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Foundations of Amateur Radio

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Starting in the wonderful hobby of Amateur or HAM Radio can be daunting and challenging but can be very rewarding. Every week I look at a different aspect of the hobby, how you might fit in and get the very best from the 1000 hobbies that Amateur Radio represents. Note that this podcast started in 2011 as "What use is an F-call?".

Location:

United States

Description:

Starting in the wonderful hobby of Amateur or HAM Radio can be daunting and challenging but can be very rewarding. Every week I look at a different aspect of the hobby, how you might fit in and get the very best from the 1000 hobbies that Amateur Radio represents. Note that this podcast started in 2011 as "What use is an F-call?".

Twitter:

@vk6flab

Language:

English


Episodes
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Decoding a signal ...

7/12/2025
Foundations of Amateur Radio Recently I was given some radio data captured on the 40m band. Using a piece of software called "Universal Radio Hacker", I attempted to decode it. At the time I thought that this might be Morse code, since then I've been told by someone who has been using Morse longer than I've been alive, that it isn't. I shared the data on my VK6FLAB GitHub repository where you can download it and see what you learn, and perhaps repeat what I did, or better still, improve on it. Over the years I've talked a little about how Software Defined Radio or SDR works, essentially it's a glorified Analogue to Digital converter, much like the sound card in your computer, which does the same, albeit at a much lower frequency. As it happens, you can represent the signal that comes into your radio antenna as a series of values. Essentially, the stronger the signal, the bigger the number, the weaker the signal, the lower the number. Let's talk about the characteristics of this signal. It consists of two parallel signals, in opposition to each other. The first signal jumps intermittently between 7 kHz and 40 kHz, where the second jumps between -7 kHz and -40 kHz. The recording is marked 7.06 MHz, so if we think of that as the central frequency, the whole signal sits between 7.02 and 7.1 MHz. This 80 kHz wide signal is not something you'd typically be able to hear using a standard amateur radio receiver which tops out at about 3 kHz bandwidth. It's so wide that you couldn't even hear more than one of the four tones at the same time. Randall VK6WR, who supplied the recording, spotted it on a waterfall display showing a chunk of radio spectrum, in fact, a $25 RTL-SDR dongle could receive this signal. Aside from the fact that this is a really wide signal, well at least in traditional amateur radio terms, it was interesting in that it was heard on the 40m band. As it happens, just after I shared my initial exploration, I was told by several other amateurs that they had heard the signal. I even saw it on a WebSDR in India and attempted to record it, but failed. As it happens, a few weeks ago, I was playing with something called "CAN Bus", or Controller Area Network, a technology that was designed in 1983 and is used all over cars for things like sensors for speed, engine temperature, oxygen level, detonation timing and anything else that's happening inside a car. You might know the end-user view of this called OBD2 or On Board Diagnostics, second generation. I was looking into it because my car has been acting up and I've been trying to track down the root cause. Anyway, I learned that CAN Bus is implemented using something neat, "differential signalling", where two wires each carry the same, but opposite signal, so they can be combined to ensure that in an electrically noisy environment like a car, the information still gets where it needs to go. Seeing the radio signal Randall shared, reminded me of this. Noise immunity is a useful attribute in digital HF communication, so I can understand why it was done like this, but it also means that either signal was sufficient to start to decode the information. We can use Universal Radio Hacker to show us only half the signal using a band pass filter. I then decided that the 40 kHz frequency was "on" and represented by a "one" and the 7 kHz frequency was "off", represented by a "zero". Of course that's entirely arbitrary, there's no reason that it cannot be the other way around, but for our purposes it doesn't matter at this time. That said, we don't yet have enough to decode the actual signal. We need to figure out how long each switch, or bit, lasts, because two zero's side-by-side or two ones side-by-side would look like a long "off" or a long "on". Using that logic, you could also say that the shortest possible duration for a 40 kHz or a 7 kHz tone would represent a single "one" or a single "zero". Of course, this is a simplified view of the world. For example, the data...

Duration:00:08:22

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Antenna modelling with genetic algorithms.

7/5/2025
Foundations of Amateur Radio Recently I was helping a friend erect their newly refurbished multi-band antenna and during the process we discussed the notion of tuning an antenna that's high in the air. They made a curious response, in that they'd tuned the antenna on the ground before we started. I asked how this would work, since as I understand the process, this changes things once it gets in the air. They assured me that while the actual SWR might change, the frequencies at which it was resonant would not. This was news to me because I've been putting off erecting my own multi-band 6BTV antenna mainly because I didn't really want to face having to erect it, tune it, lower it, modify the elements, erect it, tune it, etc., all whilst standing on the steel roof of my patio. Would this phenomenon be true for my antenna? It occurred to me that I could test this idea, not only for my antenna, but for other antennas as well. In my minds-eye, I saw a video displaying the pertinent attributes of an antenna, SWR, gain, radiation pattern, and whatever else I could think of, animated with the modifications of things like height and ground radials. If this sounds familiar in some way, it's because I've been here before. This time the outcome was slightly different, since I found a tool that can optimise antennas using a genetic algorithm. What I mean by that is an automated process where you can test variations of a thing, in this case antennas. Rather than design each antenna and test it, you essentially generate antenna designs and tweak them to determine the best one. Then you use that to generate the next series of designs. Rinse and repeat until you have what you're looking for. There's a whole field of computer science dedicated to this and unsurprisingly the rabbit hole goes deep. The tool is called "xnec2c-gao" and it's written by Maurizio DC1MDP. The name of the tool hints at its nature, working in combination with "xnec2c", written by Neoklis 5B4AZ and maintained by Eric KJ7LNW, you'll find links to both tools on the xnec2c.org website. How the two tools work together is a beautiful dance. The antenna modelling tool, xnec2c, can read an antenna definition file and detect if it changes, at which point it can redo the simulation, which it can output to another file. The genetic algorithm optimisation tool, xnec2c-gao, can detect the changed output and update the antenna definition file, and the process repeats. Which brings me to a pro-tip, for this to work, you need to configure xnec2c to do two things, detect the changed definition file, and write the output to CSV, both of these options can be found in the "Optimization Settings" menu, just so you don't spend an hour banging your head against the desk. Between the two tools, the antenna definition evolves and you end up with a design optimised for your purpose. The default does this for SWR and gain. Mind you, I tested a multi-band dipole which managed to find some interesting designs, but didn't pick them because a low SWR combined with a high gain, for reason't I don't yet understand, wasn't considered better than a high SWR with a high gain, so there's some work to be done. As a software developer I have a sneaking suspicion that it's adding the two, rather than picking the highest gain combined with the lowest SWR, but I haven't confirmed that. As I said, deep rabbit hole. While we're not yet at the video display stage, for the first time I can get a sense that this might come to pass. There's plenty of work to be done. For example, the antenna display on xnec2c during the process seems broken, there's no way to output gnuplot files during the process, and capturing the various charts in real-time will require work, but all that seems if not easy, at least possible. Meanwhile, I'm attempting to locate an antenna definition file, preferably in .NEC format for my 6BTV antenna, so I can use this combination of tools to discover if tuning it on the ground will work...

Duration:00:05:08

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The ARRL incident of May 2024, a year later

6/28/2025
Foundations of Amateur Radio Just over a year ago, the ARRL, the American Radio Relay League, the peak body for amateur radio in the United States and one of the oldest of such organisations, experienced an incident. During the weeks following, the ARRL was tight-lipped about the extent of the incident and most amateurs only really noticed that services were off-line or slow to respond. After months of delay and disinformation, the ARRL finally revealed that it was the subject of a ransomware attack and that it had paid a million dollar ransom. It went on to blame the authorities for its silence. Mind you, it didn't tell me personally, it made public statements on its website. Similarly when I specifically contacted the ARRL to discover what information of mine it held, and what the status of that information was, the ARRL responded that I should refer to its public statements. It continued to state that my information was not compromised, since it only lived in LoTW, the Logbook of The World, the system it uses to coordinate the verification of amateur radio contacts, which are used to distribute awards like the DXCC and Worked All whatever. Imagine my surprise when I received an email this week, sent from "memberlist@arrl.org" to my non-amateur radio email address. I confirmed with several amateurs that they too received this email. Informative, to a point, but likely well beyond anything intended by its author, it stated that LoTW was being updated with associated down time, incidentally, inexplicably, coinciding with the 2025 ARRL Field day, and it "will be fully migrated to the cloud". It went on to solicit donations. It made no reference whatsoever to the ransomware attack. There's a lot hidden in that email. Although the attack last year was linked to the outage associated with LoTW, the ARRL has continued to claim that the LoTW data was not impacted by the ransomware attack, but the email reveals that the system is being migrated to the cloud, in other words, right now, it's not in the cloud. Which begs the question, where is the server infrastructure for LoTW today, and more importantly, where was it a year ago when its systems were compromised? From a public post by Dave AA6YQ, dated the 2nd of February 2021, in response to a message about a January LoTW committee meeting, we know that the LoTW server "now employs the current version of an SAP database engine". A month before that, Dave wrote another informative email that indicated that 105 thousand callsigns submitted logs to LoTW in the last 1,826 days or the five years between 2016 and 2021. There were logs from 21 thousand callsigns in the week prior to that January post. In all, according to Dave, there were 153,246 callsigns who submitted contacts to LoTW. The LoTW committee meeting minutes are no longer available from the ARRL website, but I have a copy. The document states that there were 1.2 billion contacts entered into LoTW, big number right? The next line tells us that this resulted in 262 million QSO records. I wonder what happened to the other billion records? This activity was generated by 139 thousand users using 200 thousand certificates. For context, every VK callsign automatically comes with an AX callsign, but LoTW requires that you separately register each with its own certificate. As someone who has been playing with databases since the 1980's I can tell you that LoTW is a tiny database. For comparison, the WSPR database is an order of magnitude larger, not to mention, more active. I have no insight into the business rules within the LoTW database, but the fact that updates are being processed in batches and that it regularly has delays indicates a level of complexity that I cannot account for. As an aside, the LoTW committee document lists 10 members. Dave is not one of those listed. It makes me wonder who else has access to this database. Note that I have no reason to believe that Dave's information is questionable, nor that he has...

Duration:00:12:27

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The Art of decoding a signal.

6/21/2025
Foundations of Amateur Radio The other day Randall, VK6WR, encouraged me to get on-air. He described it like this: "There is a mystery signal on 40m that you can try your new Universal Radio Hacker skills on. It appears to be a FSK signal separated by 7kHz with the two signals at 7.0615 and 7.0685 MHz. Each of them on their own sounds a bit like a Morse signal, but my CW decoder decodes junk. But if you can see it on a spectrum scope, it is clearly FSK because either one of them is on at any time." He went on to say: "You'll need an SDR to receive the signal given the separation, but could be a fun investigation!" Having just discovered "Universal Radio Hacker", a tool that can help you decode radio signals, that sounded like something I'd love to have a go at. Unfortunately, after the demise of my main workstation last year, my current set-up doesn't allow me to do such recordings, but Randall, ever the gentleman, provided a recording of the signal. He writes: "This was captured with gqrx demodulating the signal as SSB audio with the VFO tuned to 7.060, so both "signals" are there, one very low freq and one very high freq." If you're curious, I've uploaded the file as it was shared with me to my VK6FLAB GitHub repository under "signals". Over the next two days I spent my time attempting to decode this signal. I opened up Universal Radio Hacker and spent delightful hours getting precisely .. nowhere. Some of that is absolutely my unfamiliarity with the tool, but this is a great exercise in learning on the fly, where truth be told, I tend to live most of my life. It wasn't until several hours later that I decided I should at least listen to the audio. To my ear it sounded like 25 WPM Morse Code, but being still in the learning phases, while my brain was triggering on the sequences, decoding wasn't happening. Of course I could cheat and forward the audio to one of my fellow amateurs, but the actual message wasn't really the point of the exercise, at least not at this stage. Instead I fired up "multimon-ng" which has an in-built Morse decoder. I spent some hours doing more Yak Shaving than I was expecting, but even then, I still didn't get more than gobbledegook out of the process. I used "Audacity" to shift one of the signals by one wavelength and mixed them together. This allowed me to reduce the noise significantly, but still none of my tools did anything useful. In case you're wondering why, if you have a tone and noise and shift one signal by the wavelength of the tone, then mix them, the tone adds to itself, but the noise, random in nature, is just as likely to add as it is to subtract, so in effect, you're increased the signal to noise ratio. After multimon-ng failed, I tried an online Morse decoder, which gave me all manner of text, but none of it made sense to me. Of course it's possible that this is someone rag chewing in a different language, but I couldn't make any sense of the thing. I did come up with some issues that prompted me to create the signal repository. I realised that I didn't have any known "good" signals. Previously I'd tried decoding a sample FT4 signal, but that went nowhere, mainly because the signal was noisy. So, what I'm going to do over the next couple of weeks is create some clean, as-in, computer generated, known signals, and add them to the repository. The aim is to have a known good starting point to learn from. In software development this technique is often used to limit the number of unconstrained variables. In our case, if I generate a known good Morse Code signal, then I can learn how to use Universal Radio Hacker to decode it, so when I come across an unknown signal, I can use the techniques I learnt to attempt to decode it. Feel free to make pull requests with known good signals yourself. RTTY, PSK31, WSPR, FT8, etc. Feel free to include non-amateur modes. One thing, I'm not looking for off-air recordings of signals, yet, that can come later, right now I need signals that...

Duration:00:05:10

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Random Serendipity

6/14/2025
Foundations of Amateur Radio The other day I was discussing with a fellow amateur the increased frustration my mobile phone provider was inflicting. We hit on the idea of figuring out if other providers would fit the bill and how we could determine if their coverage would suit our needs. Aside from using an old mobile phone, I suggested that using a $25 RTL-SDR dongle would provide a way to record mobile phone cell site beacons from the various mobile networks to map what signal levels we might find. To that end, I discovered a tool called LTE-Cell-Scanner by Xianjun BH1RXH. Forked from the original project by James Peroulas, it allows you to use simple hardware to scan for LTE Cells used by mobile phone networks. James points out on his site that this tool can also be used to calibrate an RTL-SDR receiver's oscillator, since an LTE downlink centre frequency is stable to within 50 Parts Per Billion, that's 10 times more stable than my Yaesu FT-857d using a TCXO. If this doesn't mean much, think of it as a local frequency reference standard that you can use in your shack with minimal effort and cost. The story gets better. I started building LTE-Cell-Scanner from source and in doing so discovered a directory on my computer named "uhrr". I didn't remember what it was for, so I looked online. The first search result, when I looked for "uhrr radio" was a repository by Oliver F4HTB, more on that in a bit. The second search result was something called "Universal Radio Hacker". I clicked on the link and discovered a mind boggling tool. There are times in your life when something flips, this was one of those times. It happened when I discovered "csdr" by Andras HA7ILM and again when I discovered "GNU Radio". Diving into "Universal Radio Hacker", by Dr. Johannes Pohl and Dr. Andreas Noack I was introduced to the art of decoding and generating digital radio signals. In 2018 it was presented for the first time during the USENIX Workshop on Offensive Technologies, or WOOT, as a tool to discover, decode and identify exploits of proprietary IoT devices scattered all over the planet. As an aside, USENIX, Users Of Unix, since 1975. Back to radio. Universal Radio Hacker allows you to dissect recorded radio signals using all manner of interactive processes. When you go looking for it, and you should, I recommend that you start by watching some videos. You'll find an introductory play list on my YouTube channel. By the time you've seen those, you'll likely share my excitement. To encourage you further, the Universal Radio Hacker is open source, written in Python, and runs on Linux, MacOS and Windows. So far there have been 94 releases of the software, so it's seen significant development in the years since it was released into the wild. When installing it I was surprised to discover that its acronym was "uhr", not "uhrr". This was a relief since I still didn't remember what "uhrr" was all about and I couldn't imagine having forgotten Universal Radio Hacker. It turns out that the last time I looked at "uhrr" was apparently in 2021 when I shared my experience in an article titled "The remote edge..."; "uhrr" or "Universal Ham Radio Remote" is a tool that allows you to use a web browser to access a radio remotely. My little journey into unexpected diversions, distractions and discovery has led me into a path where several puzzle pieces have come together. For example, Universal Radio Hacker and GNU Radio can talk to each other, they're both written in Python, they're both open source, have a history of development and have a community of users. The LTE-Cell-Scanner, also open source, will allow me to calibrate most if not all of my radio gear and I'm once again inspired to keep digging into yet another aspect of this wonderful hobby. I'm sure that there are more than a thousand different hobbies under this roof. Go forth, explore, discover, be amazed, and stay curious! I'm Onno VK6FLAB

Duration:00:05:02

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Can you be a Professional Radio Amateur?

6/7/2025
Foundations of Amateur Radio The other day a fellow amateur asked me to help them with lowering their radio mast so they could do some maintenance on the antennas attached to it. This is not the first time I've been a participant in such an activity, but it was the first time I felt explicitly safe. Don't get me wrong, on previous occasions nothing bad happened, but there was always an undertone of "what-if" and an associated anxiety. This time was different. Before we did anything, we sat down, had a cup of coffee, talked and discussed what was going to happen. After coffee we looked at specifics and discussed the process in detail. Then we prepared. Clipping cable ties, winding up loose ends, disconnecting coax, and securing a pulley to a tree. We ran a winch line, discussed distances, looked at potential snags and coax lengths and angles, considered what would happen if something unexpected might happen and discussed various safety considerations, like never walking below the mast whilst it was in its most stressed position, half-way lowered and out of reach. Then we slowly went about doing what we talked about. All that sounds pretty reasonable, and it should. It was the first time I'd ever discussed in detail what the plan was, what could happen if something broke, if something got caught and any number of contingencies. We even discussed handling steel winch lines, something which I was unfamiliar with. Of course it's entirely possible that something bad could happen, something neither of us had considered, but we put ourselves in a position where we both felt safe after mitigating known risks and allowing leeway for unknown risks. Another word for this type of preparation is "Professionalism". It's a fraught word. You might recall me telling a story where I contacted the regulator to discuss wideband interference caused by a train-line, specifically blocking out a range of AM broadcast frequencies, including the emergency broadcast station. I revealed during that conversation that I was an amateur and had some experience with radio. The person I was speaking to shared that they were a "Professional", using a capital "P" to condescend that my amateur credentials were nothing in comparison to theirs. The conversation ended, the wideband interference is still there, years later. It's not the only time I've come across this weird relationship with this word "Professionalism". At one time I worked at a community broadcaster where I was one of the producers and presenters. If you're unfamiliar, it's essentially a special interest broadcaster, in this case radio, run by mostly volunteers. We were having a meeting to discuss plans and during that I raised the notion of "Professionalism" in relation to conduct, things like turning up on time for your shift, documenting labels correctly on tapes, keeping logs, broadcasting advertisements at the allocated time, etc. Unfortunately some in the group equated "Professionalism" with "Commercialism" and expressed their discontent with the notion vocally. I stopped volunteering there shortly after. This to say that I can understand that "Professionalism" has different meanings for different people. In a community like Amateur Radio it might mean that it's considered a taboo word, but I'd like to encourage you to think of it as a way of getting things done .. safely .. and to the betterment of the community. So, next time you have a working bee, an antenna party, a contest, or a ham-fest, think about how you conduct yourself, how you might improve the experience for yourself and for those around you. I call that "Professionalism". I'm Onno VK6FLAB

Duration:00:03:56

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What's really happening at the IARU?

5/31/2025
Foundations of Amateur Radio The other day a report in "Amateur Radio Daily" caught my eye. Under the heading "IARU Considers Consolidation", I read that the International Amateur Radio Union, celebrating 100 years of representing our hobby, is considering significant change. Links in the report reveal a PDF document titled "IARU Consultation on Proposed Restructuring March 2025". The document, dated 21 March, outlines the structure of the IARU, four organisations, one for each ITU Region, and one global organisation, the International Secretariat. It provides some insights on how the funding arrangements between these organisations exist and goes on to talk about how the IARU operates, including incorporation, or not, currencies, committees, priorities and other background and historic information. All excellent. Stuff that should be public knowledge, but having spent the better part of a year reading IARU documents, this one brought several new eye opening things to the table. The document attributes no authors but is at least spell-checked in US English, and appears to be part of a discussion started long before I became an amateur. In 2005, the IARU started the "IARU 2025 Committee" to look into the future of the organisation. It concluded its work in 2012. In 2020 a new committee was started, the "Future Committee", consisting of representation from each of the regions. The introductory wording is curious and includes these words: "We can no longer afford not to move the process forward" - at least implying that this document is a foregone conclusion. Searching for the document on the IARU sites will give you no results. Searching for "Future Committee", gives you two results, neither actually having the words "Future Committee". The only reference which makes any sense in either of those two results, and only after the fact, is a paragraph, published on 12 October 2020, that refers to the Administrative Council, or AC, and states: "The AC received and discussed an in-depth report from its Working Group on the Future of IARU and agreed to steps for evolving toward a more flexible organization and strengthened relationships with all stakeholders in the global amateur radio community and telecommunications ecosystem." For a process that started 20 years ago, this is the first I've heard of it. Curious wouldn't you say, in an organisation that claims to represent both you and I? It's almost like the IARU wants to keep this whole thing a secret. There's more. The thrust of the document is to explore the notion of simplifying the operation of the IARU by consolidating the four organisations into one incorporated body based in Switzerland, where the IARU Region 1 organisation is currently incorporated. It goes on to discuss how this is great for the hobby, how it will save on resources and how it will allow the mostly volunteer run organisation to operate more democratically. It outlines the process for adoption, including a 60 day consultation period for the 167 Member Societies, as-in peak bodies in your country. I'll save you the suspense, the consultation period ended before I saw the document. There's a 30 day "Detailed Draft Proposal phase" and a "Final Proposal and Voting stage", neither of which are on any specific time-line that I could find. You might say, well, Onno, you're not a member society, it's none of your business. That's true. Here's the thing. Let me quote from Section 5, on page 11: "In many cases the IARU Member-Society does not represent the majority of the national amateur community." So .. not to belabour the point, the IARU, who is proud to represent Amateur Radio on the International Stage, writes in its own documentation that the organisation doesn't represent the majority of amateurs while claiming its intention to make the organisation more flexible and democratic. Gotta say, feeling all warm and fuzzy. In Section 6, the document goes into great detail about finance. I'm kidding, it...

Duration:00:09:49

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What do you think you're doing?

5/24/2025
Foundations of Amateur Radio Right off the bat, let me start with a question. "What do you think you're doing?" To give you some context, it should come as no surprise that I'm talking about amateur radio and what it is that we do, you and I, when we "do amateur radio". Of course the answer is different for every person you ask, and it's likely to change over time. So, let's explore and fair warning, if you know me at all, you'll realise that I'll be asking more questions, so here goes. Is this an activity that you do, for yourself, or for others? Is it a hobby, or a vocation, or something else? Do you use this as part of your life outside this community and if you do, how? At this point I hope you're getting a sense of Deja-Vu all over again, in that I'm asking you to explore your own place in the community. I'm asking because it occurs to me that we spend an awful lot of time looking in the other direction. How do we compare skills and knowledge against other amateurs, how does our shack compare with another, how does our antenna stack up, which modes have you used, what things have you activated, how much power do you use? All things that might form part of the activity of amateur radio, but fail to look at you as a person and your role in this. For example, have you considered if you're interested in helping new amateurs, or would you rather just do your own thing? What about how you gain skills? Would you rather read a book, watch a YouTube video, attend a class or play with others? If you're considering upgrading your license to gain more responsibilities, are you doing that for yourself, or are you doing it because of peer pressure? If you've been part of the hobby for a little while you'll have discovered that radio amateurs are everywhere, often in unexpected places. With that comes the realisation that this implies that we have members who represent all of humanity in all its many-splendored complexity. Where in that spectrum are you and what is your role in participating in that wider community, and is your role what you want it to be? One of the themes I've discovered over the years is insecurity. A recurring perception is that amateurs who've attained the highest license level are somehow "more" amateur than those who are on another journey. Where do you fit in that? How do you perceive amateurs with differing license classes? Do you apply the same metric to moped, car and truck licenses? How do you compare yourself against those who are not amateurs and how did you step into your license? I'm going to stop with the questions now and leave you with a thought. The hobby of amateur radio is a playground where you have the freedom to explore radio and all that it offers, but nobody said that you need to limit yourself to radio. I'm Onno VK6FLAB

Duration:00:03:03

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How does your member society represent itself?

5/17/2025
Foundations of Amateur Radio 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,...

Duration:00:08:28

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A brief introduction to the HamSCI community

5/10/2025
Foundations of Amateur Radio 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

Duration:00:04:59

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Can we figure out how much the Sun really affects propagation?

5/3/2025
Foundations of Amateur Radio 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....

Duration:00:06:37

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Being an amateur without either radio or antenna

4/26/2025
Foundations of Amateur Radio 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

Duration:00:03:50

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Becoming Mode Agile

4/19/2025
Foundations of Amateur Radio Over the years I've talked about different ways of using our license to transmit. I've discussed things like modes such as voice AM, FM, and SSB, and digital modes like FT8, WSPR, RTTY, FreeDV, Hellschreiber, Olivia and even Morse code. Recently it occurred to me that there is something odd about how we do this as a community. Now that I've realised this it's hard to unsee. Let me see if I can get you to the same place of wonder. Why is it that we as amateurs only use one such mode at a time? Let me say that again. With all the modes we have available to us, why do we only use one mode at a time, why do we get our brain into the mindset of one activity, stop doing that in order to move to another mode? It's weird. Amateur radio is what's called "frequency agile". What I mean by that is we are not restricted to a fixed number of channels like most, if not all other radio users. We can set our transmission frequency to whatever we want, within the restrictions imposed by our license conditions, and start making noise. There's agreement on what mode you can use where, but within that comes a great deal of flexibility. We have the ability to find each other. Call CQ and if the band is open and your station is transmitting a signal, the chance is good that someone somewhere on planet Earth will respond. We change frequency at will, almost without thought, but why don't we do this with modes? The closest I've seen is local VHF and UHF contests where you get different points depending on which mode you're using, and even that seems hard fought. It's weird. We have an increasing range of Software Defined Radios, or SDR, where your voice, or incoming text, can be transformed to a different mode at the touch of a button, but we rarely if ever actually use this ability. In case you're thinking that the restriction relates to the availability of SDR in the average amateur radio shack, most amateur modes fit within a normal audio stream and that same flexibility could be applied to the vast majority of transmitters scattered around the globe, but to my knowledge, it isn't. Why is that? Better still, what can we do about it? Can we develop procedures and processes to make us more, let's call it "mode agile", giving us the ability to change mode at the same ease as we change frequency? What would a "mode and frequency agile" amateur look like? What processes would you use? Right now the best we have is to QSY, or announce that we're changing frequency, but I've never heard anyone use that to describe a change of mode. Of course it's possible that I've led a sheltered life and not been on-air enough, but if that's the case, I'd love to hear about it. So, what is stopping us from becoming even more flexible? Do we need to practice this, develop better tools, teach new amateurs, have multimode nets, invent new modes that share information across different modes simultaneously, build radios that can transmit on different frequencies, or something else? I'm Onno VK6FLAB

Duration:00:03:21

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Playing Games On-Air

4/12/2025
Foundations of Amateur Radio One of the basic aspects of being human and growing up is the process of learning. From a young age we explore our environment, play with others, have fun, fall over and bruise our knees, get up and try again. The playing aspect of this is often discussed as a way to keep things interesting. We add a competition element as an added incentive, so much so that we formaulate it into global competitions and call it sport. As a species it might surprise you that we spend about 1% of all Gross Domestic Product on sport, compared to science, which is about 2% of Global GDP. To give you some context, Agriculture accounts for about 4%, Manufacturing is 15%, Industry is about 26%, and Services account for roughly 62%. If you noticed that this is more than 100%, take it up with the World Bank, I'm a radio amateur, not an economist. Over the years I've explored different aspects of our chosen hobby of amateur radio. Time and again I return to experimentation, learning and having fun. Now I absolutely concede that my idea of fun and yours might not match, my GDP side quest is likely evidence of this, but in my opinion, this embodies the range of how we as a disparate community interact and exchange ideas across the ionosphere and closer to home using what we all can agree on is pretty close to magic. So, what is my point? Fair question. Having fun and learning. If you've ever had the opportunity to listen to aviation radio, and I'd encourage you to, the YouTube channel, VASAviation is a great place to start, comes with maps, explanations and subtitles. You'll discover that the complex domain of aviation communication is a dynamic environment where miscommunication matters and often has severe consequences. It's not all incidents and accidents though. If you look for Air Traffic Control legend "Kennedy Steve", you'll come across some of the funniest exchanges captured on ATC frequencies, all the while staying professional. So, how does this relate to amateur radio and you? Well, at the moment we have a few types of exchanges where we can practice our skills. The most obvious one is a thing we call contesting. A scored and rule bound activity where you're expected to exchange information and are declared the winner in a category. It's a little like sport and some have attempted to rephrase amateur radio contesting into a field that they're calling "radio sport". I have mixed feelings about this because there isn't much in the way of spectator activity associated with this. Another exchange is calling for DX contacts, sharing an exchange across distance, attempting to contact as many countries as possible, with the prize being membership into the fabled DXCC, the Century Club that acknowledges your prowess in making contact with a hundred countries. The most common exchange is the net or discussion group. It can be formal, like the weekly F-troop I've been hosting since 2011, or it can be ad hoc, one amateur chatting to another, sparking spontaneous discussion among several stations on frequency. We also do things like radio direction finding, someone sets up a transmitter and everyone playing tries to find the source as quickly as possible. First one to find it wins. It made me wonder if there are other things we might come up with. Has anyone played chess across HF? Or if you want to involve a larger group, what about playing Bingo! or a game of trivia? Anyone considered an MMORPG, or Massively Multiplayer Online Role Playing Game? The point being that we can play games, have fun, and learn in an environment where there are many factors affecting your ability to communicate, so we can all get better at keying the microphone and getting the message to the intended recipient. While we're having fun, nobody said that this needs to be a voice activity. An FT8 session could well be coerced into transmitting chess moves and nobody said that you have to do FT8 on the same frequency that WSJT-X is...

Duration:00:04:37

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What is Amateur Radio really about?

4/5/2025
Foundations of Amateur Radio When you join the community of radio amateurs, or when you briefly look over the shoulder of the nearest devotee, you're likely to discover that this is a hobby about a great many different ideas. Over the years I've discussed this aspect of our community repeatedly, talked about the rewards it brings you, about the camaraderie, about communication, learning, research, soldering, disaster recovery, public service, and all the other thousands of activities that this hobby represents to the world. While all those things might be true for some, they're not true for everyone. Many amateurs get excited about antennas, some immediately, some eventually. The same can be said for all the other points of what we think of when we discuss our hobby with others. Recently I saw a random comment on social media from a person who was having issues with their mobile phone on their property. I considered and ventured an opinion about what might be the cause and how they might go about discovering what was going on. I debated about how I signed off. It's a recurring dialogue, should I reveal upfront that I'm a radio amateur, or should I leave that to be discovered at a later date? In my experience, the wider society has a, let's call it a rocky relationship with our hobby. With the decrease in profile and numbers comes an increase in misconception about who it is that we are, and what it is that we do. At some level, there's an understanding that at some point this was an activity that grandpa might have engaged in, or it might be someone preparing for the end of the world, seeing our community as the way forward when all else fails, not at all helped by that slogan being used by a vocal amateur radio body, the ARRL. Given that, as I saw it, the issue was related to radio interference or a weak signal, I signed off, for better or worse, "Source: I'm a licensed radio amateur", and crossed my fingers. This started a discussion about the issue, which revealed that the person was having other problems with other communication tools in their remote village. I don't want to go into the specifics, because it's not about what their issue is, where they live and what other resources they might have access to, or not. It's about us, radio amateurs, because of course it is. Aside from the cringe associated with my sign-off, if you have suggestions on how to improve it, I'm all ears, I had a take-away that I thought was worth discussing. As I'm beginning to suspect, it's about the fundamental nature of our hobby, what it is and what it does. Troubleshooting. Let me say that again. Amateur Radio is fundamentally about "troubleshooting", in other words, systematically finding and fixing complex problems. So, let's explore this. If you consider we're all about communication in difficult environments, I'd point out that getting that message across is an exercise in troubleshooting. If you lean towards learning, then consider deciding what to study and why, more troubleshooting. If you suggest it's about soldering, what happens when you poke the leg of a component into the wrong hole? Do I really need to say it? Every time you think you've nailed down the intangible nature of our hobby, you can point at troubleshooting. Don't get me wrong, it's about having fun too, but you and I both know that fun is balanced by frustration, again, you guessed it, troubleshooting. In our increasingly technical, interconnected and complex world, the ancient pursuit of amateur radio is teaching you an invaluable skill, over and over again, all but inevitably: "The art of troubleshooting". So, next time you are asked why we should be doing this thing, why we are obsessed with this hobby, why we spend many hours, dollars and effort, it's all about finding out why something doesn't work as expected and funnily enough, the more you do it, the better you get. For radio amateurs, troubleshooting is our superpower. I'm Onno VK6FLAB

Duration:00:04:41

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What is the difference between a Dummy Load and an Antenna?

3/29/2025
Foundations of Amateur Radio Recently I started an experiment I plan to run for a year. Using a WSPR beacon and a dummy load I'm transmitting 200 mW, 24 hours a day across all bands supported by my hardware, in this case it covers 80m, 40m, 30m, 20m, 17m, 15m, 12m, and 10m. The aim of the experiment is to determine if, and to what extent my dummy load can be heard outside my shack. Why? Because I've not seen anyone do this and because a dummy load is widely believed to not radiate, despite evidence to the contrary. Together with the transmission side, I've also configured an RTL-SDR dongle, initially with the telescopic antenna it came with, now, since my HF antenna isn't being used by the beacon, I'm using it instead. It's about five metres away from the beacon, outside. It's a helically wound whip resonant on the 40m band built by Walter VK6BCP (SK). It's what I've been using as my main antenna for the past seven years or so. While I'm telling you this, my beacon has been heard by my dongle 1,182 times across all eight bands. Some of those reports were from inside the shack, some from outside, some while I was monitoring a single band, and for the past week or so, I've been monitoring all the bands supported by "rtlsdr_wsprd", 18 in all. Purposefully, this includes some bands that I'm not transmitting on, because who knows what kinds of harmonics I might discover? The receiver changes band every half hour, so over time when I monitor a band will shift across the day, this is deliberate. I don't know when a stray transmission might suddenly appear and this will give me the best chance of hearing it, short of using 18 different receivers. At this time, my beacon hasn't been heard by any other station. I'm not expecting it to, but that's why I'm doing this experiment in the first place. I'm not in any way reaching any sense of "DX on a dummy load", but it got me thinking. My beacon can be heard, albeit by me, from five meters away. So it's radiating to some extent. I've already discussed that this might come from the patch lead between the beacon and the dummy load, or it could be the dummy load itself, or some other aspect of the testing configuration. Regardless of the situation, there is a signal coming from my beacon that's wirelessly being heard by a receiver. That's the same as what you'd hope to achieve with any antenna. So, in what way are an antenna and a dummy load different, and in what way are they the same? Whenever someone asks this, the stock answer is that an antenna radiates and a dummy load doesn't. My experiment, 20 days in, has already proven that this distinction is incomplete, if not outright wrong. Even so, if we take it on face value, and we say, for argument's sake, that a dummy load doesn't radiate and an antenna does, then how do we materially distinguish between the two? How does an antenna compare to a dipole, Yagi or vertical antenna and where does the isotropic radiator fit in this? The best I've come up with so far is a spectrum line comparing the various elements. Let's say that at one end of the spectrum is a dummy load, at the other is an isotropic radiator, to refresh your memory, that's the ideal radiator, it radiates all RF energy in all directions equally. Somewhere between the two ends is a dipole. We might argue if the dipole sits equally between a dummy load and an isotropic radiator, but where does a Yagi or a vertical fit in relation to the dipole? Also, if you turn a Yagi in the other direction, does it change place? So, perfect this notion is not, but here's my question. What's the measurement along the axis between the dummy load and the isotropic radiator? It's not SWR, since the ideal antenna and a dummy load share the same SWR, unless this line is a circle that I don't know about. It might be Total Radiated Power expressed in Watts, but that seems counter intuitive. It would mean that in order to determine the effectiveness of an antenna we'd need to set-up in an...

Duration:00:05:57

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Echos from the past, 150 ms ago

3/22/2025
Foundations of Amateur Radio Recently Glynn VK6PAW and I had the opportunity to play radio. This isn't something that happens often so we try to make the most of it. For our efforts we had plenty of frustrations, to the point where we were joking that I should rename this to "Frustrations of Amateur Radio". That was until we heard something weird on-air. All setup shenanigans forgotten, we marvelled at the experience. I was playing around on the 10m band, trying to hear people making noise and potentially our first contact for the field day we were participating in, when I heard something odd. Two stations talking to each other, but the audio was strange. It was like they were doubling up, the same audio played a fraction of a second later, until that moment, something I've only ever heard in a radio studio whilst editing using a reel-to-reel tape machine with separate recording and playback heads. Having just started using a digital only radio, at first I thought this was an artefact of the radio. I took note of the frequency, 28.460 MHz and told Glynn about it. After we moved the telescopic vertical antenna to the analogue radio, we discovered that this was in fact real, not caused by the radios, no doubt a relief to the proud owner of both radios, Glynn, who was thinking more clearly than I. He took note of the callsigns, Dom VK2HJ and Yukiharu JE1CSW. Looking back now, an audio recording would have been helpful. At the time I suggested that this might be a case of long path and short path signals arriving at our station and being able to hear both. If you're not sure what that means, when you transmit, an antenna essentially radiates in all directions and signals travel all over the globe. Some head directly towards your destination, the short path, others head in exactly the opposite direction, taking the long way around Earth, the long path. You might think that the majority of contacts are made using the short path, but it regularly happens the other way around, where the long path is heard and the short path is not. As you might know, radio waves essentially bounce up and down between the ionosphere and Earth and it might happen that the signal arrives at the destination antenna, or it might happen that it bounces right over the top, making either short path or long path heard, or not. In this case, both arrived clearly audible. It wasn't until I sat down on the couch afterwards with a calculator that I was able to at least prove to my own satisfaction that this is what we heard. So, what were those calculations and what was the delay? The circumference of Earth is roughly 40,000 km. RF propagation travels at the speed of light, or about 300,000 km/s. It takes about 0.13 seconds or 130 milliseconds for a radio signal to travel around Earth. At this point you might realise that 40,000 km is measured at the surface, but ionospheric propagation happens in the ionosphere, making the circumference at the very top of the ionosphere about 45,000 km, which would take 150 ms. There are several things that need to line up for this all to work. Propagation aside, the distance between all three stations needs to be such that the number of hops between each combination is a whole number so we can all hear each other. As it happens, the distance between Perth in Western Australia and Maebashi City in Japan is pretty close to the distance between Goulburn in New South Wales and Japan, and the distance between Goulburn and Perth is roughly half that. Using back of napkin trigonometry, it appears that 27 hops around the planet are required to make this happen. That's five hops between Perth and Japan, and between Goulburn and Japan, and two hops between Goulburn and Perth, and 27 hops between Perth and Japan the long way around. Given that the F2 layer where the 10m signal is refracted exists between about 220 km and 800 km, we can estimate that the total delay for the long path is at least 144 ms. That doesn't really...

Duration:00:06:36

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Bald Yak 11, the goo between hardware and software

3/15/2025
Foundations of Amateur Radio Recently I received a question in relation to the Bald Yak project. If you're not familiar, "The Bald Yak project aims to create a modular, bidirectional and distributed signal processing and control system that leverages GNU Radio." I know that I've said that several times now and I suspect I'm going to say it several more times before we're done. I was asked about a specific radio and if this project could make it use a frequency that the supplied software didn't cover. The answer is deceptively simple and if you know me at all, you know what's coming: "It depends". As with many things, what it depends on is not fixed. I'll come back to the question, but I'm making a diversion past a magical place, the local hardware store. You can buy everything you need to build a house with the caveat that some assembly is required. GNU Radio is similar for building a signal processing system, but, wait for it, some assembly is required. In the context of GNU Radio this means that you'll need to collect all the bits and wire them together, fortunately you're unlikely to need Personal Protective Equipment or access to a First Aid Kit, unless of course the idea of playing with computers gives you palpitations, in which case I'd recommend that you go see your doctor. One of the less obvious things you'll come across with GNU Radio is how to bring signal processing into the physical realm, in other words, how do you get a signal into your computer, known as a "source", and get it out, called a "sink". The ability to talk to physical hardware arrives in roughly three different ways. Let's call them, "native", "library", and "abstraction". Native access requires that GNU Radio already knows about the hardware out of the box. Library access requires that the hardware manufacturer has provided software libraries, also known as drivers, allowing GNU Radio to communicate, and finally, abstraction is where a third party has written a library that knows how to talk to hardware from different manufacturers. The distinction between these is almost arbitrary, for example abstraction might require a driver from a hardware manufacturer. Similarly, because all this software is open source, native can include software from other projects, like the RTL-SDR blocks from Osmocom, Open Source Mobile Communications, and UHD blocks written by Ettus Research, which in turn can be seen as an abstraction. As I said, some assembly required. I will point out that this provides a great deal of flexibility, albeit at the cost of complexity, there's still no such thing as a free lunch. At this point you might shake your head and run away. I get that, it can be daunting. Before you do, consider the scenario where you have a working system and you upgrade your hardware. In a GNU Radio world you'll need to figure out how to configure the new hardware and then all your other stuff will continue to work. The alternative is upgrading each of your applications to connect to your new radio and in doing so, run the risk of making your old radio obsolete, even if you are collecting them .. let's say for posterity rather than hoarding .. because radio amateurs never hoard anything .. right? Back to the original question. Can GNU Radio make a radio use frequencies that the software that came with the radio cannot? As I said, "it depends". First of all, the hardware needs to actually be able to support the frequency. Then someone needs to have written a library to use that frequency, then GNU Radio needs to be able to use that library. That said, the chances of that happening are much higher than the chance of the hardware manufacturer rolling out this feature within your lifetime. Before you start yelling at me, yes, this is manufacturer dependent, some provide open source tools, many still don't. There are alternative ways to access different frequencies. The PlutoSDR is a computer and radio in a box. You can connect to it, change some...

Duration:00:05:57

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DX on a dummy load?

3/8/2025
Foundations of Amateur Radio Recently I made a joke about operating your station with a dummy load in response to John VA3KOT operating their station with the craziest antenna they ever used. It got me thinking about the ubiquitous "dummy load" as an antenna. Since becoming licensed I've spoken with several amateurs who tell a similar story, one comes to mind immediately, Lance VK6LR, now SK, who told me that they managed an unexpected 2m contact with another station using a dummy load, across the city. There's various versions of this doing the rounds, incandescent light bulbs used as both dummy load and antenna, coiled up roll of coax, everyone has a story to tell. Having spent several years proving that you can in fact use 10 mW and be heard on the other side of the planet, 13,945 km away, it tickled my fancy to think about what would happen if I replaced my antenna with a dummy load on purpose, as a test. For the past two or so months my WSPR beacon has been transmitting every ten minutes on the 15m band. It was heard 3,493 km away. Interestingly, even in that short amount of time, the radiation pattern of my antenna as seen on the "wspr.live" website shows a similar outline to the 10m transmissions I've been doing since late 2021. The number of total spots wasn't nearly as significant. I added a local receiver to my shack, just to prove that I was in fact transmitting, but there were plenty of days without a single external report, this in contrast with my 10m experiment where most days I had at least one or more reports from outside my shack, most of them outside my state. In other words, not every band gets the same kind of report. My license restricts me to the 80m, 40m, 15m, 10m, 2m and 70cm bands. The two antennas I've used so far are essentially limited to a single band, unless I start tuning it every time I change bands. As you might recall, I purchased a Hustler 6BTV antenna several years ago. Unfortunately, it's still sitting in the box. Climbing on my roof has not been an option for several years, but its time will come. The purpose of getting that antenna was specifically so I could use WSPR across multiple bands and see how propagation was in my shack in real-time without needing to rely on external forecasts or predictions. Switching to a dummy load has several benefits and impacts. First of all, it's not something I've seen anyone do. Then there's the idea of band hopping without needing to re-tune. The idea of radiating into something that's not supposed to radiate, is something that makes me smile. Given that each band has a different level of propagation, which ones should I choose? I could pick all the ones I'm licensed for, but that would leave out the WARC bands and the ever popular 20m band. What if I ignored convention and transmitted on all bands supported by my WSPR transmitter? Remember, I'm transmitting into a dummy load. By all accounts this should not radiate. It's taken as gospel by the amateur community that it doesn't. So, using a dummy load, one that's rated at 15 Watts between DC and 150 MHz, feeding it with 200 mW, or 23 dBm, my WSPR transmitter is currently merrily pinging away across 80m, 40m, 30m, 20m, 17m, 15m, 12m and 10m. If all goes to plan, nobody will ever hear this. That said, I can hear the uproar from here. What's the point? You're illegally transmitting on bands you're not licensed for. I'll report you to the regulator. Here's the point. The community and the regulator both state that the dummy load is the approved method for testing equipment. It's implied that the equipment will be happy and there will be no radiation. I'm testing and monitoring that assumption. I'm using all bands because if conventional wisdom is right, nobody will hear this. On the other hand, if conventional wisdom is wrong, there will be reports from bands where there are many people monitoring. I'll note a couple of other things. There's a patch lead between the WSPR transmitter...

Duration:00:07:00

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What's the story you'd like to tell yourself?

3/1/2025
Foundations of Amateur Radio When you joined the global community of radio amateurs you did so with a perspective that represented, at the time, what you thought the hobby was and how it operated. Since then, years, months, even days ago, that perspective has shifted in both subtle and obvious ways. One of my local amateur radio clubs, Ham College, was specifically formed to provide amateur radio education and license exams. It's where I went to get my Foundation license in 2010 and it's where many of the local amateurs have been taught over the years. For years I've been semi-regularly visiting Ham College during their Foundation course sessions. The purpose of my visit is to share what it's like to be an amateur, what things you don't really know about before you get licensed, and what things to look out for when you are. In general I talk about how to find the rest of the community, what you can expect and what to do with your license once you pass the exam. I try to cover the highlights without overwhelming the audience who technically are not yet amateurs at the time I'm sharing my thoughts. I talk about the endless variety of amateur radio activities, from activating anything that's not moving, or anything that is, depending on the level of adrenaline required, through contesting, camping and bushwalking, antennas, endless antennas and electronics. I talk about low power versus high power, and about community expectations in relation to upgrading to a "real" license. In case you're wondering, a "real" amateur license is any amateur license, including the Foundation license I hold, the introductory license. In my view, ultimately, this is your hobby, where you decide when and how much you want more responsibility and decide to pursue what this means for you. I discuss that the amateur radio community is global, attracting people from all walks of life, from submariners to scientists, from tow truck drivers to teachers, aged from nine to ninety, across all languages. I also touch on some of the less fun aspects of our hobby, specifically bullies. Over the years you've heard me discuss diversity, equity and inclusion in our community and also how there is a vocal minority who make it their mission to present obstacles to anyone who is different in any way. As I've said previously, the only antidote against this intimidation is to call it out and make your views heard, "this is not in the spirit of amateur radio", rather than change the dial and move on. In case you're wondering, changing the dial does nothing to address the issue and has a lasting effect on anyone else on frequency who might feel, or worse, has been, threatened by the bully. I also point out that this obnoxious behaviour is an exception, even if you feel personally attacked, and what you might do and whom you might talk to. For the record, my door is always open. Another example of what I discuss is the local amateur news and the weekly net for new and returning amateurs, F-Troop, midnight UTC on Saturday for an hour, a place where you can ask questions and discuss your issues with a supportive international community of amateurs. As you can tell, I'm not shy in voicing my opinion. Although I set myself a limit of 15 minutes, of late I've been wondering what other things might be of interest to someone who is just taking their first steps on their amateur radio adventure, hours away from taking their exam. What kinds of things would you have liked to know when you started your amateur journey? Get in touch, my address is cq@vk6flab.com. Don't be shy, express your opinion, it's the only thing that changes the world. What do you want the amateurs of tomorrow to know today? How would you equip yourself if you had the chance to start again? I'm Onno VK6FLAB

Duration:00:04:20