Amateur Radio

Is anyone around here playing around with TETRA, I pulled a Hytera PTC760 FxB1 radio from the trash at work and learning my way into that technology. if someone has some hints or tips I’d highly appreciate them.

We'll walk you through adding a Telemetry module to your FakeTec Meshtastic Device to measure air pressure, temperature, and humidity.

Nets and conversations on repeaters in the Wake County, NC vicinity are getting disrupted by a troublemaker. The conventional wisdom is not to feed the trolls.

Transcript of short article about interference follows:

When You’re the Victim of Intentional Interference

The question of why one ham intentionally interferes with another would make a fascinating study topic for psychologists. The answer usually involves anger of some sort-either anger at you personally, or anger at the world in general. Amateur Radio is the ideal medium for those who want to act on their frustrations with little fear of suffering the consequences. A ham who wouldn’t dare insult you to your face has no problem anonymously garbling your transmissions!

This type of ham gains pleasure from his actions only when you acknowledge them. He craves attention and your angry response gives him exactly what he needs. The trick is to do everything possib!e to ignore him. Try to continue your conversation as best you can, working around his interruptions without comment If the interference is so bad that you cannot continue, move to another frequency.

I know it’s difficult to hold your tongue in the face of such rude behavior. By ignoring his antics, however, you’ll rob him of the pleasure he seeks. Eventually, he’ll become bored and move on. That’s the worst punishment you can inflict! - WB8IMY

This guide details building a low-cost Meshtastic node using an NRF52840 Pro Micro, HT-RA62 LoRa module, and FakeTec PCB. Total cost is around $11. Assembly requires SMC soldering skills, followed by bootloader updates and Meshtastic firmware installation.

Hello, this is for ham radio enthusiasts from India. VU2LVJ is starting a free online learning program for the Amateur Station Operators Certificate (ASOC) exam in India. If someone is interested you can get in touch with him (look at this bio on his qrz page) or DM me, I can connect you with him. 73 de VU2TUM.

Around the world are thousands of associations, groups of people, clubs if you like, that represent radio amateurs. Some of those associations are anointed with a special status, that of "member society" or "peak body", which allows them to represent their country with their own governments and on the international stage to the ITU, the International Telecommunications Union, through a global organisation, the IARU, the International Amateur Radio Union.

Some of these are known across our whole community, the ARRL in the USA, the RSGB in the UK, and the WIA in Australia. Some much less so, the CRAC, the Chinese Radio Amateurs Club, or the ARSI, the Amateur Radio Society of India, for example.

In an attempt to get a deeper understanding of what distinguishes these organisations, I visited a dozen member society websites. Cultural sensibilities and aesthetics aside, the variety and sense of priority is both pleasing and astounding.

Starting close to home, the WIA, the Wireless Institute of Australia, shows news as the most important and the top story is a radio contact between the International Space Station and a school, held about two weeks ago.

The ERAU, the Estonian Radio Amateurs Association, features an article about the 2025 General Meeting outlining who was there, what was discussed and thanking the participants for their contributions.

When I visited, the ARRL, the American Radio Relay League, top news item, was the renewed defence of the 902-928 MHz Amateur Radio Band, from a few days ago. The most important issue for the ARRL is that you read the latest edition of QST magazine, but only if you're a member.

The RSGB, the Radio Society of Great Britain, has an odd landing page that links to the main site, which features much of the same content. The latest news is "Mental Health Awareness Week" and encourages us to celebrate kindness in our community.

The DARC, the German Amateur Radio Club, has a page full of announcements and the top one was an article about current solar activity including a coronal hole and various solar flares.

The ERASD, the Egyptian Radio Amateurs Society for Development, uses qsl.net as its main website. It features many images with text, presumably in Arabic, that unfortunately I was not able to translate. Curiously the landing page features some English text that welcomes all interested to join. I confess that I love the juxtaposition between a Yaesu FT-2000 transceiver and the images of Tutankhamun and the pyramids.

The RAC, the Radio Amateurs of Canada, use their homepage to promote its purpose, and features many pictures of their bi-monthly magazine, which you can only read if you're a member, which is where many of the homepage links seem to go.

The RCA, the Radio Club of Argentina, is promoting the 2024-2025 Railway Marathon, including links to descriptions of what constitutes a Railway Activation, how to reserve your station, and upcoming and past activations. There's also a reminder to renew your license.

The ARSI, the Amateur Radio Society of India, has a very sparse landing page showing their mission and not much else. Clicking around gives you lots of information about the history, activities, awards and the like. Unfortunately, I wasn't able to find out how to become licensed in India. There's hardly any images.

In contrast, the URA, the Union of Radio Amateurs of Andorra, lands you on a page with contact details and not much else. Clicking through the site gives you lots of pictures of happy people and maps, lots of maps.

The KARL, the Korean Amateur Radio League, features an announcement with a link to the 24th Amateur Radio Direction Finding, from a week ago, but it requires a login to actually read it.

The JARL, the Japan Amateur Radio League, features an announcement to a form you can complete to join the "List of stations from which you do not wish to receive QSL cards."

The NZART, the New Zealand Association of Radio Transmitters, features a big button to latest news and clicking on it shows the "Jock White Field Day", which was held several months ago.

I wasn't able to see the CRAC, the Chinese Radio Amateurs Club, since the page didn't load for me. The "Wayback machine", also known as archive.org, from a capture a few days ago, showed a news item announcing the intent to organise the 1st Class C Amateur Radio Technical "something", I say "something" because I cannot actually load the article and see what it has to say. The event was scheduled for a month ago, the announcement was from several months ago.

Content aside, finding sites was interesting too, mind you, there's plenty of member associations that don't have any web presence at all. Is that by choice, or necessity?

The IARU list of member societies conflicts with the list of national organisations shown on Wikipedia. The IARU has about 160 entries, I say about, since the list isn't really formatted as much as it's congealed. Let's just say, perhaps a table for tabular data might be a novel approach. Wikipedia is slightly better formatted, it lists 93 national organisations.

As it happens, both include a link to the national organisation for China, which is either the Chinese Radio Sports Association, with apparently two different acronyms, either CRSAOA, or CRSA, or if you believe the IARU as a source, it's the one I mentioned earlier, the CRAC. I don't know which one is right, but at least we can assume that the IARU page was updated formally, rather than edited by someone on the internet. Regardless of which one is the "real" Chinese national amateur radio organisation, none of the websites loaded for me.

Let's move on. It's interesting that several non-English sites like Korea, Japan and Germany feature a button that allows their site to be translated into English. What's even more interesting is that the English version of the site is not in any way the same content. In many cases it appears to be information relevant to English visitors rather than a translation. One notable exception is Estonia, which allows a visitor to read their site in Estonian or English right out of the box.

Unsurprisingly, the ARRL website has no buttons for Spanish, even though that represents about 13 percent of the USA population, let alone any other language.

I'd encourage you to visit a few and see what you can learn about the other members of our community around the world.

My visits leave me with questions.

What do these organisations stand for? What do they do? Are they there for amateurs, for aspirant members, the general public, for regulators, for their members, for fund raising and advertising, or international visitors and tourism?

It seems to me that looking at just a few of these organisations reveals a great many things about how they understand their own role and how they deliver service and just how much money they have to play with to make that happen.

I'll leave you to ponder how effective they might be and what your role is in that endeavour.

I'm Onno VK6FLAB

cross-posted from: https://lemmy.radio/post/7413978

The WisMesh Board ONE offers solar support, expansion slot, and a compact design for Meshtastic users—all for $30. Find out how it compares to popular models in this hands-on review.

The world’s largest amateur radio convention returns to the Greene County Fair and Expo Center this weekend, with a slate of new and classic experiences for ham radio fans of all ages.

Hamvention brought over 35,000 amateur radio enthusiasts and over 700 volunteers to Xenia last May, and organizers have seen “equally exciting” ticket sales for 2025. For comparison, the population of the entire city of Xenia is only about 25,000.

cross-posted from: https://lemmy.sdf.org/post/34434940

We’re gonna be so fucked. Get ready for shittier experiences with internet providers and cell companies.

I'm stoked to have successfully received and decoded an SSTV signal from the ISS for the first time using my cheap Baofeng radio and QSSTV. Took a few tries, but luckily the ISS has been passing over my area several times per day over the last few days, so I've had several opportunities to try it.

Since becoming a licensed amateur in 2010, I have spent a good amount of time putting together my thoughts on a weekly basis about the hobby and the community surrounding amateur radio. As you might know, my interest is eclectic, some might say random, but by enlarge, I go where the unicorns appear.

Over a year ago I mentioned in passing a community called HamSCI. The label on the box is "Ham Radio Science Citizen Investigation", which gives you a sense of what this is all about. It was started by amateur radio scientists who study upper atmospheric and space physics.

More formally, the HamSCI mission is the "Continuation and extension of the amateur's proven ability to contribute to the advancement of the radio art."

If you visit the hamsci.org website, and you should, you'll discover dozens of universities and around 1,300 people, many of whom are licensed radio amateurs, who are asking questions and discovering answers that matter to more than just our amateur community.

For the eighth time the HamSCI community held an annual "workshop", really, an opportunity to get together and share ideas, in person and across the internet, a conference by any other name.

Under the banner theme of "HamSCI's Big Year", over two days, 56 people representing 27 different organisations across 61 sessions, tutorials, discussions, tours, posters and demonstrations, explored topics all over our hobby, from the Personal Space Weather Network, capable of making ground based measurements of the space environment, to the Whistler Catcher Pi, a project to record the VLF spectrum to 48 kHz using a Raspberry Pi.

You'll find research into HF antennas for the DASI or Distributed Array of Small Instruments project and associated NSF grants, exploring measurements of HF and VLF, combined with GPS and magnetometer across 20 to 30 stations.

There's discussions on how to explore Geospace Data, such as information coming from the Personal Space Weather Station network, or PSWS, using the OpenSpace project and dealing with the challenges of visualising across a wide scale, all the way up to the entire known universe. Did I mention that there's work underway to add PSWS compatible receivers to Antarctica?

There reports on observations and modelling of the ionospheric effects of the April 2024 solar eclipse QSO party, including Doppler radio, HF time differences, and Medium Wave signal enhancements, not to mention planning and promoting future meteor scatter QSO parties.

There's, post-sunset sporadic-F propagation, large scale travelling ionospheric disturbances, GPS disciplined beacons, the physical nature of sporadic-E propagation and plenty more.

As you might have heard me say at one time or another, the difference between fiddling and science is writing it down. It means that you'll find every session has accompanying documentation, charts, graphics and scientific papers. Remember, there's eight years of reading to catch up with, or learn from, or play with. The publications and presentations section on the hamsci.org website currently has 526 different entries.

You might not be interested in the impact of radio wave and GPS scintillation, or rapid fluctuation in strength, caused during the G5 geomagnetic storm that occurred on the 10th of May 2024, or a statistical study of ion temperature anistropy using AMISR, or Advanced Modular Incoherent Scatter Radar data .. or you might.

In case you're curious, "anistropy" is the property of being directionally dependent, in other words, it matters in which direction you measure, which might have some relevance to you if you consider that we think of the ionosphere and radio paths being reciprocal. If it reminds you of isotropy, that's because they're opposites.

The point being, that amateur radio is a great many things to different people. If you're a scientist, budding, graduate or tenured, there's a home for you within this amazing hobby.

I'm Onno VK6FLAB

tl;dr: if you could build a tiny array of nantennas, could you use it to form an image?

My inspiration for this idea comes from insect compound eyes as well as some uses of optical fiber like boroscopes and endoscopes, where light enters a dense array of optical fibers and emerges as an image on the other end.

The idea is that you have a densely packed array of nanoscopic antennas that are resonant at visible wavelengths, with each antenna connected to its own "feed line" which all in turn connect to a receiver that can collate the received signals from all the antennas into an image.

The ISS is currently transmitting SSTV pictures on 145.800 MHz using the PD120 mode.

"Impedance matching is one of the perpetual confusions for new electronics students, and for good reason: the idea that increasing the impedance of a circuit can lead to more power transmission is frighteningly unintuitive at first glance. Even once you understand this, designing a circuit with impedance matching is a tricky task, and it’s here that [Ralph Gable]’s introduction to impedance matching is helpful."

Cross posted from https://rss.ponder.cat/post/172998

Recently I saw a social media post featuring a screenshot of some random website with pretty charts and indicators describing "current HF propagation". Aside from lacking a date, it helpfully included notations like "Solar Storm Imminent" and "Band Closed".

It made me wonder, not for the first time, what the reliability of this type of notification is. Does it actually indicate what you might expect when you get on air to make noise, is it globally relevant, is the data valid or real-time? You get the idea.

How do you determine the relationship between this pretty display and reality?

Immediately the WSPR or Weak Signal Propagation Reporter database came to mind. It's a massive collection of signal reports capturing time, band, station and other parameters, one of which is the Signal To Noise ratio or SNR.

If the number of sun spots, or a geomagnetic index change affected propagation, can we see an effect on the SNR?

Although there's close on a million records per day, I'll note in advance that my current approach of taking a daily average across all reports on a specific band, completely ignores the number of reports, the types and direction of antennas, the distance between stations, transmitter power, local noise or any number of other variables.

Using the online "wspr.live" database, looking only at 2024, I linked the daily recorded WSPR SNR average per band to the Sun Spot Numbers and Geomagnetic Index and immediately ran into problems. For starters the daily Sun Spot Number or SSN, from the Royal Observatory in Belgium does not appear to be complete. I'm not yet sure why.

For example, there's only 288 days of SSN data in 2024. Does this mean that the observers were on holiday on the other 78 days, or was the SSN zero? Curiously there's 60 days where there's more than one recording and as a bonus, on New Years Eve 2024, there's three recordings, all with the same time stamp, midnight, with 181, 194 and 194 sun spots, so I took the daily average. Also, I ignored the timezone, since that's not apparent.

Similarly the Geomagnetic Index data from the Helmholtz Centre for Geosciences in Potsdam, Germany has several weird artefacts around 1970's data, but fortunately not within 2024 that I saw. The data is collected every three hours, so I averaged that, too.

After excluding days where the SSN was missing, I ran into the next issue, my database query was too big, understandable, since there are many reports in this database, 2 billion, give or take, for 2024 alone.

Normally I'd be running this type of query on my own hardware, but you might know that I lost my main research computer last year, well, I didn't lose it as such, I can see it from where I am right now, but it won't power up. Money aside, I've been working on it, but being unceremoniously moved from Intel to ARM is not something I'd recommend.

I created a script that extracted the data, one day at a time, with 30 seconds between each query. Three hours later I had preliminary numbers.

The result was 6,239 records across 116 bands, which of course should immediately spark interest, since we don't really have that many bands. I sorted the output by the number of reports per band and discovered that the maximum number of days per band was 276. This in turn should surprise you, since there's 365 days in a year, well technically a smidge more, but for now, 365 is fine, not to mention that 2024 was a leap-year.

So, what happened to the other 90 days? We know that 78 are missing because the SSN wasn't in the database but the other 12 days? I'm going to ignore that too.

I removed all the bands that had less than 276 reports per day, leaving 17 bands, including the well known 13 MHz band, the what, yeah, there's a few others like that.

I removed the obvious weird band, but what's the 430 MHz band, when the 70cm band in WSPR is defined as 432 MHz?

I manually created 15 charts plotting dates against SNR, SSN, Kp and ap indices. Remember, this is a daily average of each of these, just to get a handle on what I'm looking at.

Immediately several things become apparent. There are plenty of bands where the relationship between the average SNR and the other influences appear to be negligible.

We can see the average SNR move up and down across the year, following the seasons - which raises a specific question. If the SNR is averaged across the whole planet from all WSPR stations, why are we seeing seasonal variation, given that while it's Winter here in VK, it's Summer on the other side of the equator?

If you compare the maximum average SNR of a band against the minimum average SNR of the same band, you can get a sense of how much the sun spots and geomagnetic index influences the planet as a whole on that band. The band with the least amount of variation is the 30m band.

Said differently, with all the changes going on around propagation, the 30m band appears to be the most stable, followed by the 12m and 15m bands. The SNR across all of HF varies, on average, no more than 5 dB.

The higher the band, the more variation there is. Of course it's also possible that there's less reports there, so we might be seeing the impact of individual station variables more keenly.

It's too early for conclusions, but I can tell you that this gives us plenty of new questions to ask.

I'm Onno VK6FLAB

If you are not familiar with POCSAG or its usage check out [https://en.wikipedia.org/wiki/DAPNET](Decentralised Amateur Paging Network) .

This is a little write up on how to use SDRangel and multimon-ng to decode multiple parallel POCSAG signals with only one RTL SDR stick.

This happens in a Linux environment, not sure if this will work on windows.

1. Install SDRangle, multimon-gn and sox
2. Open SDRangle and select your SDR as source.
3. Select your desired Frequency and find your POCSAG signals using the waterfall display
4. Activate AGC

If you want to listen to the signal only without decoding:

• Press the add channel button and Select "NFM Demodulator"

If you want to decode the POCSAG using SDRangel's internal Demodulator:

• Press the add channel button and Select "Pager Demodulator"

SDRangel's internal Demodulator works, but it only decodes 512 or 1200 or 2400 baud POCSAG. Meaning if you have 3 frequency's, each carrying 521 and 1200 baud signals, you would need 6 decoding windows in your SDRangel's work environment.

But there is a more easy way to do this, multimon-ng.

How to use SDRangel with multimon-ng:

• Press the add channel button and Select "UDP sample sink"
• In the UDP window, center the desired frequency
• Set the settings:

This will generate a UDP stream on port 7355 for multimon-ng to decode.

To decode open a terminal and use this chain of commands:

nc -l -u -p 7355 | sox -t raw -esigned-integer -b 16 -r 48000 - -esigned-integer -b 16 -r 22050 -t raw - | multimon-ng -t raw -a POCSAG512 -a POCSAG1200 -a POCSAG2400 - | tee freqlog_1.txt

This is what it does: "nc -l -u -p 7355" pipes in the UDP sound frames, "sox" converts the input to something usable for multimon-ng, "multimon-ng" attempts decoding and puts out text "tee" display the outputs in the terminal while also logging to a text file

To decode multiple signals in parallel, open another UDP Sample sink window with the same settings but change the port to 7356, then again center your desired frequency.

Open another terminal and repeat the command chain, but replace 7355 with 7356 and increase the number in the log file name by one.

You can do this with as many signals as you want, as long as they are in the same Bandwidth your SDR is set, for a cheap SDR stick you may watch everthing that happents in a 2Mhz window, with a better one you can do 20Mhz or more.

Now you should have open multiple terminals, each logging its own frequency, but how to pipe that into one terminal so you dont have to switch?

tail -f freqlog_1.txt freqlog_2.txt freqlog_3.txt

This watches for changes in the end of the log files and pipes it all in one terminal.

Thats it for my write up, now have fun decoding.

Ever wondered if you could send voice notes over Meshtastic's low-bandwidth network? I certainly did, and I'm excited to share my weekend adventure trying to accomplish just that.

I did a thing, and it even worked. Probably mechanically the simplest way to make antenna with gain over dipole is to use two 5/8 lambda elements, but really anything longer than 1/4 lambda already gives improvement, 5/8 is just maximum. No coils or other delaying elements within radiating part of antenna are needed, with disadvantage that impedance is complex. Normally, this is dealt with by putting coils at the base, but there are other options.

Some variants of single stub tuning appear in J-poles and beta/hairpin matches. In general, it only takes single transmission line and two variable positions of shorting bar and feedpoint, and it can match any impedance at single frequency, given appropriate choice of that transmission line impedance. I've picked 240 ohm - lowest I could get away with - and it wouldn't allow to match normal 5/4 lambda antenna, so I shortened it instead to 1.1 lambda - this gives higher initial impedance that is easier to match this way. (Sometimes I could find impedance of this antenna given as 150-850j, but this is just twice impedance of 5/8 lambda monopole, assumed to be thin. Analytical formula on wiki page gives for 5/4 lambda, 5mm wide dipole for 435MHz 214-330j, maximum usable transmission line impedance would be closer to 200 ohm then. Actual simulation like in NEC would be more trustworthy)

Construction wise, this is rather simple device. I've used two pieces of 5mm aluminum wire for dipole and matching section, and connecting blocks cut in half and soldered on the bottom side for connections to shorting bar and feedpoint. This allows for easy moving of both and relatively effortless matching

I'm pretty sure that balun like this is proper overkill, but I wanted to make sure that common mode currents don't mess my measurements. Tuning turns out to be pretty straightforward, with feedpoint position having bigger influence on SWR than shorting bar position. End result is rather wideband, with SWR just 1:1.2 on edges of 70 cm band:

Being 1.1 lambda long (80cm on 70cm band), this antenna is probably suitable for VHF-UHF only. On lower side, radiator length starts to be unwieldy (6.5m on 6m band, 2.3m on 2m band), on higher end, matching section would become tiny. The latter limitation can be probably solved with use of PCB traces forming both radiating element and matching section (board size approx 15x5cm should be sufficient for 13cm band - two sides and at least one via needed), which would also allow for lower impedances of transmission line, therefore getting closer to 5/4 lambda length. (This would probably require considerable number of simulations and prototyping, both beyond my abilities right now). On lower VHF, perhaps 70mm or similar drainage pipe could be better waterproof housing for matching section, especially if balun can be skipped and if matching section turns out to be long. Wires can be probably extended beyond shorting bar and used for support, like it is sometimes done with J-poles.

Any criticism, advice, good practices, tips, etc welcome

Some tools used https://hamwaves.com/zc.circular/en/index.html https://www.will-kelsey.com/smith_chart/

A recent comment by a fellow amateur sparked a train of thought that made me wonder why there is a pervasive idea within our community that you need a radio transmitter and antenna to be a radio amateur, moreover that for some reason, if you don't have either, you're not a real amateur.

I suppose it's related to the often repeated trope that the internet enabled modes like Allstar Link, Echolink and even IRLP, are not real radio, despite evidence to the contrary.

Instead of fighting this weird notion, I figured I'd get on with it and find a way to play even if you don't currently have the ability to erect an antenna or key a transmitter for whatever reason.

Before I dig in, a WebSDR is a Software Defined Radio connected to the Internet. It allows a user to open a web browser, pick from a massive collection of receivers around the world and listen in. Some of these also have the ability to transmit, but more on that later.

Here's the idea.

Have you ever considered tuning to a WebSDR, using it to pick a signal and using your computer to decode that signal? I'm aware that some sites provide a range of in-built decoders, but that doesn't cover the wide spectrum of modes that amateur radio represents, let alone the modes that are not specific to our hobby.

As I've said previously, many of the modes in use today are essentially the width of an audio stream. This means that if you tune a WebSDR to a frequency the audio comes out of your computer speakers. If that's voice, your job is done and you can hear what's going on. If it's something else, then you're going to have to find a way to decode this to get the message.

So, if you send the audio from your web browser into something like Fldigi or WSJT-X, you'll be able to decode the signal if it's supported by those tools. This is true for all the other tools too, Morse, RTTY, you name it.

Depending on which operating system you're using the way to implement this will differ. Starting with a search for "WebSDR and WSJT-X" will get you on your way. You might ask why I'm advocating WSJT-X, even though it only supports a small set of modes and that's a fair question. In my experience, it's the simplest to get running and get results. Two tips, make sure you set your configuration to indicate that you don't have a radio, otherwise it's going to attempt to control something that isn't there, and make sure that your computer clock is set accurately using NTP or Network Time Protocol. You can thank me later.

Now I hinted earlier at transmitting. There's a growing range of places where your amateur license will give you access to a station somewhere on the internet and with that the ability to get on air and make noise. An increasing number of radio amateur clubs are building remote stations for their members to enjoy. There are also individuals and small groups doing the same independently. A few organisations are offering this as a service to paid subscribers.

These tools often implement a remote desktop session where you connect to a computer that in turn is connected to a radio. The supported modes depend on what is installed at the other end. Others implement a slightly different method where you run specialised software locally, sometimes inside a web browser, that connects to a server across the internet, allowing you to run whatever digital mode you want on your own computer.

I'll point out that even if you start with receiving digital modes using a WebSDR, you can expand that into transmitting at a later stage.

So, no antenna, no transmitter, no problem, still an amateur!

I'm Onno VK6FLAB

Right: 10nF made from Aluminum foil and Mylar emergency blanket

Left: 5nF made from Copper tape and masking tape