur Radio Emergency Preparedness Act, has been sitting in the 119th Congress as H.R. 1094 and S. 459 since February 2025 and has not been enacted.

For readers in Europe this mainly explains why half the literature on the topic is American, and why the flagpole plays such a starring role: in an HOA neighbourhood a flag is welcome and an antenna is not.

The American classic: what looks like a flagpole from the street is electrically a vertical with radials under the lawn. Photo: Noah Wulf, CC BY-SA 4.0, via Wikimedia Commons.

What invisibility costs physically

A hidden antenna is almost always a worse antenna. That is no reason to skip it, but it is a reason to calibrate expectations first. The losses come from four sources:

Attenuation by building materials. Tiles, wood and dry plaster cost little, often one to three decibels. A metal roof, a foil-backed insulation membrane or reinforced concrete are effective shields. Modern insulation is particularly treacherous: you cannot see the foil once the cladding is up.
Shortening and loss resistance. A 40-metre wire folded into five metres has a low radiation resistance. Everything that adds loss resistance, coils, joints, damp walls, comes straight off the efficiency.
Proximity to conductive parts. Gutters, heating pipes, rebar, cable trays. They detune, couple and radiate along, usually not in the direction you wanted.
Noise floor. Indoors the antenna sits inside the noise source. Power supplies, LED lighting, PV inverters and powerline adapters are a few metres away, see our EMC guide.

As a rough field figure: the same length of wire in the attic rather than outdoors costs one to two S-units. That is annoying, but only rarely is it the difference between „hard work" and „impossible".

The part no guide likes to mention

Transmitting indoors puts the antenna close to people who live there permanently. Exposure limits exist for assessing that, and they apply to your own family in the next room too. Three points worth taking seriously:

Distance is the most effective measure. An attic above a bedroom is a different matter from a loop on the desk somebody sits at.
Reducing power costs surprisingly little. From 100 to 10 watts is 10 dB, just under two S-units. In FT8 that is often the difference between decoded and decoded.
Magnetic loops carry very high voltage at the tuning capacitor. Even at low transmit power. A loop does not belong where children can reach it.

And since it belongs here: an antenna in the attic does not make lightning protection a smaller topic. The cable still enters the building, and the external protection system of the house does not want to be bypassed.

Solutions indoors

Wire in the attic

If an attic is available and the roof is not sheet metal, a strung wire is the best invisible antenna you can get. Two forms have proven themselves:

Dipole or inverted V, as high as possible under the ridge, fed through a common-mode choke. For 20 metres the length just about fits in many houses; for 40 metres you fold it.
End-fed half wave with a 49:1 transformer, run in a zigzag, see our article on the EFHW. Advantage: the feed point sits where the cable arrives anyway. Drawback: the far end carries high voltage, so do not staple it to a rafter somebody reaches past.

One practical point: common-mode current is not a side issue here, it is the main problem. A wire inside the house couples strongly into the domestic wiring. A proper choke at the feed point and a second one at the transceiver save a lot of grief, see baluns and ununs.

Magnetic loop

The loop is the classic apartment antenna and in practice a compromise with a clear profile. It needs little space, is noticeably quieter on receive than a wire because it responds to the magnetic field, and it can be rotated to null out an interferer. In exchange it is extremely narrowband, needs retuning after every QSY and reacts to anything conductive nearby. Details in our article on the magnetic loop.

One variant that gets mentioned too rarely: loop for receive only, wire for transmit. You do not have to do both jobs with the same structure.

Balcony and window frame

A surprising amount works on a balcony once you adjust which bands you expect. A shortened vertical with two to four tuned radials along the railing, a three metre fibreglass mast extended only while operating, or a wire strung from the balcony to a tree in the evening and pulled back in the morning. For the background see vertical antennas.

About the railing itself: a metal railing is a usable counterpoise but a miserable radiator. Using it as an antenna distributes RF throughout the building.

Solutions outdoors that nobody notices

Thin wire. Enamelled copper wire of 0.4 to 0.8 millimetres is invisible from ten metres away. It is mechanically marginal, so every end needs a bungee as strain relief. Grey or black instead of bright copper does the rest.
Rotary clothesline and washing line. A perfect support that is already approved, because nobody perceives it as an antenna mast.
Flagpole. Fibreglass mast with a wire inside, radials under the lawn or in the gravel. The standard recipe in the USA, over here mainly interesting in housing estates with strict development plans.
Fence and hedge. A wire along a wooden fence or inside a hedge is inconspicuous but couples heavily into the ground. It works and it costs efficiency.
Gutters and downpipes. Popular, but handle with care: contact resistance at the joints creates rectifier effects and therefore interference, and the gutter carries RF exactly where you do not want it.
Antenna only while operating. The most honest solution when the legal situation is tight. A wire thrown up for two hours in the evening is a different thing from a permanent installation, both in the neighbours' perception and in a management company's assessment.

Operating: making much out of little

Mode beats power. FT8 and CW work 15 to 20 dB below SSB. With a compromise antenna that is the difference between a contact and noise. If you have only ever done SSB, this is the biggest lever available, see also QRP operating.
Measure first, believe later. A NanoVNA tells you in ten minutes whether your attic wire is resonant or whether the tuner is merely flattening the meter. On that subject, our article on antenna tuners applies: it repairs the reading, not the power budget.
Short, decent cable. With an already lossy antenna, poor coax is a second loss stacked on the first, see the coax comparison.
WSPR as a measuring instrument. Two nights of WSPR at five watts show in black and white what the antenna can do, and produce a map that you need not show the management company but that keeps your own motivation alive.
Change location. No contradiction to the stealth idea: if you are restricted at home, move the loud operating outdoors. SOTA and POTA exist for exactly this situation, while the quiet home station handles FT8 and the evening net.

Videos on the topic

https://www.youtube.com/watch?v=CJr1qh1S7Es

A tour of a complete attic antenna farm, HF through UHF (HOA Ham)

https://www.youtube.com/watch?v=1mbwGan8pOE

A flagpole as an antenna support, build and operation (HOA Ham)

https://www.youtube.com/watch?v=cYd0l-PEPR8

Magnetic loop in the attic, an honest test with measurements (HamRadioConcepts)

Where to start

Situation	First attempt
Owned house with attic, tiled roof	Wire under the ridge, dipole or EFHW with a common-mode choke
Rental flat, balcony, reasonable landlord	Vertical with radials on the railing, extended only while operating
Rental flat, no balcony, high noise floor	Magnetic loop at the window, optimise receive separately
Terraced house with garden, strict neighbours	Thin wire to the clothesline or the tree, painted grey
Metal roof or reinforced concrete	No indoor antenna; use the balcony, the garden or portable operating
HOA neighbourhood in the USA	Flagpole, attic, thin wire, and read the CC&Rs first

Every row carries the same footnote: settle the legal side before you drill.

The conclusion is a sober one. An invisible antenna is a compromise and stays one, however clever the construction. But it is the difference between a hobby that happens and a callsign that sits in a drawer. Most people who go down this road report the same thing: the first wire is too short, the second too visible, and the third has worked for years without anybody in the building knowing about it.

73 – your oeradio.at team

Transparency Notice

This article was researched and written with AI assistance (Claude, Anthropic). The content was reviewed by the oeradio.at editorial team. The legal notes are orientation, not legal advice: Section 9 MRG and the regional building codes for Austria, the FCC rules PRB-1 and OTARD plus H.R. 1094 and S. 459 of the 119th Congress for the USA, as of September 2026. Corrections are welcome at kontakt@oeradio.at.

Der Beitrag Stealth Antennas for Apartments and HOAs: Invisible Operation erschien zuerst auf OERadio.

LoRa Gateway with an Amateur Radio Licence: Bridging RF and IP Networks

Michael | OE8YML — Thu, 10 Sep 2026 07:00:00 GMT

LoRa devices carry messages over kilometres, but somewhere that RF traffic has to cross into an IP network: the internet, HAMNET or a map. That is what a gateway does. Holding an amateur licence lets you do more than an ISM user, although not quite what is often claimed.

This article covers the gateway types, what the licence really gives you in legal terms, which hardware and software are current, and why the site decides between success and disappointment. For the wider mesh picture, see our comparison of MeshCom and Meshtastic.

What separates a gateway from a node

A LoRa gateway bridges the radio interface and an IP network. It receives LoRa packets and passes them on via Ethernet, Wi-Fi, HAMNET or cellular, and the other way round. An ordinary node only talks within the mesh, with no path to the outside. The gateway is what couples local RF islands into a larger network.

Four variants matter in an amateur radio context:

MeshCom gateway: bridge between the MeshCom mesh and HAMNET or the internet, a project from the Austrian community
Meshtastic MQTT gateway: connects a Meshtastic mesh to the internet over MQTT
LoRa APRS iGate: picks up APRS packets and feeds them into APRS-IS
LoRaWAN gateway: the classic eight-channel IoT box talking to a network server such as ChirpStack or The Things Network. It belongs in the ISM band, and the reason follows below

The regulatory picture, honestly counted

LoRa can be operated two ways in Europe, and the differences are large. Just not large in every respect the way many guides suggest.

Licence-free ISM operation

868 MHz: 25 mW ERP with a one percent duty cycle across 868.0 to 868.6 MHz where most LoRa channels sit, meaning 36 seconds of transmit time per hour. Other sub-bands have their own figures, 869.4 to 869.65 MHz for instance allows ten percent
433 MHz: 10 mW ERP and a ten percent duty cycle under ERC Recommendation 70-03 for short-range devices
Encryption: permitted and normal
Licence: none required, but no protection from interference either

70 cm with an amateur licence

Power in Austria: 200 watts for licence class 1 on 430 to 439.1 MHz. One kilowatt exists only with power level B or C and exclusively for EME and meteor scatter using a Yagi of at least 15 dBd gain. Details in our article on the frequency utilisation ordinance
Duty cycle: no restriction, continuous operation is allowed
Antennas: free choice, gain and height are not an approval issue because it is not the radiated power that is capped as in the ISM band
Encryption: not permitted, all transmissions must be readable
Callsign: mandatory, every station identifies

Now the reality check you rarely read. Those 200 watts are practically meaningless. An SX1262 module, the chip inside every Heltec or LILYGO board, delivers about 22 dBm at most, roughly 160 milliwatts. Even modules with a built-in amplifier reach one watt. Transmitting LoRa at 200 watts would require a linear amplifier for a constant-envelope signal, and nobody does that. The real benefit of the licence lies elsewhere: no duty cycle, no 10 mW ceiling, free choice of antenna.

The second misconception concerns interference. The range 433.05 to 434.79 MHz is an ISM band and sits entirely inside the 70 cm amateur allocation. That is precisely where MeshCom operates on 433.175 MHz and LoRa APRS on 433.775 MHz. You share those frequencies with wireless thermometers, weather stations, garage door openers and headphones. The licence grants more rights there, but not cleaner spectrum. Genuinely protected amateur spectrum would mean moving above 434.79 MHz or below 433.05 MHz, which neither the available hardware nor the established networks are set up for.

Height beats power: a lattice mast carrying several LoRa gateways and omnidirectional antennas. For coverage this site is worth more than any amplifier stage. Photo: Fabian Horst, CC BY 4.0, via Wikimedia Commons.

LoRaWAN does not belong under your licence

This deserves a clear statement, because the opposite circulates widely. LoRaWAN encrypts by design. Every packet carries AES-128 encryption of the payload using the AppSKey plus integrity protection with the NwkSKey. It cannot be switched off, it is part of the specification. Encrypted transmissions are not allowed in the amateur service.

It follows that LoRaWAN, The Things Network and ChirpStack are ISM technology. You run them on 868 MHz at 25 mW with a one percent duty cycle and no licence at all. If you want your own sensors on amateur frequencies, you do not use LoRaWAN, you use raw LoRa with an open protocol: MeshCom, Meshtastic in licensed mode, or a small packet format of your own.

MeshCom: the Austrian network

MeshCom is the network with the strongest amateur radio focus in the German-speaking countries, carried by the ÖVSV community and the Institute of Citizen Science. The essentials:

Frequencies: 433.175 MHz for messaging, 433.775 MHz for position reports
Firmware: an independent development maintained under icssw-org on GitHub, currently the 4.x line, latest release v4.35s from 3 September 2026
Encryption: none, the PSK is set to NONE deliberately, which is what the amateur rules require
Hardware: LILYGO T-Beam, LILYGO TTGO LoRa, Heltec LoRa 32, RAK WisBlock 4631, in other words ESP32 or nRF52 with a LoRa chip
Gateway link: the gateway speaks the APRS protocol to a MeshCom server, over HAMNET or the internet
Overview: which nodes and gateways are currently up is shown on the dashboard at meshcom.oevsv.at

Building one takes a supported board, the MeshCom firmware, a callsign and a site with Wi-Fi or HAMNET access. Configuration runs through the built-in web interface.

Meshtastic in licensed mode

Meshtastic is the larger international ecosystem and ships configured for ISM use. For amateur operation it has a dedicated switch that you need to know about.

A Meshtastic node showing its configured region on the display, here EU_868. For 70 cm operation this needs to read EU_433, otherwise the device transmits in the wrong band. Photo: -stk, CC BY-SA 4.0, via Wikimedia Commons.

The key points for licensed operation:

Set region EU_433. After a factory reset the device lands on slot 4 at 433.875 MHz in that region
Know the factory limits. For EU_433 the firmware itself caps output at 10 dBm and enforces a ten percent duty cycle, calculated every minute over a rolling hour. Those are ISM constraints in software, not amateur regulations
Enable HAM mode. The documentation is explicit: if you operate under a licence, enable HAM mode and turn encryption off. With is_licensed set, the firmware lifts its power limits
Put your callsign in the long name. That satisfies identification
Check the PSK yourself. Do not assume the key disappears automatically, open the channel settings and clear it if it is still there

You turn this into a gateway by enabling the MQTT module on a board with Wi-Fi, entering a broker and allowing uplink and downlink on the channel. Optionally, "map reporting" registers the device on the global map.

LoRa APRS iGate

An iGate receives LoRa APRS packets on 433.775 MHz and forwards them to APRS-IS so the stations appear on sites such as aprs.fi, with no classic TNC and no 1200 baud packet involved. The widely used firmware comes from CA2RXU and runs on LILYGO T-Beam or Heltec boards. Flashing happens through a web flasher in the browser, configuration through a built-in web page for callsign, Wi-Fi and APRS-IS credentials.

With a decent rooftop antenna such an iGate hears packets from 30 to 50 kilometres away, considerably more from a summit. Here too, operating on 433.775 MHz is amateur radio and requires a licence.

What about MeshCore?

MeshCore is the third large mesh ecosystem and currently the fastest growing one in Austria, carried among others by the Carinthian CarinthiaMesh initiative. Technically it forwards traffic differently from Meshtastic: only fixed repeaters relay packets, handhelds merely transmit and receive. That produces noticeably less background traffic, but it needs people who put repeaters in good places. How fast that can go is documented in our report on 32 sites in two weeks.

For this article one point decides everything: MeshCore runs in the 868 MHz ISM band and uses encryption. Channel keys are derived from the channel name and direct messages are end to end encrypted. Exactly like LoRaWAN, that makes it unsuitable for the amateur band and firmly licence-free operation at 25 mW with a duty cycle. That is not a shortcoming, it is a different goal: MeshCore wants to work without an exam and without a callsign.

In practice the split is clean. If you want a gateway with licence privileges, you end up with MeshCom or Meshtastic in HAM mode on 70 cm. If you want a network for everyone, including neighbours without a licence, you put up a MeshCore repeater on 868 MHz. The same board does both, the decision happens at flashing time, and plenty of radio amateurs simply run two devices. Which nodes are active nearby is shown for Meshtastic on our Meshmap.

Hardware: small, medium, large

Single-channel boards are entirely sufficient for MeshCom, Meshtastic and LoRa APRS, because these networks use one fixed frequency:

Heltec LoRa 32 V3: compact with an OLED, the classic for a fixed gateway with an external antenna
LILYGO T-Beam: ESP32 with GPS and an 18650 holder, handy if the device should report positions too
RAK WisBlock 4631: an nRF52 platform with very low idle current, first choice for solar. Paired with the RAK13800 Ethernet module it is also the common route to a gateway on a cable rather than Wi-Fi

Eight-channel gateways such as the RAK WisGate or Dragino LPS8 are LoRaWAN hardware for the ISM band. The amateur networks do not need them.

Homebrew gateway with a Raspberry Pi, concentrator board and PoE splitter in an IP-rated enclosure. The layout comes from the LoRaWAN world, but the packaging idea works for any outdoor gateway. Photo: Fabian Horst, CC BY-SA 4.0, via Wikimedia Commons.

Site beats everything

LoRa on 433 MHz behaves largely like line of sight. Buildings, hills and wet forest attenuate hard, and no software setting compensates for that. The dominant parameter is antenna height, and nothing else comes close.

One Fresnel zone rule of thumb gets misquoted constantly. The radius of the first Fresnel zone at mid path is

r ≈ 8.66 · √(D / f), with D in kilometres and f in gigahertz.

On 433 MHz that gives roughly 13 metres at 1 kilometre, about 29 metres at 5 kilometres and around 42 metres at 10 kilometres. Anyone quoting 13 metres for a ten kilometre path is planning three times too optimistically. In practice keeping about 60 percent of that zone clear is enough, but a stand of trees directly in the line still costs noticeable signal.

Free tools are plenty for planning: HeyWhatsThat shows which horizons are visible from a point, and the MeshCom and Meshtastic maps reveal which nodes are actually active nearby.

Antenna, cable, enclosure

The stub antenna on the board is unsuitable for a fixed gateway. An external antenna is the most effective investment you can make:

Collinear omni with 5 to 8 dBi: the gateway standard, usually 0.5 to 1 metre long
Homebrew ground plane: a quarter-wave radiator of about 16.5 centimetres for 433 MHz plus four radials, material cost near zero
Yagi: for fixed point-to-point links between two sites, with useful gain and a clear preferred direction

Cable follows the usual UHF rules: keep it short, and at 433 MHz use RG-58 only for a couple of metres. Longer runs deserve Aircell 7, Ecoflex 10 or LMR-400, see our coax comparison. Two metres of thin cable eat more than most people expect, and reception suffers just as much as transmit power.

Building a weatherproof outdoor node: fibreglass omni, short jumper cable, electronics in a junction box with cable glands, plus a connector for a solar panel. Photo: -stk, CC BY-SA 4.0, via Wikimedia Commons.

Power

PoE: the elegant rooftop answer, one cable for power and network. The small boards have no PoE input, so a splitter to USB for a few euros does the job. If you want Ethernet at the node itself, combine a RAK4631 with the RAK13800
Mains adapter: perfectly adequate indoors, an ESP32 gateway draws under a watt
Solar: for remote sites. An nRF52 board such as the RAK4631 with a small panel and a LiFePO4 cell runs autonomously through winter, while a Raspberry Pi gateway at three to five watts needs a much larger panel and more battery

For summit sites the combination of panel, charge controller and LiFePO4 is the proven route, because those cells tolerate cold better than lithium-ion.

What is running in Austria

MeshCom: gateways on summits and at club sites, densest in Upper Austria, Styria and Tyrol. Current status is visible on the dashboard
LoRa APRS: numerous iGates on 433.775 MHz, visible on aprs.fi
HAMNET as the backbone: many gateway sites hang off HAMNET rather than commercial internet and stay reachable through provider outages
TTN: in the ISM band, mainly around Vienna and Lower Austria, for IoT sensors without a licence
AREDN: combined at some sites, LoRa for narrowband messaging, AREDN for the wideband IP link

If you want to see your own traffic rather than just read it: a WebSDR lets you follow LoRa packets in the waterfall and even decode them, described in our article on LoRa mesh in OpenWebRX+.

Practice that has proven itself

Antenna before power. Three more metres of height beat any firmware setting
Respect airtime. Amateur radio has no duty cycle, but the mesh itself certainly has a capacity limit. Short telemetry intervals and generous hop limits will choke a network that runs fine with sensible values
Plan lightning protection. A rooftop antenna means bonding and a surge arrestor in the coax, not an optional extra
Build for weather. IP65 enclosure, cable glands, a drip loop. Water finds every opening
Plan for remote maintenance. Nobody wants to climb to the roof for a firmware update, so allow for Wi-Fi coverage or OTA updates
Verify callsign and plain text. Before leaving it running, check that encryption really is off and the callsign is being sent

Videos on the topic

https://www.youtube.com/watch?v=aWtqm7lbYoo

MeshCom as a messaging network built by and for radio amateurs (Tech Minds)

https://www.youtube.com/watch?v=43FD9CvXjh0

Configuring and testing a LoRa APRS iGate and tracker (Tech Minds)

https://www.youtube.com/watch?v=5TZV3sjkJAc

LoRa APRS in practice: iGate and digipeater side by side (Radiohyperactivity, LB5JJ)

Your first gateway

Pick hardware: Heltec LoRa 32 V3 for an easy start, RAK4631 for solar, plus the RAK13800 if it should be Ethernet rather than Wi-Fi
Get an antenna: a 433 MHz omni with 5 dBi, matching cable and surge protection
Flash firmware: MeshCom, Meshtastic or the LoRa APRS iGate build, depending on the target network, all via web flasher in the browser
Configure: enter your callsign, set region EU_433 or the MeshCom frequency, encryption off, gateway mode on
Mount it: as high as possible, with a clear view towards where traffic is expected
Verify: check the dashboard or aprs.fi to confirm the gateway appears and is passing packets

For around 60 euros you have a working gateway on the roof, and every additional gateway improves coverage for everybody nearby. That is the actual appeal: you are not only building for yourself, you are building a network that only exists collectively.

73 – your oeradio.at team

Transparency Notice

This article was researched and written with AI assistance (Claude, Anthropic). The editorial team reviewed and edited all content. Power figures come from the Austrian frequency utilisation ordinance, network data from the ÖVSV wiki and the MeshCom project. Corrections are welcome at kontakt@oeradio.at.

Der Beitrag LoRa Gateway with an Amateur Radio Licence: Bridging RF and IP Networks erschien zuerst auf OERadio.

Antenna Tuners: Manual vs. Automatic — Which Is Better?

Michael | OE8YML — Mon, 07 Sep 2026 07:00:00 GMT

Few pieces of gear in the shack are as widely misunderstood as the matching unit. Everybody calls it an antenna tuner, and the name is the first thing that misleads: the antenna is not being tuned at all, it stays exactly as good or as bad as it was. What gets tuned is what the finals see.

This article sorts the topic out: what is inside the box, where the power actually goes, why the feedline matters more than the tuner itself, and when the manual classic beats an automatic unit. If you want the underlying matching theory first, read our article on baluns and ununs.

What a tuner does, and what it does not

A matching unit is an adjustable LC network. It transforms the complex impedance arriving at the end of the feedline into a real 50 ohms for the transceiver. The power amplifier sees a clean load, does not fold back and does not go into protection. That is the entire purpose.

What does not happen: the efficiency of the antenna is unchanged. A wire that is too short stays a wire that is too short. The mismatch between tuner and antenna remains, standing wave included. The tuner moves the place where the problem ends, it does not solve it.

The second common misconception is about the meter. SWR 1.0 at the rig is not a quality statement about your antenna system, only about the load at the transmitter output. A 50 ohm dummy load reads 1.0 as well and radiates nothing. If you want to know what the antenna is really doing, measure at the feedpoint, for example with a NanoVNA.

What is inside the box

Practically every matching unit is built from two or three adjustable components, classically a coil and a capacitor. The topology decides matching range and losses:

L network: one coil, one capacitor. The lowest-loss arrangement, typical insertion loss around 0.1 to 0.3 dB. The drawback: it only matches in one direction, depending on whether the load is above or below 50 ohms.
T network (CLC): two variable capacitors with a coil between them. The classic in almost every commercial manual tuner, because it matches everything from near short to near open. The price is ambiguity: there are several settings that produce SWR 1.0, and most of them are worse than the best one.
Pi network: familiar from valve transmitters, good harmonic suppression, but it needs large capacitances on the low bands.
Z-match: a resonant, link-coupled design with a balanced output, popular in the QRP scene and with open-wire feed because it covers several bands without switching.

A manual matching unit from the inside: air variable capacitor, coil, cross-needle meter. The knobs are labelled R TUNE and X TUNE, because that is exactly what you set, the real and the reactive part of the load. Photo: Pindari, CC BY-SA 2.5, via Wikimedia Commons.

Automatic tuners use the same networks, except relays switch fixed steps of capacitance and inductance. A microcontroller works through the combinations and stores the result, so the next band change needs no search run.

Same job, different construction: an automatic tuner switches fixed steps of toroidal inductors and capacitors with relays. Those toroids also set the power limit, which is why such units rarely go beyond 200 watts. Photo: Adamantios, CC BY-SA 3.0, via Wikimedia Commons.

The price of matching

Every match costs power, and more of it than most people assume. Close to a match, a decent tuner has an insertion loss below 0.3 dB, which is negligible. Under extreme mismatch, 2 to 4 dB are possible, and then half to two thirds of your output stays in the box as heat.

The physics is quickly explained. Into a very low impedance, say 3 ohms with a substantial reactive part, the same power means four times the current compared with 50 ohms. Loss in the coil wire rises with the square of the current, so by a factor of 16. That is exactly why a tuner gets hot when it has to match a short wire on 80 metres.

The T network adds a quirk worth knowing. Because several settings produce SWR 1.0, the first dip you find is not automatically the best one. The practical rule: look for the solution that keeps the capacitances as large as possible, with at least one capacitor near its end stop. If a match is only possible with both capacitors near mid scale, tuning becomes sharp, Q goes up and dissipation rises noticeably.

The corresponding workshop test is unglamorous but effective: after a few minutes of operating, take the lid off and touch the coil. Too hot to touch means a serious part of your output is staying in the matching unit. In one comparison on a doublet with 300 ohm feeder, a built-in automatic tuner was at least 3 dB worse than the best unit in the group on four bands, which at 100 watts means at least 50 watts of heating in the shack.

The bigger lever is the feedline

Anyone discussing tuner losses while ignoring the feedline is optimising the wrong end. On a mismatched line, forward and reflected waves travel through the cable repeatedly, and every pass costs attenuation. The table below works this through for 30 metres of cable on 20 metres, based on the figures from our coax comparison:

30 m feedline, 14 MHz	SWR 1:1	SWR 3:1	SWR 5:1	SWR 10:1	SWR 20:1
RG-58	1.5 dB	2.1 dB	2.9 dB	4.5 dB	6.6 dB
RG-213	0.5 dB	0.9 dB	1.2 dB	2.1 dB	3.5 dB
Ecoflex 10	0.4 dB	0.7 dB	1.0 dB	1.7 dB	3.0 dB
450 ohm window line	0.15 dB	0.25 dB	0.4 dB	0.7 dB	1.3 dB

Total loss including the additional loss caused by standing waves. At SWR 10:1, 100 watts into RG-58 arrives as 36 watts at the antenna, RG-213 delivers 61 watts and window line 85 watts.

Which is the real message of this article: a tuner in the shack repairs the meter reading, not the power budget. Running a multiband antenna through a long coax feeder at high SWR wastes power no matter how good the matching unit is. Two ways lead out of it, either a matching unit right at the feedpoint or a low-loss balanced feeder. For your own numbers with different lengths and frequencies, use our Kabelblick calculator.

Manual tuners

A manual tuner is an honest piece of engineering: roller inductor or tapped coil, one or two air variable capacitors, a cross-needle meter. None of it breaks, because none of it runs software.

Its strengths are high power and extreme loads. Air variables with proper plate spacing and a roller inductor of silver-plated wire handle voltages and currents that make a relay with a toroid give up long before. For a kilowatt and beyond, for open-wire feed and for antennas that sit very far from 50 ohms on individual bands, this is still the most robust solution.

The downside is the workload. Every band change means retuning, and if you change bands every ten minutes in a contest you lose time. In exchange you get something automatics do not provide: a feel for how sharp the match is and how far the antenna sits from resonance.

Homebrew Z-match with a balanced output: two air variables, a link-coupled coil on PVC tubing, a small transformer for the SWR bridge. Units like this are the classic partner for open-wire feed and portable operating. Photo: HuluPoika, CC BY-SA 4.0, via Wikimedia Commons.

One buying caveat since 2024 that many recommendation lists online still miss: MFJ ended production in Starkville on 17 May 2024, taking the Ameritron, Vectronics and Mirage brands with it. The antenna brands Hy-Gain and Cushcraft went to ITU Corporation in Indiana in April 2026 and continue there, but the classic MFJ tuners are essentially a used-market item now. Buying new today means Palstar, European makers such as Annecke for balanced matching units, or homebrew.

Automatic tuners

An automatic tuner takes the knob-twiddling off your hands. It measures, switches relays, finds a solution in one to three seconds and remembers it for that frequency. For multiband operating, for digital modes with frequent band changes and for portable work, it is the more practical route.

The limits are in the physics of the parts. Toroidal inductors and small relays cap the power, typically at 100 to 200 watts, while larger external units manage a kilowatt. Then there is heat: in continuous-carrier modes such as FT8 the tuner is heating all the time, not only between overs. The popular ATU-100, based on the open-source design by N7DDC, is rated 100 watts on paper, but practice suggests keeping FT8 nearer 50 watts so the small toroids do not overheat. It uses a 7x7 network of seven switchable inductors and seven capacitors, covers 1.8 to 50 MHz and starts its search at one to five watts of drive.

QRP has its own class of very small units. The Elecraft T1 covers 1.8 to 54 MHz, handles 20 watts SSB and CW or 10 watts in digital modes and matches loads to around 10:1 SWR, with reduced range on 160 and 6 metres. The Icom AH-705 for the IC-705 works at up to 10 watts, needs at least 30 metres of wire for 1.8 to 50 MHz or 7 metres from 3.5 MHz upwards, tunes in two to three seconds and stays below 2:1 afterwards. If you work with a handful of watts, our article on QRP operating gives the context.

Internal, external or at the feedpoint

Built-in tuners are convenient and take no space. Their catch range is deliberately small: the IC-7300 matches roughly 16.7 to 150 ohms, which is 3:1 SWR, and the FT-991A and most other rigs in that class are similar. For a resonant antenna with some bandwidth margin that is fine. For a random wire it is not. Some rigs also offer an emergency forced tuning mode that works outside the regular range, but that is not a permanent operating condition.

External tuners in the shack widen the range considerably, often to 10:1 SWR and beyond, and allow higher power. They change nothing about the loss on the line, see the table above.

Matching units at the antenna feedpoint are technically the cleanest solution. The coax runs matched, the extra loss disappears, and the matching happens where the impedance actually occurs. The Icom AH-4 and AH-705, the SGC units or a CG-3000 are built for exactly that: weatherproof housing, control over the coax, terminals for wire and counterpoise. Two things need planning, namely a proper radial system or counterpoise and enough distance from the shack. A random wire that starts right at the window reliably puts RF into your microphone, however good the tuner is. With small high-Q antennas such as a magnetic loop, the matching always sits at the antenna anyway.

Tuning it properly

Tune at low power. Ten watts in a carrier mode is enough for any tuner. Full power into a load that is not yet matched is the most common reason for burnt relay contacts.
Never tune through the amplifier. The PA belongs in bypass or standby while you tune. If the tuner sits behind the amplifier, it must be rated for its full output.
Measure first, tune second. If you know the feedpoint impedance, you know in advance whether the tuner can find a low-loss solution at all.
Keep the memories clean. After antenna changes, a new cable or a different location, clear the stored settings of an automatic tuner, otherwise it reuses an old and unsuitable solution.
On a T network, look for the large capacitance. Do not take the first dip, take the one with the capacitors meshed as far as possible.

Videos on the topic

https://www.youtube.com/watch?v=pdOEiML2XGk

What a matching unit does and does not do, with an eye on the feedline (HamRadioConcepts)

https://www.youtube.com/watch?v=JYlECCWTbCE

Hands-on: how to operate a manual antenna tuner (KB9VBR Antennas)

https://www.youtube.com/watch?v=tV8gi3N2o4Q

Manual versus automatic tuners compared in a real station (Coffee and Ham Radios)

What suits which station

Situation	Recommendation
Resonant mono- or multiband antenna, SWR below 3:1	The built-in tuner is enough, often you need none at all
Wire antenna on many bands, frequent band changes	External automatic tuner with memories
Portable, QRP, minimum weight	Small auto ATU or a homebrew Z-match
A kilowatt and beyond	Manual tuner with roller inductor, or a QRO-class auto tuner
Open-wire feed and true all-band operating	Balanced matching unit, Z-match or Annecke style
Long coax run, high SWR on some bands	Put the matching unit at the feedpoint, not in the shack
FT8 and other continuous-carrier modes	Reduce power and keep an eye on tuner heating

The most honest option is missing from the table: build an antenna that already sits near 50 ohms on your favourite band. Then the tuner handles the rest.

That is the summary, too. A tuner is no substitute for a suitable antenna, it is the tool that makes an existing antenna usable across more bands. Manual or automatic is less a matter of faith than a question of power level and convenience. The far bigger differences in the power budget happen elsewhere, in the choice of feedline and in the location of the matching. Get those right and you can pick the tuner itself to taste. How this plays out with different antenna types is covered in our article on vertical antennas.

73 – your oeradio.at team

Transparency Notice

This article was researched and written with AI assistance (Claude, Anthropic). The content was reviewed by the oeradio.at editorial team and prepared for the Austrian amateur radio community. The attenuation figures in the table are calculated from the cable data in our coax comparison. Corrections are welcome at kontakt@oeradio.at.

Der Beitrag Antenna Tuners: Manual vs. Automatic — Which Is Better? erschien zuerst auf OERadio.

Meshtastic, MeshCore and MeshCom in the waterfall: reading LoRa with OpenWebRX+

Michael | OE8YML — Sat, 05 Sep 2026 14:00:00 GMT

Until recently, finding out whether there is real mesh activity in your valley meant putting up a node and waiting. There is another way now: OpenWebRX+ decodes LoRa packets right in the browser, covering Meshtastic, MeshCore and MeshCom. You see the transmissions in the waterfall, you get the parameters of each transmission, and with Meshtastic you even get the content of the open channel.

On WebRX.at, the WebSDR run by OE8YML in Nötsch, this is set up and publicly accessible. This article explains what happens technically, which version you need, which settings have to match and where the limits are.

What it looks like: the range around 869.5 MHz in the waterfall, two bookmarks for the mesh networks, the mode selector on the right set to Meshcore, and the decoder pane on the left showing bandwidth, coding rate and spreading factor. Screenshot: WebRX.at, OE8YML.

What is actually happening

LoRa does not modulate like voice radio, it spreads the information across a frequency sweep called a chirp. That is exactly what makes the signal so recognisable in a waterfall: diagonal streaks in an otherwise quiet band. An ordinary receiver hears nothing useful there, because there is nothing to hear. It takes a decoder that unwinds the chirps.

OpenWebRX+ brings one along. The receiver slices the relevant channel out of the spectrum, a LoRa decoder reconstructs the packets, and for Meshtastic a parser on top unpacks the payload. The decoder pane then shows the bandwidth, coding rate and spreading factor each packet was sent with. Those values come out of the packet header, so they do not have to be known in advance.

You need the right version

This is where most attempts fail: plain OpenWebRX cannot do it. What you need is the fork known as OpenWebRX+, and even there the version decides. The project's public changelog shows when each piece arrived:

1.2.114: integration of the LoraRX tool from dxlAPRS, plus the LoRa WAN, LoRa APRS and FANET modes and, for the first time, Meshtastic and Meshcore.
1.2.115: MeshCom arrives as its own LoRa mode, along with predefined LoRa bands and frequencies.
1.2.116: the actual Meshtastic decoder that makes the payload readable, and a parser for LoRa APRS.

So if you want all three, you want at least 1.2.116. The station in Nötsch currently runs 1.2.123, which is the version shown in the status output at the bottom left of the screenshot above.

Frequencies and bandwidths

Meshtastic, region EU_868, LongFast preset: 869.525 MHz at 250 kHz bandwidth.
MeshCore in Europe: 869.618 MHz, commonly 250 kHz as well.
MeshCom in Austria: 433.175 MHz in the 70 centimetre amateur band, with 125 kHz bandwidth and a considerably higher spreading factor.

Meshtastic and MeshCore sit only 93 kHz apart and comfortably fit in the same SDR window. Even so they need separate settings, because the decoder depends on the correct centre frequency and mode. Tuning the Meshtastic channel and hoping to catch MeshCore along the way does not work.

One trap hides in the interface. In the decoder settings the bandwidth is offered as a list whose labels end in kbps. What is meant is kilohertz. The entry showing 250 is therefore the 250 kHz bandwidth that Meshtastic and MeshCore normally use in Europe, not a data rate.

Operating it in the browser

Pick a profile. The profile selector sits at the top of the receiver panel. A profile for the 868 MHz range puts the receiver straight at the right spot in the spectrum.
Set the mode. Below the classic modes the mode bar offers the digital decoders, among them Meshtastic, Meshcore and MeshCom.
Click a bookmark. If bookmarks are set in the waterfall, one click gets you both frequency and mode.
Check the bandwidth. The decoder settings have a section for LoRa messages where the bandwidth can be set per network. If it does not match the local network, the pane stays empty even though the waterfall clearly shows activity.

Usefully, the state travels in the link. To try it straight away at the station in Nötsch: MeshCore on 869.618 MHz and Meshtastic on 869.525 MHz. Both open the receiver right on the correct frequency, with the matching decoder and the squelch wide open. Behind the hash sit freq for the frequency in hertz, secondary_mod for the digital decoder, mod for the classic mode and sql for the squelch. To show a different network, swap frequency and decoder. That makes it easy to share exactly the view you are talking about in a net or a chat.

The decoder pane does not fill continuously, it fills packet by packet. Depending on activity there can be a long quiet spell between transmissions. If nothing shows up, wait and watch the waterfall first.

Updating, in broad strokes

Refresh the package index for that one source.
Check which version is available before installing anything.
Update OpenWebRX and the related libraries, usually the decoder libraries along with it.
The mesh modes need extra packages, among them the LoraRX tool from dxlAPRS and the Python binding for Meshtastic.
Restart the service and check the log to see that the SDR comes up cleanly and no errors appear for the new modes.

One experience that saves time: if apt stubbornly offers an old version, the cause is often not the repository but a stale local package index. A targeted refresh of exactly that source suddenly reveals the current version. It is equally worth resisting the urge to pull in every pending system update at once. Keeping the change small and traceable pays off, because a WebSDR that will not start after a sweeping upgrade costs far more time than the steps you saved.

Whether the new modes are actually available is shown on the software's status page, which lists the features it detected. If you are setting up your own server, the basics are in running your own OpenWebRX.

What it is good for

Proof that a node really transmits. If you put a solar node on a hill and wonder whether it is still alive, you see the transmission in the waterfall without going through the network.
Assessing a site before building. You can see which networks arrive from which direction before buying hardware.
Troubleshooting parameters. Because bandwidth, coding rate and spreading factor are displayed, you can check whether a node really transmits with the settings it is supposed to use.
Getting started without hardware. Anyone flirting with the idea can watch how much traffic there actually is. For getting started we have Meshtastic in practice, MeshCore and MeshCom. If you would rather start on the receiving side, RTL-SDR for beginners is the cheapest way in.

For Carinthia it is worth comparing with the map: how dense the network has become is visible on our Meshmap and in the report on the growth to 32 sites.

What has to be said honestly

Reading along calls for a word about confidentiality. The Meshtastic default channel is protected with a publicly known key, which in practice means it is not confidential. That is precisely why a WebSDR can display the content. Reading there is not illicit, it is using an open community frequency. The flip side applies to everyone transmitting: whatever goes out on the default channel is potentially there for all to see. Custom channels with your own key stay unreadable, and direct messages have additional protection in recent firmware.

With MeshCom the question is different. It runs in an amateur band where encryption is not permitted anyway and transmissions carry callsigns. Listening in is as normal as monitoring a repeater net.

Two technical limits apply as well. A WebSDR only hears what reaches its antenna, so the picture is always the one from the receiver's location and not from the whole network. And receiving is not participating: you cannot transmit this way, and joining still needs a node.

A final practical note: the bandwidth a network uses can differ regionally because it depends on the chosen preset. If the waterfall visibly shows traffic but the decoder pane stays empty, the bandwidth setting is almost always the reason, not reception.

Sources

OpenWebRX+ changelog, the basis for the version details on the LoRa modes
the project's package repository with installation notes
meshtastic.org, regions, presets and channel keys
ÖVSV wiki: MeshCom, frequency and parameters for Austria
WebRX.at, the station this setup is described from

73 – your oeradio.at editorial team

Transparency Notice

This article was researched and written with the support of AI (Claude, Anthropic) based on public sources and our own observation at the station described, and the content has been editorially reviewed. Version details come from the project's public changelog, frequency details from the project documentation and the ÖVSV wiki. Deliberately not included are configuration files, profile data and access details of the station, so the procedure is described in general terms and is not meant as a copy template. The lead image is a screenshot of our own station. Corrections welcome at kontakt@oeradio.at.

Der Beitrag Meshtastic, MeshCore and MeshCom in the waterfall: reading LoRa with OpenWebRX+ erschien zuerst auf OERadio.

Understanding Baluns and Ununs: Proper Impedance Matching

Michael | OE8YML — Sat, 05 Sep 2026 07:00:00 GMT

Few components in a shack are bought as often and understood as rarely as the balun. It is treated as a cure for poor SWR, for interference on the neighbour's television and for RF on the microphone. In truth it can fix only one of those three, and it does that one very well.

This article sorts the subject out: what a balun does and what an unun does, why the difference between current and voltage types decides between success and frustration, which ferrite mix suits which job, what the popular 49:1 on an EFHW really costs you, and how to measure all of it with a NanoVNA instead of taking it on faith.

The real problem: the third conductor

Electrically, coax has three conductors, not two. The centre conductor and the inside of the shield carry the wanted current. The outside of the shield is a conductor in its own right, and that is where the trouble starts. Feed something balanced like a dipole with it and part of the current returns along the outside of the cable towards the shack.

This common mode current is behind most of the complaints blamed on baluns: the feedline radiates, the pattern distorts, the SWR changes when you move the cable, the tuner suddenly finds different settings, RF appears on the microphone, the neighbour hears you in the speakers. Anyone hunting interference is chasing exactly this nine times out of ten.

Balun and unun, kept apart

Balun stands for balanced to unbalanced. It sits between something balanced, a dipole for instance, and an unbalanced feedline. A balun may also transform impedance, but it does not have to: the common 1:1 balun transforms nothing, it only provides a clean transition.

Unun stands for unbalanced to unbalanced. It joins two unbalanced systems and transforms impedance only. The typical case is the 9:1 for a random length wire, which is no fun at all without a proper counterpoise.

A wideband HF balun. The switch turns it into either a 1:1 current balun or a 4:1 voltage balun, which puts both designs discussed here into a single box. Photo: Elgull, CC BY-SA 4.0, via Wikimedia Commons.

Current balun or voltage balun

This is the distinction everything hinges on in practice, and it is printed on almost no packaging.

The voltage balun after Ruthroff forces equal and opposite voltages at its two outputs. That sounds sensible, but it only helps as long as the load really is balanced. As soon as one dipole leg runs closer to the roof than the other, as soon as the antenna turns reactive or is used off resonance, the currents divide unevenly and the remainder flows back along the outside of the cable. A voltage balun barely suppresses common mode current at all.

The current balun after Guanella forces equal and opposite currents instead. It lets the output voltages float and presents a high impedance to common mode current. That keeps it honest even when the antenna hangs asymmetrically, which in real gardens is the normal case.

Hence the rule of thumb worth remembering: when in doubt, current balun. If you need both impedance transformation and choking, put a 4:1 voltage balun and a separate 1:1 choke in series, or use a 4:1 built the Guanella way in the first place.

The ratios

What is quoted is always the impedance ratio, and that is the square of the turns ratio. A transformer with two turns against fourteen has a turns ratio of 1:7 and therefore an impedance ratio of 1:49.

1:1 for the dipole and anywhere the transition simply needs to be clean.
4:1 for loads around 200 ohms, such as folded dipoles and some delta loops.
9:1 for long wires and random wires in the few hundred ohm range, always with a decent counterpoise.
49:1 for the end fed half wave, which sits at roughly 2,400 to 3,000 ohms at the feedpoint.
64:1 as a variant of the same design when the measured feedpoint impedance comes out higher.

The common mode choke

A common mode choke is electrically a 1:1 current balun that does nothing except present a high impedance to common mode current. The wanted signal inside the cable does not see it, because its fields cancel inside the coax. Only the current on the outside meets the ferrite.

The decisive question is how much choking impedance is needed. Below 1,000 ohms not much useful happens. Several kilohms across the bands you actually use is a workable target. In practice that means eight to twelve turns of RG-58, RG-8X or RG-213 on an FT240 sized core, depending on mix and band.

Placement matters just as much. One choke belongs at the feedpoint. A second one at the shack entry is often the more effective of the two, because it stops the RF where it couples into equipment and mains wiring. To find out whether there is common mode current at all, measure it with a common mode indicator before buying ferrite.

Which ferrite

Toroids and clamp-on ferrites. The mix is not printed on the parts, so write it down when you buy. Photo: Elgull, CC BY-SA 4.0, via Wikimedia Commons.

Mix 31: first choice for common mode chokes from 160 through 10 metres, usefully effective across the whole range.
Mix 43: the decades-old classic, permeability around 800, choking impedance peaking roughly between 8 and 15 MHz. As common in transformers as in chokes.
Mix 52 and 61: sensible from about 10 MHz upwards and for builds aimed at the higher bands.
Powdered iron such as mix 2: low loss and suitable for high power transformers, but useless as a common mode choke because the permeability is far too low.

A widespread misconception is that more cores are always better. Two stacked cores double the impedance but also push the self resonance of the winding downwards. On 10 metres a choke with too many turns can perform worse than one with fewer.

Winding

Bifilar winding: two wires run side by side on a toroid. This is the basis of most balun and unun designs. Photo: Windell Oskay, CC BY 2.0, via Wikimedia Commons.

Transformers are wound bifilar, two wires in parallel, so the coupling stays as tight as possible. For the classic W1JR choke you pass the coax itself through the core instead, commonly two times five and a half turns of RG-58 on an FT140-43.

It also works without a core: the so-called ugly balun is a few turns of coax on a piece of pipe. It costs nothing but only works narrowband around the self resonance of the coil, and it is clearly inferior to a ferrite core. Fine as a field expedient, not as a permanent installation.

The 49:1 on an EFHW, honestly

No component has conquered as many shacks in recent years as the 49:1 transformer for the end fed half wave. It works, but it is not a magic trick, and the numbers are uncomfortably honest.

On 20 metres a monoband EFHW with a 49:1 on mix 43 runs with very low losses. On the higher bands from 17 through 10 metres, however, losses around 30 percent, roughly 1.5 dB, are well documented. The reason lies in the material itself, whose loss component rises noticeably above 10 MHz.

Two things help. Below 10 MHz a two-turn primary produces only about half the loss of a single-turn primary, which means considerably less heat at the same power. And duty cycle matters more than peak power: a small core forgives 100 watts of SSB, but not 100 watts of FT8 for hours.

Be careful with measurements. Many videos compare two transformers back to back or confuse average with peak power. It only becomes meaningful with a real load, with forward and reflected measurement, and with an eye on whether the core is warming up.

https://www.youtube.com/watch?v=tfiFPssSG4M

Video tip: typical mistakes with chokes, ununs and baluns in data mode operation, which is exactly where duty cycle turns into a problem.

Measure it, do not believe it

The performance of a common mode choke shows up clearly on a NanoVNA. You measure the impedance between the two shield ends, which is precisely the path common mode current would take. The result is often sobering: plenty of commercial chokes fall well short of their datasheet on individual bands.

https://www.youtube.com/watch?v=IrVBaAxBNdo

Video tip (German): the measurement setup and how to read the result for a common mode choke on the NanoVNA, step by step.

Three stubborn myths

A balun improves SWR. No. A 1:1 balun transforms nothing. If the reading changes after fitting one, that is because the feedline was radiating before and corrupting the measurement. The antenna is not better matched afterwards, it is merely measured honestly.
A balun replaces the tuner. No. A transformer shifts impedance by a fixed ratio. Whatever is still off after that remains the tuner's job.
Ferrite always helps. No. The wrong mix in the wrong place does little except get warm. And heat in the core is power that never reaches the antenna.

https://www.youtube.com/watch?v=W6xbXtsO1So

Video tip: the question it all comes down to, namely whether your particular antenna needs a balun at all.

What goes where

Dipole, inverted V, doublet fed with coax: 1:1 current balun at the feedpoint.
EFHW: 49:1 transformer plus a separate common mode choke about a tenth of a wavelength away, and a short counterpoise.
Random wire: 9:1 unun, counterpoise not optional, choke behind it.
Ladder line: a genuinely balanced tuner or a 4:1 current balun at the tuner output, never a voltage balun into the unknown.
Vertical with radials: needs no balancing, but almost always a choke, otherwise the cable becomes part of the counterpoise.
Magnetic loop: see the separate article, where the coupling loop does the matching.

Buy or build

Building your own is worth it because material and effort are modest: a core, some wire or coax, a weatherproof box. The real gain is knowing what is inside instead of trusting a label.

Commercial units make sense for high power or when the enclosure has to survive outdoors for years. Then two specifications are worth looking for, and both are often missing: the topology, current or voltage, and a power rating broken down by mode. A single number without a duty cycle says very little.

If you are planning the feedline as well, the cable types are covered in choosing coaxial cable and the matching losses in the attenuation calculator. What all of it does to the pattern can be explored in Antenna View.

Sources

Guanella and Ruthroff topologies and their behaviour under unbalanced loads, as covered in the literature on broadband transformers
Efficiency measurements of 49:1 and 64:1 transformers on mix 43, among others from the EFHW community
Ferrite manufacturer datasheets for mixes 31, 43, 52 and 61
hamwaves.com: Common Mode Chokes, a detailed treatment of choking impedance and construction
N1FD: Power Losses and Dissipation in Various Ferrite Devices, losses and heating in practice

73 – your oeradio.at editorial team

Transparency Notice

This article was researched and written with the support of AI (Claude, Anthropic) based on publicly available sources, and the content has been editorially reviewed. It was substantially expanded in September 2026, in particular with the distinction between current and voltage baluns, the choice of ferrite mix, the question of how much choking impedance is needed and the loss analysis of the 49:1 transformer. The previous AI-generated lead image was replaced by a real photograph. All images come from Wikimedia Commons under free licences, with photographer and licence given in each caption. The embedded videos come from external YouTube channels and reflect their views. Figures for losses and choking impedance are orders of magnitude from published measurements and do not replace measuring your own build. Corrections welcome at kontakt@oeradio.at.

Der Beitrag Understanding Baluns and Ununs: Proper Impedance Matching erschien zuerst auf OERadio.