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.

Meshtastic in Practice: Off-Grid Messaging with LoRa Mesh

Michael | OE8YML — Thu, 03 Sep 2026 07:00:00 GMT

Sending text messages, sharing GPS positions and receiving sensor data, without the internet, without a mobile network, without mains power. And all of it with hardware costing around 35 euros. What sounded like a niche project a few years ago is now a worldwide movement: Meshtastic, the open-source project for LoRa-based mesh communication.

This article gets hands-on. It covers which hardware makes sense, how setup works, what roles a node can take in the network, what the rules actually say and how things look in Austria. If you want to settle the system question first, the comparison is in MeshCom vs. Meshtastic, and for the wider picture see PMR vs. Meshtastic vs. CB radio.

What Meshtastic is

Meshtastic is open-source firmware that runs on cheap LoRa microcontrollers and turns them into a decentralised mesh. Every device receives messages and forwards other people's packets, so range grows with each additional node. There is no central server, no operator and no sign-up.

Kevin Hester started the project in early 2020. Hundreds of volunteers have carried it since, firmware ships at a brisk pace, and supported hardware ranges from 20-euro boards to professional gateways. How robust that has become was on display at Hamvention 2024, where 2,000 to 2,500 nodes were active on site at times, running the special Short Turbo preset for dense networks.

A Meshtastic message in the spectrum, here a 200-character transmission in the Medium Fast preset. The chirp pattern of LoRa modulation is clearly visible. Image: Tinux, CC0, via Wikimedia Commons.

The legal frame in Europe

This deserves a close look, because a lot of half-knowledge circulates. In Europe Meshtastic does not sit somewhere around 868 MHz, it sits in a clearly defined slice of it.

The EU_868 region occupies 869.40 to 869.65 MHz. Up to 500 mW ERP is permitted there, that is 27 dBm, with a 10 percent duty cycle. The default LongFast channel uses slot 1 with a centre frequency of 869.525 MHz. That is considerably more power than the frequently quoted 25 mW, which applies to other parts of the 863 to 870 MHz band.

What matters is this: legality comes from the combination of device, region setting, antenna and radiated power, not from the band alone. Put a high-gain antenna on a board already transmitting at full power and you can exceed the permitted ERP without noticing. And a radio amateur who moves to amateur frequencies is bound by amateur radio rules, including callsign identification and the ban on encryption.

Hardware worth considering

A word on prices first, since that is always the opening question. The figures below are September 2026 street prices at EU dealers who ship to Austria, VAT included. Ten euros between shops for the same board is normal, so comparing pays off. Three things come on top. A usable 868 MHz antenna costs 10 to 17 euros and is practically never included. When importing directly from the Far East, insist on the 868 MHz variant, because the widespread 915 MHz devices may not be operated here. And orders from outside the EU attract import VAT and, depending on value, customs charges, which often eats the saving.

Heltec LoRa 32 V3, around 23 to 30 euros

The budget entry. An ESP32-S3 with a small OLED and a LoRa chip, compact and well documented. GPS and a battery holder are missing and can be added. Perfectly fine as a fixed node or for a first try.

LILYGO T-Beam, from around 47 euros

The all-rounder with GPS, an 18650 holder and a LoRa module. At 24 to 48 hours of runtime it is the classic portable node for hiking. The GPS feeds automatic position reports into the mesh. The uprated T-Beam Supreme sits noticeably higher, usually between 60 and 75 euros.

LILYGO T-Echo, 60 to 80 euros

The frugal one. Built on the nRF52840, which draws far less than an ESP32. With an e-ink display, GPS and a battery it lasts a week under moderate use. Buying straight from the manufacturer is cheaper, at the cost of waiting for delivery.

RAK WisBlock, 27 to 47 euros

The modular system with an nRF52840 that takes GPS, sensors and a solar charge controller as plug-on modules. Deep sleep draws under 10 microamps, which is why it is the first choice for solar nodes. Price depends on the baseboard, with starter kits from about 27 euros and around 47 euros for the larger base. Anyone coming from the Raspberry Pi world knows the building-block idea.

RAK now also sells finished devices for anyone who would rather not solder: the WisMesh Tag at about 48 euros, the WisMesh Pocket V2 at 99 euros and the Repeater Mini V2 from roughly 100 euros.

Seeed SenseCAP T1000-E, around 48 euros

A tracker the size of a credit card. A finished device rather than a bare board, with GPS, buzzer and battery, thin enough for a pocket. For anyone who simply wants a working thing and no enclosure project, this is the easiest way in.

The SenseCAP T1000-E is a ready-made Meshtastic tracker in credit card size, GPS and battery included. Photo: XoMEoX, CC BY 4.0, via Wikimedia Commons.

LILYGO T-Deck, from around 70 euros

The standalone unit with a QWERTY keyboard, colour display and GPS. Messages can be typed on the device itself, no phone required. Handy when you do not want to pull out your phone every few minutes. The Plus variant with battery and GPS usually runs 85 to 120 euros in Europe.

Station G2

The heavy hitter with a 5-watt output stage, Ethernet and a proper enclosure. That power level is not permitted on the ISM band, so the device belongs on amateur frequencies and in licensed hands. As a hilltop site or fixed gateway it is a different league. We could not find a reliable Austrian list price, sales run through Unit Engineering with EU shipping and VAT handled by a German logistics partner. If you order, insist on the 868 MHz version.

Setup in fifteen minutes

Flash the firmware. Open flasher.meshtastic.org in Chrome or Edge, pick the board, connect via USB, flash. No download needed, the web flasher does everything.
Install the app. Meshtastic for Android or iOS, or the web client at client.meshtastic.org.
Pair. Power up the board, search in the app, connect via Bluetooth. The default code is 123456.
Set the region. Set the region to EU_868 in the settings. Skip this and the device either stays silent or transmits on the wrong frequency.
Choose a name. A short node name, twelve characters maximum. Radio amateurs usually use their callsign.
Send. Type a message on the primary channel. Every node in range receives it and passes it on.

The default preset is LONG_FAST, a sound compromise between range and speed. The one hard rule: every node in a mesh must run the same preset, otherwise they simply do not hear each other.

https://www.youtube.com/watch?v=a3FuIrGusnQ

Video tip (German): the Funkwelle channel starts its tutorial series with the fundamentals of LoRa and the Meshtastic network before touching any hardware.

Channels and encryption

Meshtastic supports up to eight parallel channels per device. Each channel has a name and a pre-shared key, and encryption uses AES in CTR mode.

The part many people miss: the key for the default channel is publicly known. Anyone who installs Meshtastic can read along there. That is deliberate, LongFast is the open community frequency. Anything that should stay private needs its own channel with its own key.

Since firmware 2.5 direct messages additionally use public key cryptography. Devices exchange their public keys themselves, the message is end to end encrypted, and nobody has to hand a shared key around. The 2.7 line added packet signing based on XEdDSA, which lets a receiver check where a packet actually came from.

For radio amateurs the logic inverts: encryption is not allowed on amateur frequencies. That is what the licensed operator mode is for, disabling encryption and sending the callsign.

Range, honestly

Urban: 0.5 to 2 kilometres with the stock antenna, buildings attenuate heavily at 868 MHz.
Rural: 5 to 20 kilometres depending on terrain and height.
Mountain to mountain with line of sight: 50 kilometres and beyond, where LoRa really shows its strength.
Record: 331 kilometres, set on 5 May 2024 between Austria and Italy across the Adriatic, using RAK4631 nodes, collinear antennas and the VERY_LONG_SLOW preset.

The biggest lever is not firmware but antenna and height. At 868 MHz propagation is almost optical. The same node might manage 500 metres on the ground floor and ten times that from a roof.

Roles in the network

CLIENT: the default. Sends, receives and forwards. Correct for almost everyone.
CLIENT_MUTE: sends and receives its own traffic but forwards nothing. Useful in very dense networks.
ROUTER: optimised for forwarding, display and Bluetooth off. Meant for permanent, usually solar powered sites in exposed positions.
ROUTER_LATE: like ROUTER but waits briefly. If a closer node has already relayed the packet, this one stays quiet, which avoids duplicates.
REPEATER: forwards everything, including packets already heard. Only sensible at genuine bottlenecks.

The community is unusually united here: as few routers as possible at strategically good points, everything else as a client. Too many routers create packet storms that clog the network instead of growing it. Since version 2.6 the NextHopRouter helps as well. For direct messages the firmware learns from the acknowledgements which node actually relayed the packet, and next time it addresses that one path instead of flooding the whole network.

https://www.youtube.com/watch?v=Af9MDVQ0M0o

Video tip (German): firmware installation, first setup and an initial field test, step by step.

MQTT: when the mesh reaches the internet

A node with Wi-Fi can bridge between the mesh and the internet and hand messages to an MQTT broker. That connects islands that are far apart.

A few things are worth knowing about the public broker at mqtt.meshtastic.org. The connection always uses TLS on port 8883, whatever the toggle in the app suggests. The default channel there carries heavy traffic, which can overwhelm weaker devices. Position data is deliberately blurred to protect privacy. And because the default channel key is known, anything going out that way is effectively readable by everyone.

If you want this done cleanly, run your own broker. How that works and how to connect to ours is described in OERadio goes Mesh. The result can be followed live on our Meshmap, which shows the known nodes in Austria and Europe. A broker on a Raspberry Pi is also the foundation for everything else, such as a bridge into HAMNET.

More than text

GPS and positions

Every node with GPS reports its position, and the app shows all nodes on a map. On a group trip everyone can see where the others are at a glance. Via MQTT and suitable software those positions can also be fed into the APRS network.

Sensors

The firmware knows more than 30 sensors. The common ones in practice: BME280 and BME680 for temperature, humidity and pressure, INA219 or INA260 for current and voltage, which solves half the troubleshooting on a solar node, plus pressure sensors for weather and even Geiger counter modules. Readings flow into the mesh automatically and can be evaluated over MQTT, which turns the network into a distributed measurement system.

Telemetry

Every node reports battery state, signal quality as SNR and RSSI, uptime and airtime usage. Airtime is the figure to watch, because it shows how close the network runs to the duty cycle limit.

Solar nodes, the backbone

The networks that stay interesting are the ones where somebody puts a node somewhere high and runs it self-sufficiently. That works because nRF52840 boards are extremely frugal.

A typical outdoor node from the inside: board, holder for two 18650 cells, charge controller, all in a weatherproof junction box. It does not take much more. Photo: -stk, CC BY-SA 4.0, via Wikimedia Commons.

Consumption: a RAK WisBlock with nRF52840 draws about 8 mA while receiving and under 10 microamps in deep sleep.
Panel: a small 1-watt 6-volt panel is enough for continuous operation.
Battery: one 18650 cell at 3,000 mAh covers several dull days.
Charging: the RAK baseboard already includes a solar charge controller.
Enclosure: an IP67 box from the electrical trade, antenna outside, glands on every cable entry.

For blackout preparedness such nodes are particularly valuable, because they keep running when power and mobile networks are gone. Anyone building this out systematically will find the complements in the emergency go-box and in Winlink for longer messages.

What licensed amateurs can add

Licensed operator mode: store the callsign, encryption off, operation under amateur radio rules.
More power: amateur frequencies allow entirely different levels than the ISM band, which is what devices like the Station G2 are built for.
Bridges: MQTT can feed positions into APRS or run gateways inside HAMNET, without any commercial internet.
Combining networks: the narrowband mesh complements an AREDN network where its directional links do not reach.

The situation in Austria

Austria is notably active on LoRa mesh, but spread across several systems, which regularly confuses newcomers.

For Meshtastic itself, meshtastic.at collects build guides and projects, from weatherproof outdoor nodes to pagers with a reply function and remote maintenance over GSM. The focus is firmly on building things rather than on network statistics.

Alongside it sits MeshCom as the Austrian amateur radio variant, now at version 4.0, and more recently MeshCore, which currently draws the most new participants in Carinthia. How fast that can go is visible in the growth to 32 sites within two weeks, including an observed link over 126.9 kilometres with half a watt. For the people behind the boxes, see the CarinthiaMesh repeater portraits.

In practice many operators run both. The hardware is the same, only the firmware differs, and a second node costs less than dinner.

https://www.youtube.com/watch?v=3lfxxC-z5Zs

Video tip: a practical comparison of common LoRa mesh devices, useful before a first purchase.

Practical tips

Antenna first

The supplied stubs are desk accessories. Even a quarter-wave wire, roughly 8.2 centimetres for 868 MHz, with a decent ground plane changes range dramatically. Ready-made SMA antennas start around five euros. No firmware setting comes close.

Height beats power

One more metre of height is usually worth more than another decibel. Given the choice, go to the roof, not the balcony.

Build for weather

Outdoor nodes need an IP67 enclosure and the antenna belongs outside it. Metal and condensation eat range. Seal cable entries with glands and add a desiccant pack.

Configure frugally

Position reports every 15 to 30 minutes, telemetry every 30 to 60, power saving on. A T-Echo then lasts a week on a small battery, and a RAK solar node runs as long as the cell holds up.

Pick the preset deliberately

LONG_FAST fits nearly every case. An isolated mountain node with few messages benefits from LONG_SLOW, dense urban networks from MEDIUM_FAST. The whole mesh has to agree, though.

Conclusion

Meshtastic stopped being a tinkering project some time ago. Hardware is cheap, firmware is stable, routing got considerably smarter with 2.6, and the community carries the project reliably. Getting in costs about 35 to 45 euros with an antenna, plus a quarter of an hour.

The network does live on its participants, though. A single node in a valley is a nice toy, twenty nodes on well chosen sites are infrastructure. So if you are wondering whether it is worth it, look at the map rather than at your own device.

Sources

meshtastic.org, official documentation on regions, presets, roles, encryption and MQTT
github.com/meshtastic/firmware, releases and changes in the current 2.7 line
Meshtastic blog on version 2.6, introduction of next-hop routing
meshtastic.at, build guides and projects from the Austrian scene
Wikipedia: Meshtastic, project history and context

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 revised in September 2026: the EU_868 figures were corrected to 869.40 to 869.65 MHz with up to 500 mW ERP and a 10 percent duty cycle, instead of the 25 mW stated before. The date and preset of the 331-kilometre record were corrected as well, it was set on 5 May 2024 using VERY_LONG_SLOW. Next-hop routing, packet signing, the T1000-E and the current situation in Austria were added. Prices were checked in September 2026 at EU dealers shipping to Austria, VAT included, and vary noticeably between shops and promotions. The 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. Corrections welcome at kontakt@oeradio.at.

Der Beitrag Meshtastic in Practice: Off-Grid Messaging with LoRa Mesh erschien zuerst auf OERadio.

New POTA website: next.pota.app is in public beta

Michael | OE8YML — Tue, 01 Sep 2026 16:00:00 GMT

Parks on the Air is rebuilding its platform, and since 31 August 2026 you can watch it happen: next.pota.app is available as a public beta. It runs alongside the familiar site, uses the same production database and accepts the same login. If you only want to read spots, you do not need an account at all.

The rebuild is more than a fresh coat of paint. Day to day it changes small things, but exactly the right small things. And for everyone who did not grow up speaking English, it changes quite a lot.

First impression: the site speaks your language

The most noticeable difference shows up before you click anything. The interface follows your browser language automatically. In German, "Spots" and "Activations" become Spots and Aktivierungen, and the menu offers Karte, Parkliste, Top-Aktivierer, Top-Hunter and Offizielle Veranstaltungen. The filter row is translated too: band, mode, program, QRT, age. POTA states that around 27 languages and localisations are planned.

The spot list on next.pota.app, in German without any configuration. Filters for band, mode, program, QRT and age, plus a dedicated column for comments. Screenshot: oeradio.at

That sounds like a detail, but it is exactly the hurdle newcomers in Austria have been stumbling over. Anyone activating their first park while simultaneously fighting jargon and a foreign language gives up sooner. Our POTA guide for Austria does not become redundant, but the official site now meets you halfway.

What changes about spotting

The spot list is where POTA actually happens, for hunters and activators alike. This is where the changes are felt most:

Comments persist. Previously the next spot overwrote the activator's note. Anyone who left "QSY 40 m in 10 minutes" or "break until 14:00" was anonymous again two minutes later. Now the note stays with the spot, which is probably the single most practical improvement.
Multi-select filters. Bands and modes can be combined instead of the previous "all or exactly one" choice.
Column picker and views. The table can be trimmed to what you actually need, and the view control switches between table and map.
QRT and age filters. Stations that have signed off can be hidden, and the time window is adjustable, with 30 minutes as the default. A visible countdown shows the next refresh and can be paused when you want to read in peace.
Region at a glance. A dedicated column shows the region, such as AT-KA or DE-RP. Handy when you are looking for European activations instead of scrolling past US spots.

There is also a new Geographic Achievement page that tracks which regions you have worked or hunted from.

The park page: much more than coordinates

Open a reference and you now get a proper park page. Take AT-0016 Dobratsch Nature Reserve, the view shown in this article's lead image: reference, entity, federal state (Carinthia, AT-KA), coordinates including the locator JN66uo, activity status and a map that places the reserve at a glance.

The numbers below are more interesting. The Dobratsch was first activated on 6 October 2014 by PA3FYG and has since reached 24 activations from 27 attempts and 663 QSOs. Underneath sits a leaderboard for the park with familiar callsigns: OE8YML with 15 activations and 456 QSOs, followed by OE8YAK and DL7PIA. A list of recent activations runs alongside, broken down into CW, data and phone.

Two fields are new and rather clever: early shift and night shift success times. For AT-0016 they read 1:00 to 7:00 UTC and 17:00 to 1:00 UTC. That is not an oracle but an evaluation of when activations at this park have actually worked in the past. If you are planning a trip and wondering whether the early start is worth it, you finally have a number instead of a hunch.

The map

The map view has been rebuilt, with Mapbox underneath and switchable between standard, outdoor, satellite, streets and dark. A "parks in view" list runs alongside it and updates as you pan. Distances can be switched between kilometres and miles, and for once that is not a US-only default.

Map view over the Alps. There are 1,877 parks in this frame, and zooming in resolves the clusters into individual references. Screenshot: oeradio.at

For trip planning this is the most interesting corner of the site. Two-fers and multi-references are far easier to find on a map than in a list. What that looks like in practice we described at the Pyramidenkogel, where SOTA, POTA and TOTA came together in a single activation.

Why rebuild at all?

The answer is unglamorous and familiar to many long-running amateur radio projects. The existing platform dates back to 2018 in its essentials, grew on a classic LAMP stack, and by now only a handful of volunteers know it well enough to work on it safely. Meanwhile POTA has exploded: from roughly 1,200 participants in the early days to somewhere between 85,000 and over 90,000 users today, depending on which source you take, with 100,000 seen as this year's milestone. Infrastructure costs run to several thousand dollars a month according to those running it.

The rebuild therefore uses the PHP framework Laravel and a redesigned cloud setup that scales with traffic peaks. The stated goal is explicitly not just "prettier" but maintainable by volunteers who do not need enterprise experience. The roadmap includes public APIs, faster log processing, expanded award handling, club statistics, better accessibility and integrated documentation.

The work is carried by a small volunteer team around Thom Martin, W8TAM, and Mike Case, W8MSC, with contributions from Mark Torigian K8MST, Jeremy Turner N0AW, Colby Dillion WR5B and James Linden VE3JLN. Notably, and openly communicated, the team also uses AI tooling to get anywhere at all with such a lean crew, with experienced developers reviewing the code. You can see how fast they iterate at the bottom of the site. There is a build timestamp there, and when you look it is typically from the same day.

https://www.youtube.com/watch?v=_t7OG8XLqJI

Video tip: the AlpineRadioWaves channel walks through the new site, from the spot view via the filters to the map, and shows what still trips up in beta.

What it means for Austria

At the time of this research the POTA database lists 423 references with an AT prefix. Of those, 390 have been activated at least once, together well over 151,000 QSOs. The country is effectively covered. The days of easy first activations are largely gone, but there is almost always something within reach.

The most-activated Austrian parks:

AT-0250, Hohe Wand, Schneeberg and Rax (Natura 2000): 171 activations, over 11,600 QSOs
AT-0282, European long-distance trail E4: 154 activations, activatable across eight federal states
AT-0217, Enzesfeld-Lindabrunn-Hernstein protected landscape: 153 activations
AT-0301, Wiener Alpenbogen trail: 146 activations
AT-0265, Pecherlehrpfad Hernstein: 145 activations
AT-0176, Wienerwald Biosphere Reserve: 143 activations

What stands out is how firmly Lower Austria holds the top of the list. The area around Vienna is densely covered with references and quick to reach. In Carinthia, where we operate ourselves, the numbers are smaller but the parks are often more spectacular. See for example our activations in the Schütt and on the Dobratsch. If you are looking to start, the OE POTA team is the place to ask.

What it is all about in the end: an hour of time, a folding table, an antenna. The website is only the tooling around it. Photo: Evesiesta, CC BY-SA 4.0, via Wikimedia Commons.

Beta means beta

A few things belong in an honest account:

It is a test version on live data. The site is attached to the production database, so what you spot there is real. Display glitches are possible, and the interface keeps changing.
Filters only cover what exists. The band selector currently only offers bands where somebody is active right now. If you want to keep 10 m permanently in view so you can pounce the moment something appears, you cannot preselect that yet. Community test reports raise the same point.
The old world keeps running. pota.app and the existing API are unchanged. Third-party tools and logging apps still pull their data from there, so there is no need to rush a switch.

https://www.youtube.com/watch?v=KWK2FJ4h8co

Background: the Hamvention talk "Parks on the Air 2.0" explains why the rebuild became necessary and how the platform is meant to cope with growth.

What you can do now

Take a look, risk-free. Open next.pota.app in a browser, the spot list is visible without a login.
Test it with your own account. Same login as before. If you are spotting anyway, you might as well spot there.
Give feedback. That is what a beta is for. Whatever does not fit in Austria, whether translations, region codes or park names, nobody else is going to notice.
Check the park data. If you know of an error in an AT reference, such as wrong coordinates or an outdated name, report it. POTA describes the mapping teams as one of the bottlenecks in its growth.

Sources

next.pota.app, the beta itself, observations as of 1 September 2026
pota.app and docs.pota.app, existing platform and rules
AE5X: POTA website gets a facelift, first hands-on report
UFRC: Next.POTA.app est en ligne, context including languages and costs
Q5: The Volunteers Rebuilding Ham Radio's Fastest-Growing Movement, background on architecture and team

Related on our site: POTA in Austria, the beginner's guide, how POTA fever caught us, the best portable antenna for SOTA and POTA and WWFF in Austria as a related programme.

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. The description of the interface is based on our own inspection of next.pota.app on 1 September 2026. A beta changes, so deviations are to be expected. The figures on Austrian parks come from our own analysis of the public POTA program data as of 1 September 2026. User numbers, costs and architecture come from the articles linked under "Sources", which differ in detail, which is why we give ranges. The screenshots are ours and show a third-party website, and the station photo carries photographer and licence in its caption. The embedded videos come from external YouTube channels and reflect their views. Corrections welcome at kontakt@oeradio.at.

Der Beitrag New POTA website: next.pota.app is in public beta erschien zuerst auf OERadio.

Yaesu C4FM/Fusion: Analog-Compatible Digital Voice

Michael | OE8YML — Mon, 31 Aug 2026 07:00:00 GMT

C4FM is Yaesu's digital voice mode, marketed as System Fusion. Its unique selling point is right there in the name: because C4FM is a flavour of frequency shift keying, it sits technically close enough to plain old FM that both worlds can share the same repeater. A radio works out by itself what is on the channel and adapts. This article explains what is actually being transmitted, how linking works via WIRES-X, YSF and the Austrian YCS232 — and where the limits of the system are.

If you are after the practical first steps rather than the technology, our compact guide is C4FM / Yaesu Fusion in Austria: Getting Started. And if you are still deciding which digital system to pick at all, compare them in D-STAR vs. DMR vs. C4FM vs. M17.

Where System Fusion comes from

When Yaesu introduced System Fusion in 2013, the digital voice train had long left the station: D-STAR had been running since the early 2000s, and DMR had spilled over from commercial radio into amateur use. Yaesu's answer to being late was less technical than strategic: analog compatibility plus an aggressive repeater programme that let clubs buy Fusion repeaters at a steep discount.

The calculation worked. A repeater that serves both worlds does not split a club — the analog regular net carries on, and whoever wants digital can have it. Neither D-STAR nor DMR offers that, and it remains the strongest argument for Fusion to this day.

What happens on the air: 4FSK at 9600 bps

C4FM spelled out is Continuous 4-Level FM. Instead of two frequencies as in classic FSK there are four deviations from the carrier — and because four states encode exactly two bits, every symbol carries a bit pair (a dibit). At 4800 symbols per second that yields a gross data rate of 9600 bps in a 12.5 kHz channel raster.

Four frequency levels, each standing for a bit pair: that is how C4FM reaches 9600 bps at 4800 symbols per second. Graphic: oeradio.at

Those 9600 bps are the cake that voice, error correction and data have to share — and the way you slice it produces the different operating modes. Speech coding is always handled by the AMBE+2 vocoder, the same codec family used by D-STAR (as AMBE) and DMR. It is proprietary and licensed — more on that below.

The four operating modes

System Fusion knows four modes, and depending on the settings the radio switches between them by itself:

DN — Digital Narrow (V/D mode): the default. Voice and data run simultaneously. Of the 9600 bps roughly 2450 bps go to the vocoder, about 1150 bps to voice error correction, and the rest to a data channel (callsign, GPS position, short messages) with its own protection. All that FEC is why DN reaches furthest — and why it has a slightly "digital" sound.
VW — Voice Wide (Voice FR): the full data rate goes into speech, roughly 4400 bps vocoder plus 2800 bps FEC. Audibly better, almost studio-like up close — but the link breaks down sooner on weak signals. No data channel.
DW — Data Wide (Data FR): maximum throughput for data instead of voice — in practice for images and file transfer between radios.
Analog FM: ordinary narrowband FM, exactly as any other handheld does it.

What matters day to day: a radio in DN mode does not automatically decode a VW transmission at full quality, and vice versa. On repeaters and reflectors DN is therefore the de-facto standard — VW is reserved for simplex links and local nets where everyone involved knows what they are doing.

AMS: the actual trick

AMS stands for Automatic Mode Select, and it is the feature that earned Fusion its reputation. On every incoming transmission the radio evaluates whether it is analog FM or a C4FM data stream and switches the receive path within milliseconds. On transmit it can remember which mode the last station used and reply in kind.

For repeater operation that means: a Fusion repeater accepts both and passes both on — analog in, analog out; digital in, digital out. The analog local net notices nothing of the digital traffic apart from the occasional burst of noise when somebody comes through digitally. DMR and D-STAR repeaters cannot do this: there, the channel is either digital or it is not.

The price: a mixed repeater is only ever occupied by one flavour at a time. DMR can run two separate time slots on the same frequency via TDMA, C4FM cannot. If you need capacity, DMR serves you better; if you need to stay compatible with what is already there, Fusion does.

https://www.youtube.com/watch?v=hHLyI7B4NAI

Video tip: how Fusion, C4FM and WIRES-X relate to each other — sorting out the three terms that get mixed up most often in everyday use.

DG-ID and DP-ID: CTCSS for digital operation

Since the second generation (System Fusion II, from around 2017) every transmission carries two extra identifiers:

DG-ID (Digital Group ID): a number from 0 to 99. It acts like a CTCSS tone, only digital: the radio only opens when the received DG-ID matches the one set. DG-ID 0 is the "let everything through" state. Transmit and receive DG-IDs can be set separately — the equivalent of split CTCSS.
DP-ID (Digital Personal ID): a radio-bound identifier for the GM (Group Monitor) function, which lets small groups see each other on the display — including distance and bearing when GPS is active.

The DG-ID is more than a squelch: on linked repeaters and YCS servers it is the way you select the talk group — functionally what the talkgroup is in DMR and the reflector module in D-STAR, only without registration and without a codeplug.

Linking: WIRES-X, YSF and YCS

Beyond RF, Fusion is linked in three different ways — and these are the most common stumbling block for newcomers, because they sound alike but are separate systems.

WIRES-X — Yaesu's own network

WIRES-X (Wide-coverage Internet Repeater Enhancement System) is the manufacturer's own linking system. Stations meet in rooms, each with a numeric ID; a node is the access point bridging RF and internet. It is operated straight from the radio — via the red X key used to search nodes and connect rooms.

The classic way to run a node is the HRI-200 interface plus a PC. It also works without extra hardware: in PDN mode (Portable Digital Node) a suitable radio — FT5D, FT3D, FT2D, FTM-400XD, FTM-300D, FTM-200D or FTM-100D — hangs off a Windows PC via USB and becomes the access point itself. No static public IP required. Node and room IDs are issued by Yaesu; without that registration nothing happens on the WIRES-X network.

YSF reflectors — the open counterpart

Alongside it there is the YSF world, grown around the free MMDVM software by Jonathan Naylor, G4KLX. A YSF reflector is a virtual room that hotspots and homebrew repeaters dial into. There is no central registry: whoever wants to run a reflector, runs one. That is exactly what makes the scene lively — and confusing. Older FCS reflectors are the predecessor concept and have effectively been superseded in Austria since 2018.

Important: a Yaesu repeater in WIRES-X mode cannot reach a YSF reflector directly — that needs a bridge in between. Hotspots, on the other hand, speak both protocols without trouble.

YCS — System Fusion II as a server

The YCS server is the evolution of the YSF reflector: instead of a single room it manages many groups in parallel, addressed by DG-ID. A repeater is therefore no longer stuck in one room but passes all groups through; which one you hear is decided by the DG-ID in your own radio. On top of that a YCS records the callsign and position data from the data channel and shows them on a dashboard.

Two routes into the network: through a Fusion repeater into the WIRES-X rooms, or through a repeater or hotspot into the open YSF/YCS world. Connecting the two needs a bridge. Graphic: oeradio.at

C4FM in Austria: YCS232 and the DG-ID groups

The Austrian Fusion network today largely runs on the YCS232 — the national System Fusion II server, operated in the ÖVSV orbit. Group selection happens via DG-ID:

DG-ID 32 — AT-C4FM-Austria, the nationwide group. If you set only one, set this one.
DG-ID 91 — OE1 / eastern region, 93 — Lower Austria, 98 — OE8 Carinthia: the regional groups.
DG-ID 28 — Switzerland, 62 — Germany: the neighbours on the same server.
DG-ID 99 — echo, the self-test: you hear your own transmission played back and know instantly whether modulation and path are fine.

Every connected repeater also has a fixed DG-ID assigned so that allocations do not clash. For the Yaesu-native world there is the WIRES-X room "OE AUSTRIA ALL". And because the multi-protocol reflector XLX905 also accepts C4FM, you end up in the same net as D-STAR and DMR stations there.

The Austrian C4FM repeater list currently holds around 26 repeaters. Most are on 70 cm with −7.6 MHz offset, a few on 2 m with 600 kHz. A cross-section:

OE1XAT Vienna/Wienerwald — 438.3625 MHz, YCS System Fusion II
OE2XZR Gaisberg — 438.550 MHz, YCS
OE5XOL Linz/Breitenstein — 438.2875 MHz, YCS
OE5XGL Grünberg — 145.750 MHz (2 m), YCS
OE6XAG Schöckl — 437.975 MHz, YCS
OE7XCJ Innsbruck — 438.400 MHz, YCS
OE8XKK Pyramidenkogel — 439.075 MHz, YCS
OE7XLI Lienz/Hochstein — 439.075 MHz, one of the few running WIRES-X

A handful deliberately run without linking — OE3XDA on the Hochkogelberg, OE5XKL on the Krippenstein or OE6XPG on the Planai. The current list with offsets and DG-IDs is maintained on the C4FM Austria site; which group is active right now is shown live by the YCS232 dashboard. For the wider picture of what else is on the air, see our overview of VHF/UHF repeaters in Austria and the map in Relaisblick.

https://www.youtube.com/watch?v=KrXxeuUee2M

Video tip (German): Austria's move to YCS / System Fusion II — why DG-ID groups replaced the single reflector and what that means at the radio.

Radios: Yaesu and nobody else

C4FM is a Yaesu standard, and unlike DMR there is no third party building cheap radios for it. If you want Fusion, you buy Yaesu. The usual suspects:

FT-70DE — the entry-level handheld: 5 W, C4FM and FM, no GPS, no colour display. The cheapest way into the mode.
FT3DE / FT5DE — the full package: colour touchscreen, GPS, Bluetooth, APRS, PDN-capable. The FT5DE is the current step.
FTM-200DE / FTM-300DE — 50 W mobiles with GPS and AMS; the FTM-300DE with the larger feature set.
FTM-500DE (and the newer FTM-510DE line) — true dual receive, two active receivers at once, AESS speaker concept.
FT-991A — the all-rounder: HF, 6 m, 2 m and 70 cm in all modes, C4FM on VHF/UHF included.
DR-2X / DR-2XE — the repeater itself, with AMS operation and an optional LAN unit.

The FT-991A brings C4FM along as a side effect: buy the station for HF and you are digitally QRV on 2 m and 70 cm as well. Photo: mick m43, CC0, via Wikimedia Commons.

On the repeater side Yaesu adds IMRS (Internet-linked Multi-site Repeater System): with the optional LAN unit up to 99 DR-2X repeaters can be linked over IP — a manufacturer-native repeater chain, independent of WIRES-X. It plays almost no role in Austria, because linking runs through the YCS232.

No repeater in range: the hotspot

If no Fusion repeater is reachable, a hotspot gets you into the network: an MMDVM board on a Raspberry Pi running Pi-Star or the more modern WPSD. The hotspot dials into a YSF reflector or straight into the YCS232, and group selection remains the DG-ID on the radio. Step by step instructions are in Setting up a Pi-Star hotspot. As always: valid licence, frequency per band plan, minimum power.

What else C4FM can do: GPS, messages, images

The data channel in DN mode is not just there for the callsign. It carries the GPS position — on a YCS the positions land in the dashboard, and via suitable gateways they also reach the APRS network. Add short text messages between radios and, in DW mode, even photos from the optional camera speaker-microphone. Day to day that is a gimmick; for training, field days and contest logistics it is occasionally useful.

The GM (Group Monitor) function shows which stations of your own group are currently in range — with distance and bearing. On a field day with several teams that may be the single most underrated feature of the whole system.

Where the limits are

Three points belong in an honest account:

One manufacturer, one ecosystem. There is no alternative to Yaesu hardware, and therefore no price pressure. DMR handhelds start just over a hundred euros; an FT5DE costs four to five times that.
Proprietary codec. AMBE+2 is licensed intellectual property owned by DVSI. Fusion cannot be fully reimplemented in free software — precisely the point where M17 steps in with the open Codec2.
WIRES-X is closed. Node and room IDs come from Yaesu, and the software is Windows-only. The YSF/YCS world is the open answer — but it is a parallel world, not an extension.

Against that stands the one advantage no other system has: no registration, no codeplug, no talkgroup studies. Enter callsign, set DG-ID, press PTT. That is why Fusion is many people's first digital mode — and for some the only one they need.

QRV in three steps

Enter your callsign. Once, in the setup menu. No online registration, no ID to apply for.
Pick a target. An Austrian Fusion repeater from the list, the WIRES-X room "OE AUSTRIA ALL", or — via hotspot — the YCS232. Frequencies and offsets are conveniently loaded into the radio by the Memory Channels Processor.
Set the DG-ID and listen. 32 for Austria, plus your regional group. A quick test on DG-ID 99 (echo) answers the question "am I getting in at all?" in five seconds. Then call with your full callsign.

Further sources

ÖVSV Wiki — C4FM category
ham-c4fm.at — repeater list, DG-ID groups and guides for Austria
YCS232 dashboard — live view of active groups and repeaters
systemfusion.yaesu.com — manufacturer documentation on modes, WIRES-X and the DR-2X

Related on our site: Getting started with C4FM in Austria, D-STAR explained, DMR for beginners and EchoLink, AllStarLink and SvxLink for the analog counter-proposal.

This page is part of our digital voice overview — compare all modes there.

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; the content has been editorially reviewed. In September 2026 the piece was substantially reworked and extended with the technical fundamentals, the network architecture and the Austrian DG-ID groups. Figures on modulation, data rates and operating modes come from Yaesu documentation and publicly available technical write-ups; repeater and DG-ID details come from ham-c4fm.at and the ÖVSV Wiki — repeater data changes, so the lists there take precedence. Lead image (Yaesu FT3D) by Ohhai-emre, CC BY-SA 4.0, via Wikimedia Commons, cropped; the equipment photo carries photographer and licence in its caption; the diagrams are ours. The embedded videos come from external YouTube channels and reflect their views. Corrections welcome at kontakt@oeradio.at.

Der Beitrag Yaesu C4FM/Fusion: Analog-Compatible Digital Voice erschien zuerst auf OERadio.

Icom IC-7110: the X-026 concept becomes a production radio

Michael | OE8YML — Sat, 29 Aug 2026 17:50:00 GMT

Since April the scene has been guessing about a radio of which only the case was ever shown. On 29 August, at the Tokyo Ham Fair, Icom gave the answer: the X-026 concept goes into production as the IC-7110, the successor to the IC-7100.

We took a sober look at the mock-up back in April in Icom X-026: new concept radio to be unveiled at Hamvention and wrote at the time that nothing beyond the case was known. Now there is a spec sheet. Here is what is actually confirmed — and what is still missing.

What the IC-7110 is

An all-mode mobile radio with a detachable control head, so the same idea as the IC-7100 of 2013: one radio for the car and the shack, covering everything from HF to UHF.

Bands: HF / 50 / 70* / 144 / 430 MHz (*70 MHz on the European version only)
Receive: continuous from 30 kHz through the 144 MHz band, including FM broadcast and airband
Modes: SSB, CW, RTTY, AM, FM and D-STAR DV
Power: 100 W on HF and 50 MHz, 50 W on 144 and 430 MHz
Variants: IC-7110 at 100 W, IC-7110M at 50 W, IC-7110S at 20 W
Display: 4.3-inch colour with touch operation
Two independent receiver chains for HF+50 MHz and for VHF/UHF, on two separate antenna connectors
Dualwatch for HF/VHF and HF/UHF, including simultaneous DV reception
Real-time spectrum scope with waterfall, audio scope, CW decoder
Wi-Fi (2.4 and 5 GHz), Bluetooth 5.3, GNSS receiver
Control head with tripod thread (1/4-20), speaker, microphone jack and SD slot in the head
Front-mounted cooling fan
No internal antenna tuner

The two points people will argue about

First, the two receiver chains. That is the real difference from the IC-7100, which could only serve one receiver; if you were on HF and wanted to monitor the local repeater on the side, tough luck. The IC-7110 now has two chains and two connectors. For mobile operation that is the most practically relevant gain, because you can drive along and still be reachable on 2 m.

Second, the missing tuner. The IC-7100 did not have one either, so this is no step backwards — but it does mean a matching unit has to be budgeted alongside the radio unless you work exclusively with resonant antennas. Icom showed the AH-6 tuner at Hamvention in May, which fits exactly this gap. Anyone doing the sums should plan the tuner in from the start. What a tuner does and does not do is covered in Antenna tuners: manual or automatic.

The 70 MHz on the spec sheet — and what applies in Austria

Every European announcement lists the 4 m band as standard. In the UK that is a selling point. In Austria it is a footnote with a trip to the authorities.

The 70 MHz band is not regularly allocated here. The ÖVSV applied to the telecoms authority in June 2024 for an allocation of 70.0 to 70.5 MHz; to this day it does not appear in the band plan. What does exist are exception permits: individual authorisations from the telecoms authority in coordination with the ÖVSV, intended as a trial run for possible future inclusion in the Frequency Utilisation Ordinance.

The key figures of those permits: 70.0 to 70.5 MHz, a maximum of 25 watts, with narrow-band digital modes such as FT8, FT4, Q65, MSK144 and FSK441 permitted, plus A1A, F3E and J3E. In practice, applications have also been granted for sub-ranges such as 70.150 to 70.175 MHz, with an annual fee of around 241 euros and a process that requires patience.

For a purchase decision that means: in Austria the 70 MHz in the IC-7110 is not a band you simply switch on, but one you need a permit for first. The wider framework is in our article on the Frequency Utilisation Ordinance. The same amendment that capped 23 cm at 10 watts did nothing at all for 4 m.

What is not known yet

And now the part you have to go looking for in the announcements: Icom has given neither a price nor a delivery date. No production schedule, no availability, no RRP. British dealers have already put up product pages, but without prices.

Equally open are the things that can only be judged with the radio in front of you: how good the receiver design is in a crowded band, how loud the front fan gets in the shack, how fast the waterfall really runs, and how the interface feels in a car. Icom describes it as following the IC-705 — anyone who knows that radio has a rough idea what to expect. We have a separate article on the IC-705 covering remote operation with Tailscale.

Putting it in perspective

The IC-7100 was on the market for thirteen years and is still the radio you recommend to someone with a car, a small shack and no second budget. A successor was overdue, and what is on the spec sheet looks like a clean generational change: touchscreen instead of key menus, a waterfall instead of columns of numbers, two receivers instead of one, wireless links to the computer instead of a cable tangle.

Whether that is worth the premium can only be said once Icom names one. Until then: the radio exists, it is no longer a mock-up, and the successor to the best-selling all-band mobile of the past decade has a name.

If you get your hands on one — at a show, at a dealer, anywhere: write to us. A first impression from a real operator is worth more than ten spec sheets.

73 – your oeradio.at editorial team

Transparency Notice

This article was researched and written with the support of AI (Claude, Anthropic). Sources are the announcements by Icom Europe and Icom UK on the presentation at the JARL Ham Fair on 29 and 30 August 2026, the published pre-release data on the IC-7110, and for the 4 m section the ÖVSV wiki and the account of the exception permits at mpdx.at. All technical figures come from manufacturer documentation — we did not have a radio in hand and claim no measurements of our own. The lead image is an AI-generated illustration and does not show a real radio — no freely usable press photos of the IC-7110 are available from Icom yet. Editorial responsibility and content review rest with the oeradio.at editorial team. Corrections are welcome at kontakt@oeradio.at.

Der Beitrag Icom IC-7110: the X-026 concept becomes a production radio erschien zuerst auf OERadio.

Amplifiers: Selection, Safety and Grounding

Michael | OE8YML — Sat, 29 Aug 2026 07:00:00 GMT

An amplifier is the most expensive box in the shack that contributes the least to making contacts — and yet almost everyone wants one eventually. This article works through what an amplifier really buys you, what the law in Austria actually says, how tubes and LDMOS differ in practice, how to set up drive, ALC, cooling and grounding, and how to spot a decent used unit.

Classic operating philosophy: TUNE and LOAD on an OM Power tube amplifier, with a digital wattmeter above. Photo: Karl-Martin Skontorp, CC BY 2.0, via Wikimedia Commons.

What more power actually buys you

The most important number first, because it frames the whole discussion: power works logarithmically. On HF, one S-unit is defined as 6 dB — four times the power.

100 W → 400 W = 6 dB = exactly one S-unit
100 W → 1000 W = 10 dB = roughly 1.7 S-units
5 W (QRP) → 100 W = 13 dB = a bit over two S-units

Going from 100 to 1000 watts multiplies your power by ten and buys you just under two S-units. For comparison: swapping a vertical for a three-element Yagi gains about the same — in both directions, so on receive too, and without an electricity bill. Hence the old rule still holds: a euro spent on the antenna beats the same euro spent on the amplifier. If there is still headroom in your vertical, your EFHW or a directional antenna, start there.

That said, there are situations where an amplifier is the only answer:

Pile-ups in contests and on DXpeditions — what counts is not absolute field strength but the margin over everyone else calling
EME and meteor scatter — physically impossible without high power
Compromise antennas — a magnetic loop or stealth antenna costs dBs that power can partly replace
Low bands — 160 m and 80 m forgive very little, especially in summer

And there is one situation where an amplifier helps not at all: when you cannot hear the other station. Power does not improve your receiver. If you sit in a noise floor, the money is better spent on receive antennas and on hunting down the noise in your own house.

The legal framework: what is actually allowed in Austria

One misunderstanding is remarkably persistent: "a CEPT licence means 1 kW." It does not. What governs is the Frequenznutzungsverordnung 2013 (Federal Law Gazette BGBl. II No. 63/2014), Annex 4, as amended by the 2023 amendment BGBl. II No. 61/2023, in force since 13 March 2023.

The normal case: 400 watts

For holders of licence class 1, the regular ceiling on the HF bands is 400 W PEP. That is the power almost every Austrian station legally runs — and a 600-watt amplifier covers it with room to spare.

For licence classes 3 and 4, the limit is 100 W. More importantly in practice: in those classes, Annex 4 permits only unmodified commercial transmitting equipment. An external amplifier — let alone a homebrew one — is therefore effectively out of the question for class 3 and 4. Anyone wanting to move up takes the class 1 exam first; our licence class comparison lays out what each class is good for.

High Power: 1 kW on application

Since the 2023 amendment, the "High Power" level of 1000 W PEP can be applied for. The conditions, according to the Fernmeldebüro (the Austrian telecoms authority):

licence class 1 only
only on the HF bands 80 m, 40 m, 20 m, 17 m, 15 m, 12 m and 10 m
the prerequisite is "at least one year of interference-free operation at power level B for the authorised location" — an existing power level C authorisation waives the waiting period
application via the RAT system; High Power operation is prohibited until approval is granted
the authorisation is tied to the location and carries a fee (on the order of 6.5 euros per month)

The "interference-free operation" clause is not a formality: if you have been in the neighbours' television for years, you will not get a power increase. That is a good reason to do the EMC homework before buying an amplifier rather than after.

The bands in detail

Band	Max. power, class 1	High Power possible?
160 m (1810–1850 kHz)	200 W	no
160 m (1850–2000 kHz)	100 W	no
80 m	400 W	yes
60 m (5351.5–5366.5 kHz)	15 W EIRP	no
40 m	400 W	yes
30 m	200 W	no (WARC)
20 / 17 / 15 / 12 / 10 m	400 W	yes
6 m (50–52 MHz)	200 W	no
6 m (52–54 MHz)	100 W	no
2 m and 70 cm	up to 1 kW — but only EME and meteor scatter with Yagis of at least 15 dBd	special case
23 cm	10 W (GNSS protection)	no
13 cm and above	200 W	no

On the WARC bands (30, 17, 12 m) the IARU agreement that no contests are run there applies as well — along with the good manners of not overdoing the power. For the heavily trimmed 23 cm band, see our microwave article.

Spurious emissions, dummy load, CE

Three provisions of the Austrian Amateurfunkverordnung (AFV) bear directly on amplifier operation:

§ 17 — unwanted emissions must be kept "to the lowest possible level"; between 50 and 1000 MHz a suppression of at least 60 dB relative to peak power applies. Without an effective harmonic filter behind the amplifier that is unachievable.
§ 14 — transmitter tuning requires tuning without unnecessary radiation — in practice: into a dummy load. For tube amplifiers with TUNE and LOAD that is not a recommendation but a legal requirement.
§ 13 — monitoring instruments requires suitable current and voltage meters. For an amplifier that means plate current, plate voltage, forward and reflected power must all be readable.

On CE marking: commercially bought amplifiers require CE marking under the Radio Equipment Directive RED 2014/53/EU and the EMC Directive. Homebrew equipment and kits built by and for radio amateurs are explicitly excluded under Art. 1(2)(c) RED as long as they are not made available on the market. Building your own is therefore permitted — which does not exempt you from the limits in § 17 AFV.

https://www.youtube.com/watch?v=rSdOjGi78CQ

Homebrew amateur radio: 1400 W and 600 W amplifiers by Jörg Müller (DJ8YP) — construction, cooling, filtering (source: YouTube, German)

Tube or LDMOS?

The argument feels as old as the hobby, but technically it is fairly settled by now — with a few exceptions.

The classic: a Collins 30L-1. Plate meter, LOADING, TUNING, band switch — that is the entire front panel, and every control wants attention at each band change. Photo: RadiomanPA, CC BY-SA 3.0, via Wikimedia Commons.

Tube amplifiers

Usually grounded-grid triodes (3-500Z, 3CX1500A7) or tetrodes (GU-74B, 4CX800). The output network is a tunable pi filter — hence TUNE and LOAD, hence the manual band change.

Forgiving of mismatch. A 3:1 SWR costs a tube some efficiency; it kills an LDMOS module.
The pi network attenuates harmonics by design — a structural advantage where § 17 is concerned.
Repairable. Change the tube, change a capacitor, carry on.
But: 2000 to 4000 volts on the plate, 20 to 40 kilograms, warm-up time — and tube supply has become a problem. Russian types such as the GU-74B have been hard to source through regular channels since 2022, and prices for new American classics have risen sharply.

LDMOS amplifiers

Today's standard. One or two power transistors — usually BLF188XR or MRF1K50 — running on 50 to 65 volts, broadband, with switched low-pass filters per band.

No tuning. Band changes in milliseconds, often automatically from the transceiver's band data. Practically mandatory for SO2R and serious contesting.
No high voltage in the dangerous sense — 50 V is unpleasant, not lethal.
Compact and light, some models under 15 kg, a few even portable.
But: extremely sensitive to mismatch and overdrive. Without working protection circuitry a module dies in milliseconds — and a BLF188XR is a three-figure part.

	Tube	LDMOS
Band change	manual (TUNE/LOAD)	automatic, instant
Operating voltage	2–4 kV	50–65 V
Efficiency	approx. 55–65 %	approx. 55–70 %
Behaviour at SWR > 2:1	forgiving	must shut down or it dies
Harmonic suppression	inherent via pi network	via switched low-pass filters
Weight	20–40 kg	10–20 kg
Readiness	1–3 min warm-up	instant
Repair	quite feasible	module replacement, expensive
Spares	tube sourcing difficult	readily available

https://www.youtube.com/watch?v=j3f2OaWbjyM

Ask Dave (KE0OG): tube versus solid state — the trade-off in under ten minutes (source: YouTube, English)

https://www.youtube.com/watch?v=4hCtv7HKBkY

A detailed hands-on review of a 1 kW LDMOS amplifier (Palstar LA-1K), measurements included (source: YouTube, English)

The specifications that matter

Drive power and gain. Typical figures are 12 to 14 dB of gain. A 1.3 kW LDMOS amplifier therefore needs roughly 40 to 60 watts of drive; a 1 kW tube amplifier needs about the same. If you run a QRP transceiver such as the IC-705 (10 W), you need either a high-gain amplifier or a two-stage arrangement — feeding 10 W into a kilowatt amplifier yields a third of rated output at best.

Intermodulation (IMD3). The decisive quality figure, and the only one the rest of the band notices. Good amateur amplifiers sit at −30 to −35 dBc for third-order products. Cheap unfiltered CB-style "burners" are orders of magnitude worse and produce a signal that splatters more than 20 kHz wide.

Duty cycle. The most consistently underestimated parameter:

Mode	Average power	On a 1 kW amplifier
SSB (voice)	approx. 20–25 %	full power is fine
CW	approx. 40–50 %	full power, fan working
RTTY, FT8, FT4, PSK	100 %	back off to roughly 500 W
FM (repeater, simplex)	100 %	back off as well

The rule of thumb for digital modes: half the rated power, full service life. Most manufacturers specify continuous-carrier operation at 50 percent of the SSB rating anyway. An FT8 transmission is 12.6 seconds of constant carrier — thermally an entirely different animal from an SSB QSO.

Drive, ALC and keying — where it gets expensive

Most amplifier damage does not come from overload in service but from incorrect wiring between transceiver and amplifier.

The rear panel is where the decisions are made: several antenna outputs, four fans, plus control, ALC and PTT interfaces. Photo: Karl-Martin Skontorp, CC BY 2.0, via Wikimedia Commons.

Drive level

The principle: you control the amplifier with the transceiver's output power, not with the ALC. Set the transceiver so that the amplifier reaches its rated output — and not one watt more. Overdriving barely raises output power but wrecks intermodulation performance.

The ALC loop

The ALC line feeds a negative voltage from the amplifier back to the transceiver, which reduces its output. It is an emergency brake, not an operating mode: the loop needs time, and during that time the overshoot has already reached the amplifier input — a well-known problem with the fast level steps of digital modes. If you constantly run the ALC against the stop, your drive level is set wrong.

https://www.youtube.com/watch?v=iA8I22DNIZQ

What ALC actually does — and what it cannot do (source: YouTube, English)

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

Hands-on: setting ALC correctly and what overdriving does to the band (source: YouTube, English)

The keying line — the most common expensive mistake

Older amplifiers switch their transmit/receive relay directly from the PTT line, in some cases at 120 volts and hundreds of milliamps. Vintage Heathkit SB-series gear is notorious for it. The transistor that switches this line in a modern transceiver is a tiny SMD device and dies from such voltages and from relay back-EMF — the classic symptom being "the transmit indicator sticks on".

The fix: a relay buffer between transceiver and amplifier (for example the Ameritron ARB-704, or kit solutions). Such buffers typically handle up to 200 V open-circuit and 300 mA. Rule of thumb: measure the open-circuit voltage at the amplifier's keying jack before connecting anything unfamiliar. Anything above 12 V means: buffer required. W8JI has a thorough write-up of the relay problem.

Hot switching and sequencing

"Hot switching" means operating the relay while RF is already present. The result is burnt relay contacts, and with LDMOS, damaged modules as well. Hence the fixed order: PTT first, RF second — with a few milliseconds of lead. Modern transceivers provide an adjustable transmit delay ("TX delay", "TX inhibit") for this. On VHF/UHF with a masthead preamplifier, add a sequencer that switches preamp, relay and RF in the correct order.

The antenna tuner in the right place

The antenna tuner belongs after the amplifier, between amplifier and antenna — and it must be rated for the full power. A tuner between transceiver and amplifier hides the real SWR from the protection circuit: the transceiver sees 1:1 while the amplifier works into 3:1. The internal tuner in most transceivers is unsuitable for that position anyway.

Staying clean: two-tone test, splatter, harmonics

Two-tone linearity test on the scope: this is what a clean envelope looks like — flattened peaks or fuzzy crossover points mean overdrive. Photo: Cqdx, CC BY-SA 3.0, via Wikimedia Commons.

The two-tone test is the classic method: two tones (say 700 and 1900 Hz) are fed in simultaneously, and the envelope on the oscilloscope immediately shows whether the amplifier is linear. Flattened peaks mean flat-topping — the amplifier is in compression and the signal is getting wide.

Without a scope you can still get a long way with an SDR and some distance: a second receiver a few hundred metres away, a look at the waterfall, a comparison of signal width with and without the amplifier. If the signal gets noticeably wider with the amplifier in line, something is wrong — usually the drive level.

Harmonics are the other issue. An amplifier without an effective output filter produces the second harmonic of 14 MHz at 28 MHz and the third at 42 MHz — right in the range where § 17 AFV demands 60 dB of suppression. Commercial amateur amplifiers have band filters built in and switched along; in homebrew designs the low-pass filter is the last component to economise on. And if band switching is manual: transmitting on 20 m with the amplifier still set to 40 m is the most reliable way to destroy the filter and your reputation in one go.

Cooling and power supply

Heat. At 60 percent efficiency, 1000 watts of RF output comes with around 700 watts of waste heat — a small fan heater in the shack, noticeable in summer and guaranteed during a contest. Forced-air cooling is mandatory, the airflow must stay unobstructed (so not inside a closed rack without extraction), and the fan should keep running after transmit. On a tube amplifier that run-on is not a comfort feature: without cooling after shutdown the tube suffers.

Mains supply. 1000 W of RF at 60 percent efficiency means roughly 1.7 kW input, about 7.5 amps at 230 volts under continuous carrier. On paper that fits a 16 A circuit (3.68 kW), but:

Dedicated circuit. Amplifier, PC, transceiver and the fridge on the same breaker is a bad idea.
Inrush current. The toroidal transformer in a tube amplifier draws 60 to 100 A briefly at switch-on. A type-B breaker will trip; type C holds. Many units include a soft-start — if yours does not, retrofit one.
Voltage sag. If the mains voltage visibly dips on transmit (lights flicker), the supply wiring is too thin. That costs output power and stresses the amplifier.
Residual current device. Interference-suppression capacitors to PE produce leakage currents; several devices together can trip a 30 mA RCD. That is not a reason to bypass the RCD — it is a reason to spread the equipment over several circuits.

The same applies with knobs on for portable and emergency operation: a 500 W amplifier from batteries or an off-grid supply draws around 70 A at 13.8 V — size cable and fuses accordingly.

Safety: high voltage, RF and exposure

Inside a 3CX1500A7 amplifier: pi-network coil, vacuum variable capacitor, chimney — and kilovolts on nearly every visible component. Photo: RSAG, CC BY-SA 3.0, via Wikimedia Commons.

High voltage

Lethal danger. Tube amplifiers run on 2000 to 4000 volts DC. The charge in the filter capacitors survives switch-off and unplugging — depending on the state of the bleeder resistors, for minutes. Reaching into the chassis without measuring first can kill you.

The rules are short and not negotiable:

unplug, wait, measure — do not trust the bleeder resistor, it may be open
discharge any residual voltage through a resistor on an insulated discharge stick, not by shorting it with a screwdriver
never defeat the cabinet interlock, not even "just to measure"
one hand in your pocket, never work alone on an open amplifier
measure the plate voltage again after discharging, before reaching in

https://www.youtube.com/watch?v=DCWP1NE2mbg

Discharging capacitors in tube equipment safely — procedure and typical mistakes (source: YouTube, English)

https://www.youtube.com/watch?v=g4SGGKL2jS4

Safety switches for RF amplifiers, demonstrated on an LDMOS PA (source: YouTube, German)

RF burns and RF in the shack

RF burns are treacherous because they go deep and barely hurt while they happen. Antennas, open feed lines and balun terminals do not get touched while transmitting. Full stop.

A related symptom is RF in the shack: tingling microphones, erratic keyboards, displays that reboot on transmit. That is not an amplifier fault but a common-mode problem that higher power merely makes visible. The cure: common-mode chokes on the feed line and control cables, and clean bonding — the common-mode indicator helps track it down.

RF exposure

Unlike Germany, where the BEMFV requires a documented site declaration above 10 W EIRP, the Austrian AFV has no dedicated RF exposure clause. That is not reassurance; it puts the responsibility entirely on the operator. The ICNIRP reference levels, which also underpin the German rules, serve as the yardstick. In practice, at kilowatt levels:

Distance. In the far field, field strength falls linearly with distance — double the distance, half the field. A few extra metres between antenna and living space beat any amount of debate.
No kilowatt balcony antenna. A loop or vertical within arm's reach is a compromise at 100 W and a problem at 1 kW — for your own family as much as for the neighbours.
Consider all simultaneous transmissions together if several antennas are operated in parallel.
Freely available calculators such as this RF exposure distance calculator give useful ballpark figures — the German limits are a sensible benchmark even without an Austrian obligation.

Grounding, bonding and lightning protection

The section that generates the most confusion — because three entirely different things share one word.

Protective earth (PE). The green-and-yellow conductor from the wall socket. It ensures the breaker trips in a fault. It is never disconnected — not even with a "ground lift" adapter to cure a hum loop. Do that and you have built a lethal fault into your shack.
Bonding. All equipment chassis — transceiver, amplifier, tuner, power supply — are tied to a common bus bar with short, wide conductors (copper strap, braid). What matters is not DC resistance but inductance: a two-metre length of thin wire is not a ground at 14 MHz, it is a choke.
RF counterpoise. What some call an "RF ground" is, with unbalanced antennas, actually part of the antenna system. A ground rod does not replace radials.
Lightning protection. A field of its own with its own standards (ÖVE/ÖNORM EN 62305). Key points: a single entry point for all cables into the building, surge arresters on a bonded bus bar at exactly that point, and physically disconnecting the coax during thunderstorms. Details in our article on station grounding and lightning protection, and for antenna supports in towers and masts.

For the amplifier specifically: it is the heaviest and best-grounded box in the shack, and therefore often the point where all currents meet. A clean star bonding scheme to a common bar — not daisy-chained device to device — saves a great deal of troubleshooting later.

https://www.youtube.com/watch?v=1UXmvDDIrc8

Grounding basics in the shack: protective earth, bonding and RF ground kept properly apart (source: YouTube, English)

https://www.youtube.com/watch?v=gso1IzgT9j8

Station grounding and lightning protection in practice: entry point, arresters, bus bar (source: YouTube, English)

Commissioning, step by step

Connect a dummy load. Check its rating — many dummy loads take 1 kW for only a few seconds. § 14 AFV requires tuning without unnecessary radiation.
Measure the PTT line. Open-circuit voltage at the amplifier's keying jack; above 12 V, connect only through a buffer.
Amplifier on standby, transceiver at low power, check the antenna SWR without the amplifier — ideally measured beforehand with a NanoVNA.
Set the band correctly — on both transceiver and amplifier. With automatic band switching, verify once that it actually follows.
Tuning a tube amplifier: dip the plate current with TUNE, then bring up output with LOAD, then retouch TUNE. Short key-downs, do not sit in the dip for minutes.
Raise the drive until rated output is reached — and stop there. Note the transceiver power setting per band.
Switch to the antenna, check SWR, then go to full power.
Set up digital modes separately: halve the power, watch the ALC indicator, reduce the audio level from the PC until no ALC action occurs.

https://www.youtube.com/watch?v=qJxWYfs4Sf4

Jim W6LG walks through tuning a tube amplifier step by step — dip, loading, retouch (source: YouTube, English)

Market overview 2026

HF, solid state (LDMOS)

SPE Expert 1.3K-FA / 2K-FA — Italian, very widespread, built-in tuner and automatic band following; the 1.3K-FA is the reference in its class
Elecraft KPA1500 — 1.5 kW with integrated ATU, excellent documentation, expensive in Europe
Palstar LA-1K — 1 kW, robust, good value
RF-KIT RF2K-S — German kit in the 2 kW class with a large, active user community; permitted as a kit under the RED exemption
RM Italy BLA-350 Plus — 300 W, 1.8–30 MHz, compact and affordable; a good way to step from 100 to 300 W
Juma PA1000 — Finnish, 1 kW, deliberately simple

HF, tube

ACOM 1000 / 1010 / 1200S — Bulgarian, robust, widespread, good spares situation
OM Power OM2500 / OM3500A — Slovak, very solid, common in contest stations
Ameritron AL-811H — 800 W, the affordable classic with four 811A triodes; simple, loud, repairable

VHF/UHF

BEKO HLV series (HLV-350, HLV-1000, HLV-1100, HLV-2000) — German manufacture for 2 m, 70 cm and 23 cm with circulator protection; the 23 cm variant is of limited use in Austria because of the 10 W limit
Mirage series — compact mobile and portable amplifiers in the 100 W class

Stay away from CB "burners". Amplifiers from the CB world — including the RM Italy KL series — are built for 27 MHz, have no band-selective filtering and produce harmonics and intermodulation far beyond what § 17 AFV allows. They are unsuitable for amateur service regardless of the wattage on the data sheet.

Used-buying checklist

ask about tube hours and check idle current — a soft tube no longer makes rated output
clarify tube availability before buying. For Russian types (GU-74B, GU-78B) that has been a serious question since 2022.
check the relays by ear and by eye — contacts burnt by hot switching are the most common hidden damage
check vacuum variable capacitors for loss of vacuum (arcing while tuning)
fans and airflow — dust in the chimney is a slow death sentence for a tube amplifier
switch through all band filters and measure on each band at low power into a dummy load
for LDMOS: test the protection circuits — into a slightly mismatched load the unit must shut down, not burn out
check power supply and transformer for hum, smell and corrosion; a failed HV transformer is often an economic write-off

The most common mistakes at a glance

bought the amplifier before finishing the antenna
connected the PTT line to a modern transceiver without a buffer
used ALC as a power control instead of the transceiver's output setting
ran FT8 at full power until the module gave up
put the tuner between transceiver and amplifier instead of after it
changed band on the transceiver but not on the amplifier
disconnected protective earth to cure a hum
1 kW into a balcony antenna two metres from the children's room
ran High Power without authorisation — the application is a formality, the lack of it is not

Sources and further reading

Fernmeldebüro: information on applying "High Power" to radio amateurs — the authoritative statement on application and prerequisites
Amateurfunkverordnung (AFV) in the RIS — §§ 13, 14 and 17 as currently in force
BGBl. II No. 61/2023 — amendment to the Frequenznutzungsverordnung 2013
ÖVSV band plan overview (PDF) — frequency allocations and power limits on one page
W8JI: Relay Interface System for HF Amplifiers — relay timing, hot switching and keying lines in detail
KK5DR: Tune-up Procedure for HF Amplifiers (PDF) — a proven tuning procedure for tube amplifiers
RF exposure distance calculator — far-field assessment for amateur antennas (German)

Image credits

Title image: OM Power OM3500A — photo: Karl-Martin Skontorp, Wikimedia Commons, CC BY 2.0
Collins 30L-1 — photo: RadiomanPA, Wikimedia Commons, CC BY-SA 3.0
SPE Expert 2K-FA, rear — photo: Karl-Martin Skontorp, Wikimedia Commons, CC BY 2.0
Two-tone linearity test — photo: Cqdx, Wikimedia Commons, CC BY-SA 3.0
3CX1500A7 interior — photo: RSAG, Wikimedia Commons, CC BY-SA 3.0

Transparency Notice

This article was researched and written with the support of AI (Claude, Anthropic). The images come from Wikimedia Commons under free licences (credits above). The embedded videos are third-party content; the respective channels are responsible for them. Statements about the legal situation reflect the position as of August 2026 and do not constitute legal advice — the binding text is the current version of the FNV and AFV in the RIS. Corrections and additions are welcome at kontakt@oeradio.at.

Der Beitrag Amplifiers: Selection, Safety and Grounding erschien zuerst auf OERadio.

Show us your boxes: the repeaters of CarinthiaMesh and the people behind them

Michael | OE8YML — Mon, 24 Aug 2026 08:00:00 GMT

On 22 August, shortly before midnight, a request went out in the Telegram group Kärnten Funkt – MeshCore: anyone running a repeater should post a photo and a few lines about it. By the next morning the channel was full of attics, spruce trees, summit masts, opened enclosures and battery packs. This article is the result.

For context: as of 23 August the Carinthian MeshCore network counts 37 active repeaters, six of them test and spare nodes. Three weeks earlier there were nine. How the network works and what you need to join is covered in MeshCore: radio without a mobile network; the growth figures are in 126.9 kilometres on half a watt. This piece is about the boxes themselves and the people who carried them up.

Where it began: Thomas, the Koralpe and the Lavant valley

Before we get to summits, one site belongs up front that appears first in no statistic and is nonetheless the starting point. Thomas runs the map and the wiki at carinthiamesh.com, the two tools that made the network visible in the first place. Without them the build-out of the past weeks would have stayed a collection of individual devices that nobody had an overview of. The fact that anyone can now look up which node forwards how much is the reason a scattering of boxes turned into a network.

It started early accordingly. Nodes were already standing in the Lavant valley in autumn 2025, when hardly anything else was running in Carinthia.

October 2025: antenna and enclosure on the mast, the solar collectors behind, half the valley in front. Photo: Thomas.

The same device from the inside: XIAO board, 3000 mAh cell, multimeter measuring. Photo: Thomas.

Koralpe, ~2,100 m: 150 km/h and a transmitter next door

The Koralpe is the eastern gateway of the network and the feed towards Styria and the rest of Austria. The site is unforgiving: wind speeds of 150 km/h and more are normal there, which is why the node deliberately sits a little lower and sheltered behind the girder, clamped straight onto the mast rather than on the supplied arm.

Then there is the 50-metre transmitter mast right next door. A 5.8 dBi antenna was taken down again for that reason: transmitting was excellent, receiving practically dead. Since 12 August a 3 dBi fibreglass antenna hangs there, measured at around 1.38 SWR.

12 August 2026, Koralpe: the 3 dBi fibreglass antenna after the swap, the wind turbines on the horizon behind. Photo: Thomas.

Sheltered behind the girder instead of on the arm. At 150 km/h, a deliberate decision. Photo: Thomas.

Lavant valley: Pölling and St. Ulrich

Both are XIAO nRF52 nodes, likewise from Thomas. St. Ulrich, at around 3,200 forwards per day, is one of the network's two eastern gateways; Pölling is the local feeder and has, according to its operator, been running for nine months without a sealed enclosure and without trouble. Bare boards survive more than people think.

Pölling: board, battery and panel under the roof overhang, fixed with tape. It has been running like that for nine months. Photo: Thomas.

On the mountain: the anchor points

Dobratsch, 2,166 m: the one everybody waited for

The Dobratsch was the target from day one. The go-ahead came on 3 August from Uwe, OE8URQ, sysop of the repeater site up there. Ten days of debate followed about whether to "sacrifice" a solar node or build something properly robust, the outcome being that on Friday 14 August a packed rucksack was waiting at the Rostratte car park at half past eight. Inside: a SenseCAP Solar Node P1.

"Rucksack packed, Dobratsch repeater portable": mast, panel and box, a summit node needs no more. Photo: Michael, OE8YML.

The first advert went out at 12:42. One minute later Klagenfurt reported back: received. From Pöckau, less than 15 kilometres away, nothing at all. The rocks of the Schütt sit in between, and they do not care that you ought to have line of sight to the summit. Observations like that are exactly why the wiki holds propagation models but the map still gets filled in by hand.

Solar operation on the Dobratsch is an interim solution. In autumn the node is to be swapped for a mains-powered device inside the container: power, internet and HAMNET are all available up there.

Gerlitzen, ~1,900 m: with an upside-down debut

Andre, OE8ASR, took on the Gerlitzen. Before the node went up the mountain it spent a few days as a test installation on a balcony in Arnoldstein, mounted on a satellite bracket from the hardware store and, according to the photographic evidence, upside down. Since 15 August the device has been in place, and the view from up there explains the range better than any field strength calculation.

The node on the Gerlitzen and what it sees: Villach, the basin, the lakes and the Karawanks behind them.

Martennock: the one with the ratchet strap

For the Spittal area the Goldeck had been sitting on the site list as an idea for weeks: anchor for the upper Drau valley, reachable all year by cable car, 23.7 kilometres of calculated clear line to the Dobratsch. What actually worked out sits a bit further down. Sergio, OE8CXC, had tried a good deal in the valley without the coverage ever becoming usable for him, and finally put his device on the Martennock as a test. Just before eleven at night on 22 August he posted a photo and two words: "temporarily qrv." On the map the node has been listed as AT-SP-Martennock ever since.

Temporary here means: an orange ratchet strap, a rock, and the lights of the valley underneath. Photo: Sergio, OE8CXC.

Göriacher Alm, 1,644 m: the workhorse

The repeater on the Göriacher Alm belongs to Dominic, OE8MDT, and by the numbers it is one of the most important nodes in the network: roughly 3,100 forwards in 24 hours, 33 neighbours, among them four Slovenian sites up to 78 kilometres away and the Koralpe at 108 kilometres. Installed on 8 August and moved a metre higher a few hours later, "thanks to my wife", as the builder noted.

The effect was immediate: devices down in the valley that had heard nothing before were suddenly getting through from indoors. The operator himself concluded that he now needs a longer ladder, the site has more to give.

Leppner Alm above Irschen, 1,761 m: pending approval

Wolfgang, OE8WBG, reported early on 8 August: "Repeater is on the mountain." For now the antenna hangs provisionally under the roof structure of a hut that has not yet had its official building approval. The same operator runs AT-VL-Altenberg, covering Millstatt, Seeboden and Ferndorf, and has offered a further site in Pusarnitz at around 550 metres that would light up the Möll valley.

Solar panel on the gable, cable through the hatch. Photo: Wolfgang, OE8WBG.

In the valley: local coverage and gap fillers

Nötsch: the busiest node in the network

The statistics are led not by a summit but by a site in the Gail valley: AT-VL-Nötsch, a Heltec V4 with a KF antenna, handles some 3,250 forwards in 24 hours.

The KF antenna in Nötsch, looking towards the Göriacher Alm. Photo: Michael, OE8YML.

The same site hosts the observer that logs the #kf channel and makes it readable for everyone at mesh.kaernten-funkt.at, including people without a device. Since mid-August there is also the MeshBot, a command bot in the #at-ktn-bot channel. It delivers weather, official severe weather warnings, SOTA summit data and the nearest amateur radio repeaters, all without a mobile network, straight over radio. What it can do is written up in the MeshBot wiki.

Pöckau: the first in the valley

AT-VL-Poeckau was online on 4 August, before any mountain had been occupied, and is still the local distributor in the lower Gail valley. Hardware: SenseCAP Solar Node P1-Pro plus a 3 dBi antenna. The operator is again Dominic, OE8MDT.

Pöckau, installed on 4 August: the chimney has been purely decorative since the heat pump arrived, the repeater has not. Photo: Dominic, OE8MDT.

Villach: KF HQ

A P1 has been sitting on a mast on the roof of Ossiacher Zeile 39/1 since 11 August. That is made possible by Günther, OE8VIL, who provides the site. The node closes the dark spot that the Dobratsch and the Gerlitzen leave right over the city: both mountains simply "shoot over" it. In autumn the antenna is due to go higher.

The mast on the roof of the KF HQ, put up on 11 August. The arm is still free, in autumn the antenna is to go higher. Photo: Andre, OE8ASR.

Waidegg: the first in the Hermagor district

On 19 August Chris, OE8CKK, put a Heltec node into service in Waidegg, cutting into the last large blank area in the Gail valley. Remarkably, its anchor is not the nearest neighbour but the Dobratsch at 34.3 kilometres, the four closer sites are all terrain-blocked. At the time of writing the node had gone quiet; anyone hearing it in that area is asked to report in the channel.

Waidegg: the first repeater in the district of Hermagor. Photo: Chris, OE8CKK.

Knappenberg: three nodes, one of them near the top

Hermann, OE8HSF, runs three repeaters around Hüttenberg. One of them, a RAK4631 with PV, sits at roughly 1,100 forwards per day, ahead of every site outside the big four. Next on his list is the Hohenwart above the Klippitztörl pass.

Knappenberg: RAK4631 in a white enclosure, panel screwed to the railing at an angle, antenna clear above the treetops. Photo: Hermann, OE8HSF.

Klagenfurt: city centre, Emmersdorf and a spruce tree

An Elecrow ThinkNode M6 is currently being rolled out on the east side of the Rothauer tower block, a club device from KÄRNTEN FUNKT, installed by Thomas. The fact that the node goes quiet in between is part of the installation.

Labelled, configured, ready for the roof: AT-K-Innere Stadt.

Christian runs three repeaters in the Klagenfurt area and is the only one able to contribute something everybody else still lacks: long-term experience. His node in the forest, about 100 metres above his house, has been running for almost a year: a RAK 4631, four 18650 cells, a 4 W panel, a step-down converter, no MPPT controller, charging straight through the board, plus a fibreglass antenna from a far-east shop. Mounted on a spruce, reachable by ladder.

The second site, right at the house in Emmersdorf, is a Heltec T114 in a 3D-printed "Hermes" enclosure with a 2 W panel. The third, in Gurnitz, was swapped for newer hardware on 16 August.

Spittal: from the sofa to the hillside

Dominik, OE8DLE, first ran his repeater in the attic on the third floor and then moved it five metres up the slope above the house, where it now hangs on a dead tree trunk. The device is a SenseCAP Solar Node P1-Pro, "the number one menu, so to speak", as he calls it. From there it reaches Sappl and Millstatt. His practical conclusion after two weeks of test drives on the A2 and A10: the zero-hop ping is close to useless as a range test, messages often get through anyway. The Hühnersberg is planned as the next site.

He also runs an observer of his own, logging what actually arrives at the site: a Heltec V4 hanging by USB on a Raspberry Pi 5 in the rack.

The observer in the rack: Heltec V4 on a Raspberry Pi 5 over USB, the patch panel above it. Photo: Dominik, OE8DLE.

Home-built: from a garden lamp into the landscape

Alongside the ready-made devices, a small production line is running on a workbench. The first "KF People Repeater" was built on 3 August: a XIAO board with an SX1262 radio module, the panel taken from a solar garden lamp bought at a hardware store, a three-euro charging module, antenna cap and mounting from the 3D printer. Printed in PETG; ASA would be better for years of outdoor exposure, but PETG has held up for years already.

The larger variant takes four 18650 cells, around twelve amp hours, charged through a CN3065 module from a 2 W panel. The charging current stays so small that frost is not a drama either, and the field data on that, including from a network in Calgary with summit sites at minus 40 degrees, is in the wiki.

Twelve amp hours in a printed box: the spare unit for Nötsch.

The home-built units are meanwhile being tested outside the workshop as well: Wolfgang, OE8WOK, in Thörl-Maglern and Gabriel, OE8IEA, in Hohenturn each have one in service and report back on how the solar supply holds up in everyday use.

That you do not need a repeater to take part is shown by Andre, OE8ASR. His companion, a Heltec V3 in a printed enclosure, simply hangs at the window, connected by two metres of RG-174 to an outdoor antenna. With that he hears the Göriacher Alm and Nötsch, both around eight kilometres away. The device is power-hungry, but it makes the point: a windowsill and a piece of coax are enough to get started.

René, OE8SRM, is going a similar way. He reflashed his existing devices from Meshtastic to MeshCore and has been QRV with a companion in the middle of Klagenfurt ever since, the hardware being a LilyGo T-Beam and a Heltec V3.

Moving from Meshtastic to MeshCore at the desk: T-Beam, Heltec V3 and enclosures from the printer. Photo: René, OE8SRM.

The companion of Andre, OE8ASR, at the window: two metres of coax are enough for two repeaters at eight kilometres each. Photo: Andre, OE8ASR.

What is still missing

Of the Carinthian districts, only Feldkirchen is left without a single repeater. Concrete entries on the list include the Hühnersberg, Völkendorf in Villach, the school cluster in Hermagor, the Hohenwart at the Klippitztörl, the Bernsteiner Ofen and the Hemmaberg. Noted as longer-term goals are the Sonnblick observatory at 3,106 metres, staffed all year, with a calculated 74-kilometre direct path to the Dobratsch, and the Golzentipp as the door to East Tyrol.

And because it belongs to an honest picture: since 23 August the wiki also holds a repeater analysis showing which sites carry the network and which merely add to the flood. By the numbers, three nodes could be switched off without anyone noticing. More repeaters are not automatically better, and anyone wondering where the limit lies will find the answer in satirical form in our cellar node.

Joining in

On Friday, 28 August 2026 at 19:00 there is an information evening on MeshCore at the KÄRNTEN FUNKT HQ, Ossiacher Zeile 39/1 in 9500 Villach. No licence, no fee, no contract, and registration is non-binding and only helps with planning.

To look around beforehand: all sites are on map.carinthiamesh.com, the running traffic in the live view, the guides in the CarinthiaMesh wiki and the channel to read along at mesh.kaernten-funkt.at. The whole thing is carried by the club KÄRNTEN FUNKT. One of the channels in use is #kf, and since recently there is also SOTA spotting over MeshCore. Questions are answered in the Telegram group Kärnten Funkt – MeshCore; everyone is welcome there, with or without a device and with or without a callsign.

Further reading on oeradio.at: MeshCore: radio without a mobile network explains the technology and how to get started, 126.9 kilometres on half a watt traces the growth of the network, SOTAmesh shows spotting from the summit without internet, and MeshCom introduces the licensed counterpart in the amateur radio bands. Anyone who prefers it with a wink will find the satire in Mesh Is Fresh.

If you have a good site but no device yet, the best thing is to ask in the group: for individual sites a solution has already been found, but nothing is promised. If you have hardware and are looking for a place for it, the wiki has a list of open sites. And if you have neither, you can still contribute what is currently missing almost everywhere: measured coverage. Drive around, take notes, report back.

73 – your oeradio.at editorial team

Transparency Notice

This article is based on the messages posted in the Telegram group "Kärnten Funkt – MeshCore" between 3 and 23 August 2026, together with the site list and repeater analysis in the CarinthiaMesh wiki, data as of 23 August 2026. The photos come from the respective operators, who supplied them for publication in response to a request in the group; credits are given with the images. Traffic figures are observer measurements and therefore a lower bound, not a complete survey. This article was researched and written with the support of AI (Claude, Anthropic) and reviewed by the oeradio.at editorial team. Corrections, missing sites and photo credits are welcome at kontakt@oeradio.at.

Der Beitrag Show us your boxes: the repeaters of CarinthiaMesh and the people behind them erschien zuerst auf OERadio.

10 days of radio roadtrip with an abrupt ending

Sigrid Magdalena | OE1YLS — Fri, 21 Aug 2026 18:30:00 GMT

30 activations

(~3000km / ~38 hours of pure driving time)

My life at the moment consists of working and operating. All right, in summer, as a teacher, it consists of operating only. It feels like I don't have a private life any more. I've already infected everyone around me with radio vocabulary, and even my daughter's grandmother no longer asks "How are you?" but "Where are you operating from today?", and instead of "Have a nice holiday" I get "Good radio contacts". My older sister loves the APRS Tracker so she can always check whether I'm still alive, and a dear non-ham friend occasionally writes "Turrach reports 5.9 periodic! seventythreeee". The same one is also calling me YLSi more and more often.

Actually my motto has always been "Why do it the easy way when the hard way works too". Now let's turn the tables for once. Up to now it was primarily about the hiking for me - no matter how long, how far, how high or how hard - and only secondarily about the radio. After roughly 50,000 vertical metres of ascent in my legs this year, though, my knees above all are screaming for a break. Somehow the pine resin ointment and comfrey ointment aren't enough any more to get the pain under control.

The perfect time, then, to set off on the radio roadtrip I'd planned. Everything was supposed to revolve around activating three 4000-metre summits in Switzerland. I've been planning this project with a French friend since January. The date was set for mid-August. Two weeks beforehand the mountain guide cancels the tour, because the crevasses are getting more and more dangerous. He replaces Breithorn, Pollux and Castor with a different four-day tour. But since there isn't a single SOTA summit in it for me, I pull out.

My trip actually starts on 8 Aug with Fieldday 69. That day I drive off with all my kit towards the Koralpe, activate the Gr. Speikkogel, the Moschkogel and the Handalm and then drive on a bit further to the Styrians' fieldday. Sadly I don't get to put a single face to the familiar voices. OE6TNO, Jürgen, is even there at the same time as me, and yet we still manage not to bump into each other. I can't stay long either, because the same day it's on to Vienna. Six hours of driving in one day is enough for me as a start. I stay one night in Vienna and on 9 Aug at 7 a.m. I'm already sitting in the car again.

Moschkogel (OE/ST-134), 8 Aug 2026

Day 1 (9 Aug) - Bayrischer Wald

Brotjacklriegel (DM/BW-012)
Fürberg (DM/BW-324)
Eschenberg (DM/BW-271)
Kronberg (DM/BW-263)

I only pick a few summits in the Bayrischer Wald at random the evening before, around 10 p.m. You really are spoilt for choice up there, and all those little 10-point summits are simply too tempting not to make a detour for. I definitely don't take the time to plan a proper tour. Bad mistake, because on the very first summit (Brotjacklriegel) I'm presented with the bill. An enormous source of interference spoils my very first activation in Germany. I turn the mic gain up to 90% and even the strongest stations sound extremely faint when I scan the frequencies. DC0RB Wolfgang saves me from a complete failure, and from that moment at the latest I'm very grateful for his tips.

How quickly you can be up and down again on a mountain worth 10 points! I'm fascinated. I can beat the Alert times without having to rush, and I don't even have to eat while walking the way I normally do.

Summits 2 and 3 (Fürberg, Eschenberg) win me over again and I'm glad they're in the forest where it's shady. My highlight QSO is with IN3KSK Paolo, who makes it all the way from Bolzano to me in the Bayrischer Wald with 10W and a report of 57.

And when I manage the Kronberg as an encore too and sit relaxed on the bench next to the summit cross, my conclusion at the end of day 1 is: only 500 vertical metres for 4 summits and no pain. On the other hand I feel extremely silly for not really having earned the points. My non-ham friend says I should be ashamed of myself for scrounging points on those molehills. He's not wrong. When you're normally used to a walk-in of several hours, they don't just feel like cheap points, they feel like a gift. By day 5 at the latest I'm thinking differently, because a roadtrip with lots of activations, serious heat and many kilometres of driving is genuinely exhausting.

Brotjacklriegel (DM/BW-012), 9 Aug 2026

Kronberg (DM/BW-263), 9 Aug 2026

Day 2 (10 Aug) - Schwäbische Alp

Römerstein (DM/BW-078)
Herrenwald (DM/BW-852)
Burg Hohenzollern (DM/BW-846)

After a night somewhere in the forest, I'm off again at 6h30 - a bit more than three hours of driving on the German Autobahn. Even a Smart goes whooshing past me on the left at 150kmh. For 8 years I drove this stretch several times a year from France to Austria, when I was living in Burgundy with my daughter. For 8 years we hardly ever left the motorway on the way. And now, after 8 years back in Austria, I finally get to drive towards my second home again, and I use every opportunity to finally explore the areas off the motorway a bit. Once again I love Sotlas for that.

In the Schwäbische Alb too I only pick a few summits at random, first coming across Burg Hohenzollern and then planning the rest around it. On the Römerstein, after a 10-minute walk in, I'm alone on a meadow with a barbecue spot and enjoy the absolute quiet while operating. On to the Herrenwald - 5 minutes down, 30 minutes' drive, 20 minutes up, set up and operate in the middle of the forest. The clouds look a bit threatening, but it's only back at the car park that it starts to rain lightly. On the drive to Burg Hohenzollern it looks pretty black above the castle as well. Never mind, if I can't operate then I'll do some sightseeing in the castle.

No sooner said than done. Park, buy a ticket, walk up for 15 min. Inside the castle I throw the EndFed over the castle wall and try not to be in anyone's way. I still get asked about my fishing several times. The SWR is a bit high and the thick castle wall means I can't get out in every direction either. After 3 hard-won QSOs it starts raining again and I quickly pack up. Under a tree I pull out the handheld and call in what feels like 100 times until finally 2 pensioners take pity on me and answer. But the conversations are all the nicer for it, and one of them gives me a tip for the next day in the Schwarzwald: the Belchen.

Until the rain has passed I do a tour of all the floors of the castle, and back at the car park I look up the Belchen and this time consider activating DM/BW-001, 002 and 003. I set up camp below the Feldberg (001) and have to note, to my dismay, that here too there's a transmitter mast on the summit again.

The car is quickly converted back into a sleeping place. Fold the seats down, inflate the mat, cook something, eat, brush teeth, make notes, earplugs in, sleep. The simpler the better.

Schwäbische Alb, 10 Aug 2026

Römerstein (DM/BW-078), 10 Aug 2026

Burg Hohenzollern (DM/BW-846), 10 Aug 2026

Herrenwald (DM/BW-852), 10 Aug 2026

Day 3 (11 Aug) - Schwarzwald

Feldberg (DM/BW-001)
Herzogenhorn (DM/BW-002)
Belchen (DM/BW-003)
Le Molkenrain (FL/VO-017)

Since I'm already on the spot today, I can be QRV on the first mountain at 8 a.m., after sunrise and breakfast. I strolled up the 15 min. of ascent to the summit at a leisurely pace. Bit by bit I'm getting used to these luxury walk-ins.

At that time of day I'm not expecting very much and I'm astonished that quite a few of the by now familiar voices are QRV on 20m, like SQ9CWO Jan, SM4VBO Stefan, EA3EVL Pablo, DL9NCI Georg, HB9DIZ Markus (who also „accompanies" me via Signal for the whole trip) or F4WBN Christian (with a standard report of 59 from my side). That makes me really happy, and when I then also get to have a thoroughly nice and long QSO on 2m with the Swiss mountain nut René HB9NBG, I'm completely blown away. He recommends a few 3000-metre summits in Switzerland to me, which I note down for the drive back from France.

On to 002. Here the walk in is a touch longer at 35 minutes and a huge summit cross and a bench for sitting and logging are waiting for me. The mobile signal isn't always particularly good, but somehow I manage to spot every time.

Off to 003, where a gondola takes me up and only 15 minutes of climbing are left.

In the gondola on the way up I look at what the next day might have to offer. I swipe further west on Sotlas and look for Le Grand Ballon in the Elsass. I quickly find a few other hills as well and ta-da, the next day is planned.

It's such a big help when you find a track on Sotlas. It saves you so much time and I'm really grateful for it. That's exactly why I always upload tracks and descriptions or photos when there aren't any yet. All in all that's really not a small amount of work (at least with my number of activations), but I hope that someone will find the tracks as helpful as I do.

Thanks to the short walking times the 3 summits are activated faster than planned and the journey continues towards France. I drive as little motorway as possible and get extremely sentimental once I'm finally on French soil. I can hardly pull myself together for almost 2 days and keep fighting back the tears - even while operating.

Since I arrive at the car park where I want to sleep 2 hours early, I set off once more and after 20 minutes I'm on the Molkenrain. And so I activate my first French summit. The propagation isn't particularly good, but it still turns into 6 QSOs.

Feldberg (DM/BW-001), 11 Aug 2026

Autobahn in Germany towards France

Day 4 (12 Aug) - Elsass

Le Grand Ballon de Guebwiller (FL/VO-001)
Le Storkenkopf (FL/VO-078)
Klintzkopf (FL/VO-079)
Le Lauchenkopf (FL/VO-081)

Now I'm right in the middle of walk-in paradise. To each of the planned summits it's a maximum of 20 minutes.

Today I'm even back at the car at 14:45 after the 4th summit. Two more summits would easily have fitted in (hi). I prefer a chilled afternoon including a bath in a mountain stream and a siesta on the picnic blanket in the middle of the forest. Highlight 1 of the day: on the road from summit 2 to 3 I get overtaken by 2 cyclists while going downhill at 60km/h. Highlight 2: before summit 4 I meet F4SCQ Laurent, whom I'd already worked from the previous summits, and so I also get a Complete in France straight away, because he's a summit ahead of me twice over. We chat for about 20 minutes and I'm delighted to finally run into another ham on the mountain by chance.

Le Grand Ballon (FL/VO-001), 12 Aug 2026

Le Klintzkopf (FL/VO-079), 12 Aug 2026

Day 5 (13 Aug) - Elsass

Rothenbachkopf (FL/VO-080)
Le Rainkopf (FL/VO-170)

I sleep so well that I don't wake up until 7h30. The first Alert is set for 8h30. Since I'm not going to make that anyway, I don't even bother to hurry. Today the production-line operating is getting on my own nerves, but now I'm here anyway. I'll do 2 more summits in the Elsass, then I've had enough. I'd rather look into whether I can find a mountain somewhere in France for a first activation.

My first summit today is apparently a hotspot for paragliders, because they're flying around above my head the whole (radio) time.

It's only bearable in the shade and the alpine meadows here are completely brown and extremely dry.

How cyclists and runners can stand the midday heat on the alpine roads here is a mystery to me. After almost 3 hours of activating on the Rainkopf in the blazing sun I'm staggering towards the car myself.

The heat is brutal, and I lie down in the same stream as the day before. At 40 degrees on the motorway, after this longer cooling-off break in the stream, I carry on towards Burgundy.

After 4h30 of driving I sleep in the middle of the forest again, 10 minutes from the village where I'm starting the next day. Final highlight: 2 long, fat shooting stars that I get to see out of the rear window around 11 p.m.

Rothenbachkopf (FL/VO-080), 13 Aug 2026

Le Rainkopf (FL/VO-170), 13 Aug 2026

Camping sauvage

Short breaks

Day 6 (14 Aug) - Parc Naturel du Morvan

Tureau des Grands Bois (FL/VL-003)
Haut Folin (FL/VL-001)
Mont Prenelay (FL/VL-022)
Mont Beuvray (FL/VL-002)

I know the Morvan national park from climbing and I'm really looking forward to operating here. Today it occurs to me that I actually used to have bad knee pain. Hallelujah, it's gone now! On the other hand, no mountain where I'm activating from here on is higher than 900m any more, and since the start of the radio trip I've been able to go operating in my running shoes instead of my hiking boots.

The day begins quite promisingly when the local postman wishes me a nice hike and a lady wishes me good morning out of her house. But what can I say - yet another transmitter mast on the summit. The operating only creeps along and on 2m I hear several stations that absolutely cannot hear me. Never mind, it starts to rain and I pack everything up again.

On the Haut Folin I can even set the antenna up right next to the car and operate from the car park. In return there's a bit more walking again on the Mont Preneley. This is where the river Yonne rises and the forest is typical of the Morvan. A mixture of enchanted and bewitched, where the moss grows up the trees and gnomes and pixies could jump out from behind a tree at any moment. On 2m I have several stations coming back to me and I have to grin, because they obviously love a chat and my QSOs feel like they last forever. The day before I'd had the idea of noting down a few local callsigns via aprs.fi and then writing to them via QRZ, asking them to pass the word on in case anyone wanted to work me. Even though it's almost 40 degrees on the last mountain, Beuvray, it's these local contacts above all that make me happy. On every activation somebody different comes back to me on 2m.

In the late afternoon I drive another 1h30 towards Charolles. I left half my soul here when I moved back to Austria with my daughter in 2018. I sleep at friends' place and of course get pretty nostalgic again. But my heart aches most of all because the normally so beautiful green landscape is completely brown and burnt.

Mont Preneley (FL/VL-022), 14 Aug 2026

Mont Beuvray (FL/VL-002), 14 Aug 2026

Days 7 & 8 (15 + 16 Aug) - Charollais, Brionnais

Grande Roche (FL/VL-105)
Mont Saint Cyr (FL/VL-030)
Butte de Suin (FL/VL-039)
La Mère Boitier (FL/VL-031)

In my naivety I believe I can activate 2 summits per day and still meet friends in the afternoon/evening. I only told 2 people that I was in the area. Well, the news obviously spreads all by itself, and after 2 days and a blistering heat of 40 degrees the fuss (however kindly it's meant) is too much for me and I flee again. Too much social contact is extremely overwhelming for me.

Highlight 1 of the activations in the Charollais-Brionnais area: while I'm on the Butte de Suin, F4ELU Roger drops by in person. From this summit I get 10 QSOs on 2m straight away, which makes me really happy, and from now on I'm probably known in the area too, because my message obviously got spread around via social networks.

Highlight 2, from the summit La Mère Boitier, is the S2S on 2m and 70cm with HB9HCS Stefan, 212km away. He's just as pleased about it as I am.

But now that's definitely enough of the little hills around here. My favourite friend writes to me: "A 600-er and a 758-er in one day - is that still sensible at your age?"

All right then, something proper it has to be again. On Sotlas I zoom into the sea of red dots in the French Alps and search specifically for a mountain for a first activation. I find one pretty quickly. Le Grand Coin, 2,730m high, 1,200 vertical metres, 4 hours of walking in. Now that does sound rather more proper than 600m and 758m.

3h15 of driving, past a burning lorry lying across the road on the motorway, over a winding alpine road, find a sleeping spot above Saint Jean de Maurienne, convert the car and watch the thunderstorm from inside it „et bonne nuit".

Butte de Suin (FL/VL-039), 16 Aug 2026

La Mère Boitier (FL/VL-031), 16 Aug 2026

Alpine road in France

Day 9 (17 Aug)

Le Grand Coin (F/AB-217)

Now it's back to more vertical metres, carrying more water, more clothes, more weight - same old same old. I'm out on the mountain the whole morning alone with me, myself and I, but in return I see a marmot, 3 chamois, an ibex and what I first think is an eagle. But when one eagle turns into 3, then 5 and then 9, I become more and more convinced that they must be vultures. They're huge and really beautiful, circling above me like that. I don't do them the favour of dropping dead, though. ;)

The weather is supposed to hold until the afternoon, but when it turns really black before 10 a.m. I check meteoblue once more. Dammit - now it's raining from 9 a.m. with a probability of 75%. I pant my way up even faster, and after all the activations of the last few days at least setting up the antenna goes like clockwork. I'm QRV at 10h40, I'm absolutely thrilled about the first activation and just before 11 I have to pack up again in a hurry. It gets so black and the fog takes away all my visibility. I quickly try my luck on 2m and then I'm already sprinting off again. First 900m along the ridge, almost flat, then quite a long way down with no shelter, tree, rock or refuge. This is not where I want to get caught by a thunderstorm. After 30 minutes it does get a bit brighter again, though, and I come out of the fog, which is now only wrapping the mountain tops. There's still time for a few bilberries, and only 100m before I get to the car park does it start raining lightly. Phew! Lucky! But ouch, my knees...

I sit down in the restaurant at the Col du Chaussy, eat something and wait until the rain clears off again. It keeps raining for the rest of the afternoon and I get my head down in the car. Before that I look for a good walking route up the next summit and hope for better weather for the next first activation.

Le Grand Coin (F/AB-217), 17 Aug 2026, with Le Bellachat in the background

Le Grand Coin (F/AB-217), 17 Aug 2026

Day 10 (18 Aug)

Le Bellachat (F/AB-196)

Today we push the positive vertical metres up a bit further to 1,370, and the summit is higher than yesterday's too at 2,822m. That means a longer walk in, and the weather has to hold. Until 12h30 this is the absolutely most beautiful and best radio day of the tour. After that it turns more into a nightmare. The ascent is so lovely that it feels like I reach for my phone every 2 minutes to take a photo. The landscape is breathtakingly wild, untouched and beautiful, and I meet hundreds of sheep, more than 10 ibex (2 of them 10 metres away) and several marmots (one only 5 metres away). The weather is a dream and I arrive on the summit overjoyed. The first activation works out, and at the end I deliberately wait another half hour for IK2LEY Fabio so that I can go QRT with 50 QSOs.

And yes, after that I unfortunately get punished for wanting to take a short cut on the way down. It's so steep that I slip twice in the tall grass. In the process I lose my phone out of my trouser pocket. By the time I notice, I have no idea any more exactly where I slipped. First I search back and forth along the route. After a while I walk over to the alpine dairy hut I'd seen on the way up, to ask for a phone so I might be able to locate my own. The dairywoman is super kind and lends me her phone. But since my phone is on silent and in flight mode, only the last position can be determined, not the most recent one. That's far too imprecise, and after 5 hours of searching and more than 2,000 vertical metres done in total, I give up. Besides, there are supposed to be a lot of wolves here and I don't want to meet one when night falls. I take the dairywoman's phone back, start the descent, meet 2 more hunters who are walking up in the evening (maybe they're out hunting wolves) and don't get back to the car until late.

Around 8 p.m. I decide that it's going to be really hard to keep driving and operating for a few more days without a phone, and set off towards Italy. First through the Tunnel de Fréjus, then towards Turin and Milan, then towards Venice. At around half past midnight and half past four in the morning I lie down for an hour each time and I'm home at 9 in the morning. I can't rest much, because now I have to go hunting for photos in the cloud and of course I need a new SIM card etc. To my dismay all the photos from the last 8 days, meaning all the photos I took in France, weren't synchronised. A few that I'd sent get sent back to me via WhatsApp and Signal, but I'm endlessly sorry about the last day above all. I sent a single photo to IN3JIB Julian right while logging, when a message from him pops up: „you really are unstoppable". Yeah, and that's how quickly I became stoppable.

Le Bellachat (F/AB-196), 18 Aug 2026

Conclusion

Switzerland, which was actually supposed to be the goal of this trip, is something I've now genuinely only driven around. In return I covered countless kilometres in 10 days, spent around 38 hours in the car (and slept in it as well), activated 30 summits, logged lots of lovely QSOs and crossed half of Germany and France in the process, including a spontaneous night drive right across Italy. So the planned 4000-metre project turned into something completely different.

I now know that 10-point summits can be activated quickly, but also that a roadtrip with heat, driving and activations at high speed clearly takes it out of you too.

In this form I don't need a radio roadtrip like that a second time. Next time I'd rather pick one area again (like the Abruzzo in July), stay there longer, drive fewer kilometres and in return spend more time on the mountain again. As tempting as all those red dots on Sotlas in the Bayrischer Wald, in the Schwarzwald and in the Elsass were – the two first activations on Le Bellachat and Le Grand Coin were definitely my highlight of the whole tour.

And one thing is certain: the next trip is going to Switzerland.

All activations

73 de Sigrid Magdalena OE1YLS

This is a guest post by Sigrid Magdalena, OE1YLS. Do you also have a story from the mountain or from the shack? Write to us at kontakt@oeradio.at!

Der Beitrag 10 days of radio roadtrip with an abrupt ending erschien zuerst auf OERadio.

Running OpenWebRX+: Your Own Web-Based SDR Server

Michael | OE8YML — Thu, 20 Aug 2026 07:00:00 GMT

Imagine sharing your radio receiver with the entire world — directly through a web browser, without anyone needing to install software. That is exactly what OpenWebRX+ enables: an open-source project that turns a Raspberry Pi and an inexpensive SDR receiver into a fully fledged web-based SDR server. Multiple users can simultaneously browse frequencies, watch waterfall displays and decode digital modes — all within a web browser.

What is OpenWebRX+?

OpenWebRX was originally developed by Andras Retzler (HA7ILM) as a university thesis in Hungary and released in 2014. After a period of stagnation, Jakob Ketterl (DD5JFK) took over development and brought the project to a professional level with package management, Docker images and a modern web interface. In 2022, Marat Fayzullin (KC1TXE) started the fork OpenWebRX+, which has since grown rapidly and offers numerous additional features.

OpenWebRX+ positions itself as a "tricorder for the radio spectrum" — a universal tool intended to decode as many communication protocols as possible without having to cobble together different programs. The project was honoured with the Amateur Radio Software Award in 2024.

State of development (August 2026): The fork is actively maintained and version numbers move on almost weekly. The current series is 1.2.x, the ready-made SD card image for the 64-bit Raspberry Pi arrived in June 2026 as 1.2.117, and 1.2.119 followed shortly after with a first P25 decoder. The licence is AGPL-3.0.

Jakob Ketterl's original looks different. Its last regular stable release was a security hotfix in October 2023, and while the repository still sees activity, the release cycle has effectively stopped. Anyone setting up from scratch today therefore takes OpenWebRX+. One thing matters here: the two package repositories do not get along, so you add either one or the other, never both.

Features: What OpenWebRX+ Can Do

The feature list of OpenWebRX+ is impressive and grows with every release. Here are the key highlights:

Digital modes — decoded directly in the browser:

Amateur radio modes: FT8, FT4, WSPR, JT65, JT9, FST4, FST4W, Q65, CW (Skimmer), RTTY, SITOR-B, JS8Call
Digital voice: DMR, D-Star, YSF (Yaesu System Fusion), NXDN, M17, FreeDV
Packet/APRS: APRS decoding with map display and APRS-IS integration
Image decoding: SSTV (Slow Scan Television) and weather fax (HF FAX)
Aviation: HFDL, VDL2, ACARS, ADS-B
Paging and IoT: POCSAG, FLEX, ISM band decoding via rtl_433
Maritime: AIS (Automatic Identification System)
Others: RDS (FM radio text), SELCALL (DTMF, EEA, EIA, CCIR), SAM

User interface and operation:

Multi-user waterfall: Multiple users can listen to different frequencies simultaneously
Noise reduction: Built-in noise reduction algorithms for improved reception
Scanner: Automatic scanning across frequency ranges
Audio recording: Record received audio directly in the browser
Chat: Integrated user chat between connected users
Keyboard control: Comprehensive keyboard shortcuts for fast operation
Map integration: Display decoded stations on an interactive map

Supported Hardware

OpenWebRX+ works with a wide range of SDR receivers — from the budget-friendly RTL-SDR to high-end devices. Here is an overview:

Getting started costs about 30 euros: an RTL-SDR V3 with adapters is plenty for a first WebSDR. Photo: Joeceads, CC BY-SA 4.0, via Wikimedia Commons.

RTL-SDR (V3/V4): The classic entry-level choice. Frequency range 500 kHz to 1.7 GHz, costs around 30–40 euros. Ideal for VHF, airband, amateur radio bands and ISM
SDRplay (RSP1A, RSPdx, RSPduo): Wideband receivers covering 1 kHz to 2 GHz with 12-bit ADC and excellent value for money
Airspy (HF+ Discovery, R2, Mini): Excellent HF receivers with very low noise floor, ideal for shortwave reception
HackRF One: A transmit-capable SDR (1 MHz to 6 GHz) that can also be used as a receiver
Hermes Lite 2: Open-source HF transceiver with HPSDR protocol, directly supported
Web-888: A dedicated WebSDR receiver with built-in FPGA (Zynq7010), covering 1 kHz to 62 MHz plus VHF, with OpenWebRX+ pre-installed
Others: Perseus, FiFi-SDR, Radioberry, RTLSDR-Airband, PerseusSDR

Tip: For a pure shortwave WebSDR, the Airspy HF+ Discovery is the best choice. For a wideband server covering VLF through UHF, an SDRplay RSPdx or an ensemble of multiple RTL-SDR dongles with different antennas works well. You can find a detailed SDR comparison in our separate article.

The antenna matters more than the receiver

This gets overlooked while tinkering: a 300 euro SDR on a poor antenna loses against a 30 euro stick on a good one. For a wideband WebSDR on VHF and UHF a discone is the obvious choice, because it receives reasonably evenly across several octaves and hears in all directions. For shortwave people usually run a long wire or an active loop, ideally with a common mode choke so the receiver does not end up listening to the house wiring.

Discone on the roof: wideband, omnidirectional and therefore the typical antenna for a VHF/UHF WebSDR. Photo: mr_t_77, CC BY-SA 2.0, via Wikimedia Commons.

And a practical point: once the receiver runs around the clock, you quickly notice how much noise your own house produces. Switching power supplies, LED drivers and chargers are the usual suspects. Before investing in better hardware it pays to spend an hour switching off one circuit after another at the fuse box while watching the waterfall. Whatever is left can partly be tamed with the built-in filters, and how far modern AI-based noise reduction has come is something we looked at separately.

Installation: Three Paths to Your Own WebSDR

OpenWebRX+ offers three installation paths, depending on your experience and intended use:

1. Raspberry Pi Image (the easiest way)

For the quickest start, pre-built SD card images are available. Simply write one to a microSD card, insert it into your Raspberry Pi, connect an SDR dongle — and you are ready to go. Both 32-bit and 64-bit images are available. A Raspberry Pi 4 with at least 4 GB RAM is recommended. RTL-SDR and SDRplay devices work out of the box without additional configuration.

2. Debian/Ubuntu Packages

For existing Linux servers, ready-made packages are available for Debian Bookworm/Trixie and Ubuntu 22.04/24.04 on amd64, arm64 and armhf architectures. Installation uses the official PPA repository:

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys ...
sudo add-apt-repository ppa:luarvique/openwebrxplus
sudo apt update
sudo apt install openwebrx

After installation, the server is available at http://localhost:8073.

3. Docker (ideal for existing servers)

Docker is the most flexible solution, especially when other services are already running on the server. A minimal docker-compose.yml looks like this:

version: "3"
services:
  openwebrx:
    image: luarvique/openwebrx-plus:latest
    ports:
      - "8073:8073"
    devices:
      - "/dev/bus/usb:/dev/bus/usb"
    volumes:
      - "./settings:/var/lib/openwebrx"
      - "./tmp:/tmp/openwebrx"
    restart: unless-stopped

Run docker compose up -d to start the server. USB devices are passed directly to the container, and configuration persists in the local settings folder. Docker images are available for x86-64, ARM64 and ARM32.

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

Tech Minds walks through the feature set and the Raspberry Pi setup (EN)

Configuration and Fine-Tuning

After installation, all configuration is done through the web interface — no need to edit configuration files (although that remains possible).

SDR Profiles: Under "Settings - SDR Devices and Profiles" you create one or more profiles for each connected receiver. A profile defines the frequency range, sample rate and display parameters. A single RTL-SDR might have three profiles: the 2-metre band, the 70-centimetre band and the airband.

Bookmarks: OpenWebRX+ knows three types of bookmarks. Band plan bookmarks come from the integrated band plan database and show which frequencies are assigned to which services. Server bookmarks are defined by the administrator in bookmarks.json and appear for all users. Client bookmarks can be set by each user individually — they are stored in the browser.

Background decoding: One of the most powerful features. When enabled, OpenWebRX+ decodes all configured digital modes around the clock — even when no user is connected. This allows the server to continuously collect FT8 spots across all bands and forward them to PSKReporter. The scheduler allows you to define which profiles are active at which time of day — with automatic calculation of sunrise and sunset for optimal band selection.

User management: Administrator accounts can be created and managed through the web interface. Public access can also be controlled — from completely open to password-protected.

Network Setup: From LAN to the Internet

OpenWebRX+ listens on port 8073 by default. Several proven methods exist for internet access:

Port forwarding: In the simplest case, port 8073 is forwarded in the router to the server's internal IP address. For HTTPS, a reverse proxy is recommended.

Reverse proxy with Nginx: WebSocket support is essential — without it, the waterfall display will not work:

location / {
    proxy_pass http://127.0.0.1:8073/;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "upgrade";
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
}

Cloudflare Tunnel: An elegant solution without port forwarding. A cloudflared service connects the local server to Cloudflare, which provides access via a public domain. WebSocket is fully supported. This method is particularly suitable when you do not have a static IP or prefer not to configure your router.

HAMNET: If you have HAMNET access, you can make your WebSDR available through the amateur radio data network — independent of the internet.

Austrian WebSDRs Running OpenWebRX+

Austria has an active WebSDR scene. Here are some examples of running OpenWebRX installations:

OE3XHU (Hollabrunn): Operated by OE3TEC with multiple RTL-SDR sticks and a Moonraker Skyscan antenna, receiving from 25 MHz to 1,300 MHz plus a longwire for HF. Available at vhf.oe3xhu.at
OE3XNR (Nebelstein): Located at 1,009 m elevation in the Waldviertel region (JN78jq). Available at sdr.oe3xnr.xax.at
OE6XUG (TU Graz): Operated at the Graz University of Technology Lustbuehel Observatory (JN77rb, 480 m). Multiple SDR receivers covering different bands
OE4XLC (Allhau): Classic WebSDR in southern Burgenland, operated by OE4RLC
OE3XSA (Krems-Egelsee): OpenWebRX+ at 450 m elevation (JN78sk)

A complete and up-to-date list of all WebSDR receivers worldwide can be found on ReceiverBook (receiverbook.de) — the directory maintained by the OpenWebRX community. You can also register your own receiver there.

A continuously maintained overview of Austrian receivers lives on our own directory page WebRX Austria, which is also listed in our tools overview. If you run a receiver that is missing there, a short mail to the editorial team is enough.

Performance Tips for Stable Operation

A WebSDR server ideally runs 24 hours a day. To ensure reliable operation, here are some proven tips:

Ethernet over WiFi: The continuous data streams from SDR benefit enormously from a stable wired connection. WiFi latency causes dropouts in the waterfall display
Reduce FFT size: A smaller FFT size (e.g. 4096 instead of 8192) significantly reduces CPU load at the expense of frequency resolution in the waterfall
tmpfs for /tmp: Move temporary decoder files to a RAM disk to protect the SD card: tmpfs /tmp tmpfs defaults,size=256M 0 0
Limit background decoding: Do not activate all modes on all bands simultaneously — even a Raspberry Pi 4 will struggle
Cooling: A passive heatsink or a quiet fan significantly extends the Raspberry Pi's lifespan during continuous operation
Powered USB hub: When using multiple SDR dongles, use an active USB hub to avoid voltage drops

Public or Private? Reporting and Community

A WebSDR can be operated purely privately — only for your own remote access. However, most operators choose to make their receiver publicly accessible and thus contribute to the amateur radio community.

ReceiverBook: The directory of the OpenWebRX community. Register your receiver there so that other radio amateurs can find it. Registration is free and displays your location on a world map.

PSKReporter: When background decoding is enabled for FT8/FT4/WSPR, OpenWebRX+ can automatically forward decoded spots to PSKReporter. This way you contribute to global propagation monitoring.

APRS-IS: Decoded APRS packets can be forwarded to the APRS Internet System — turning your server into an iGate.

User limits: Depending on hardware, the number of simultaneous users can be limited to ensure quality for everyone. A Raspberry Pi 4 typically handles 5–10 concurrent listeners.

OpenWebRX+ Compared

OpenWebRX+ is not the only WebSDR platform. Here is a brief comparison with the alternatives:

KiwiSDR: A dedicated hardware solution (approx. 300 USD) with its own BeagleBone board and 14-bit ADC. Receives 0–30 MHz with full bandwidth simultaneously and supports up to 8 concurrent users. Excellent for HF but limited to shortwave and more expensive than an RPi-based solution.

WebSDR (PA3FWM): The original WebSDR software by Pieter-Tjerk de Boer. Supports many simultaneous users but is closed-source and only made available to selected operators.

Web-888: A dedicated WebSDR receiver with built-in FPGA (1 kHz–62 MHz + VHF) that comes with OpenWebRX+ pre-installed. A "plug and play" solution — ideal for anyone who does not want to configure a Raspberry Pi.

OpenWebRX+ has the advantage of being open source, running on inexpensive hardware, covering all frequencies from VLF to UHF and offering the broadest range of digital decoders. Active development by Marat Fayzullin (KC1TXE) and the community ensures regular updates.

Project Idea: Your First WebSDR in One Hour

With the following setup, you can have your own WebSDR running in about one hour:

Hardware: Raspberry Pi 4 (4 GB), RTL-SDR Blog V4, dipole antenna, power supply, Ethernet cable
Image: Download the OpenWebRX+ Raspberry Pi image and write it to a microSD card (e.g. with Balena Etcher)
Boot: Insert the SD card, connect the RTL-SDR, plug in Ethernet and power on
Access: Open http://openwebrx:8073 or the Pi's IP address in your browser
Configure: Create an admin account, set up an SDR profile, add your first bookmarks
Enjoy: Watch the waterfall, click on signals, let FT8 decode automatically

For remote access, set up a Cloudflare Tunnel or port forwarding afterwards. And once the server is running stably, register it on ReceiverBook and share it with the world.

OpenWebRX+ turns a modest Raspberry Pi into a powerful radio monitoring station. Whether you want to share your own receiver, collect propagation data or simply listen to your antenna while away from home — this open-source project provides everything you need. Combined with an affordable RTL-SDR, the barrier to entry is low and the possibilities are virtually unlimited.

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

Step by step: setting up OpenWebRX+ with an RTL-SDR (EN)

https://www.youtube.com/watch?v=QRcY59ktoqU

The minimal build from Raspberry Pi and RTL-SDR at speed (EN)

Read on at oeradio.at

73 – your oeradio.at editorial team

Transparency Notice

This article was researched and written with the assistance of AI (Claude, Anthropic). The editorial team has reviewed and edited all content. Despite careful review, occasional inaccuracies may occur — we welcome corrections via email to kontakt@oeradio.at.

Der Beitrag Running OpenWebRX+: Your Own Web-Based SDR Server erschien zuerst auf OERadio.