Foundations of Amateur Radio

Onno (VK6FLAB)
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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?".

  1. Aug 22

    Radio .. for the love of it

    Foundations of Amateur Radio During the week I was shown a photograph of a chalkboard standing on the sidewalk with one of those "Thought of the Day" quotes on it. Credit aside, since I've been unable to confirm it, despite multiple reverse image searches and attempts at author attribution, the sentiment stuck with me and the more I think about it, the more it resonates and this being radio, that works on so many levels. We proudly refer to our community as "amateur radio", hold it up as a badge of honour and tell everyone we know about it. Curiously, when you look in the dictionary, you see a litany of words with less than complementary connotations, like "freak", "dabbler", "crank", "neophyte", "inexpert", "unprofessional", "second-rate" and plenty more. In essence the word "amateur" is contrasted with the word "professional" and our community comes out looking worse for wear. I'm pointing this out because the experience is insidious. I've told the story of me attempting to report local radio broadcast interference to the regulator when I came upon an investigator who asked how I knew about interference. I explained that I was a licensed amateur. His response was: "I am a Professional". I can still hear the capital "P", now well over a decade later. It's also interesting when you talk to people outside the community who don't really get what it is that we do. Often they'll think that you're not serious about this and will unthinkingly dismiss your interest and pursuit, because it has the word "amateur" in it. So, what of this and the chalkboard? Here's the quote. "You say 'amateur' as if it's a dirty word. 'Amateur' comes from the Latin word 'amare' which means 'to love'. To do things for the love of it." As you might imagine, I went hunting to confirm this sentiment. It turns out that the word "amateur" comes from French "amateur", meaning, "person who cultivates an art or science for their pleasure", in turn that comes directly from Latin "amator", meaning "lover, one who loves", which stems from "amare", "to love". As an aside, "dilettante" from Italian "dilettare", comes from "to delight". It appears that once respectable pursuits in arts and science lost ground against professionalism and we ended up with a growing gap between formal and informal which increasingly is understood as dangerous, rather than charming. I think it's time to reclaim "amateur" and take "to love" to heart in our community. So .. "radio, for the love of it". That's what we do, what we are. And to be honest, I think that really says everything we need to remember. I'm Onno VK6FLAB

  2. 6d ago

    Give yourself a break!

    Foundations of Amateur Radio Over the past weeks, actually, probably months, the push to talk button on the radio I use for my weekly discussion net has been acting up. In the middle of an over it would sometimes cut-out for no particular reason. Being mindful and pushing harder didn't seem to make a blind bit of difference and no amount of fiddling with the cable helped either. Today I finally combined the act of remembering that this was a problem, with the availability of a spare moment, a passing level of personal health and no local distractions and as a bonus, you, or more accurately, my weekly article. As you might imagine, this is no mean feat and it doesn't happen very often, months apart, if not more, in this case. My first effort was to find my radio box. Except for the serial numbers, I have two visually identical boxes. One of them is sitting on a cupboard in my shack. I opened it up and the microphone I was hoping for, wasn't there. As you might gather, I have two radios. One is for my shack, the other for the car and portable operation, though currently that too is in the shack, connected to a separately purchased DTMF microphone. This means that I actually have three microphones, and thus the reason for hunting for the other box. As it turns out, it's safely stored in the garage where after squeezing between several recycling bins, shuffling between crates and shelving, lifting and moving several boxes, it revealed its, temporary, well several years now, storage location. I retrieved the box, put everything else back where I found it, then brought the box into the shack and promptly started sneezing, because dust and allergies. Opening the box confirmed that my brain is still, at least partially, functioning, since the microphone I remembered being stored there was in fact exactly where I thought it would be. I swapped out the microphone, turned on the radio, tested it with a repeater kerplunk and called it done. In the process of removing the "faulty" microphone I noticed that the cable appeared to be swapped end-for-end. I don't know if that was the root cause of the issue, but the confluence of factors for this adventure ran out, so that's a project for future me. I did find a sandwich bag to put the microphone into and labelled it as being possibly suspect, noted that I swapped the cable end-for-end, but left it untested. I can remember some stuff, but obviously I'm not as smart as you think I am. So .. why am I telling you this in so many words? It occurred to me that all too often we look at others asking ourselves "why didn't you fix that, it's so easy", when the reality might be somewhat different. In my case, there's plenty of moving parts, some of which actively get in the way, some passively. In this case a seemingly simple task took well over an hour, rather than the 15 minutes I'd budgeted for. Next time it's fine to give yourself some slack and take a moment, rather than beat yourself up about something you failed to achieve. You need to keep reminding yourself that amateur radio is a hobby, not a profession and progress can be made one step at a time. Time will tell if I fixed my microphone issue or just took a step on the troubleshooting path. I'm Onno VK6FLAB

  3. Aug 8

    Emergency response reality check

    Foundations of Amateur Radio Recently I explored the nature of amateur radio emergency response. I received a few replies providing an insight into the on the ground reality and it encouraged me to dig into this a little more. I'll start with some context. Early in my amateur adventures I became aware of the Wireless Institute of Australia's efforts in encouraging people to become familiar with emergency procedures. It introduced a course titled "Introduction to Public Safety Training for Radio Amateurs", specifically to achieve a Certificate II in Public Safety. I dutifully downloaded the materials, went to my local office supply store and had the documents printed out. The bill was hundreds of dollars as I recall, as much as I paid for my new FT-857d, because the dozens of PDF documents had little colour logos scattered throughout, because of course they did. After getting over the bill shock, I discovered that you could only do this course if you had an advanced amateur license. Not that this requirement makes any sense, since you're not operating on amateur radio frequencies or using amateur radio equipment, but I digress. To add insult to injury, today I dug up that 2011 manual, well, one of the four volumes sitting on my shelf, and discovered that for example, the module for "Communication in the Workplace" is actually a standard training module offered throughout Australia. In other words, the Wireless Institute's attempt at linking amateur radio to emergency response was a set of training modules that made you into an Emergency Communications Officer with, I might add, no guarantee of engagement by your local emergency service. As far as I can tell, this is no longer offered but the evidence shows that it continues to shape amateur radio emergency policy a decade and a half later. I set out to discover if things had improved, starting with a search for "WICEN procedures", WICEN being the Wireless Institute Civil Emergency Network, the equivalent of ARES, the Amateur Radio Emergency Service in the United States, RAYNET, Radio Amateurs Emergency Network in the United Kingdom, DARES, Dutch Amateur Radio Emergency Service and many others. I was pleasantly surprised to find many pages with results. Less pleasant was to discover that many, if not most of them, hadn't been updated since 2011, that's if they were dated at all. As an aside, dating this kind of information is in my opinion crucial. A list of repeater frequencies is absolutely irrelevant if it's more than a year old, but if the information has no date, you have no idea if you're dealing with a current list or one written when Netscape was still in business. For example, the WICEN Tasmania (South) website has lots of information, but there's absolutely no indication of how old it is, unless you take the "Adobe Flash Player is no longer supported" in the header as a sign that it was last updated before 2017 when Flash was depreciated. Their "Equine Endurance Ride Tracking" has a version number, but no indication of when it was updated. I did find a Voice Procedure Training Module dated 16 June 2011, so that's something. Lest you think I'm picking on Tasmania, WICEN Victoria has plenty of information, all dated 2011, well, apart from the 1994 and 1998 manuals. WICEN Bundaberg has information, at least some of it dated, but published in August 2012. WICEN WA has a snazzy website which contains the outlines of something, but it's unclear where it's at and their homepage states that it's in a "rebuilding phase". I'll note that the main wicen.org.au domain links to eight WICEN organisations, but the list is nascent at best and while it serves as the Australian WICEN landing page, it has no other information. Not even the Wireless Institute itself provides a full list of its own WICEN affiliated clubs and associations. Age and accuracy aside, one thing all these results appear to have in common is the unstated burning desire to become official Emergency Communications Officers, with instructions on pro-words, standard phrases, voice procedures and integration with the rest of the official Emergency Communication community. While I get that this was the Wireless Institute aim back in 2011, is that still relevant today? Is being a radio amateur the starting point for becoming an operator in an emergency radio bunker, or is that a parallel path that radio amateurs might take? Let me be explicit here. Are we as radio amateurs best suited to train other radio amateurs to become certified State Emergency Service volunteers, or should we join the local SES and participate in their training? It goes back to the underlying premise and its current implementation, such as it is, amateur radio's attempt at claiming an emergency communications role in order to justify its use of radio spectrum. Don't get me wrong. I have no beef with providing emergency communications, but effectiveness is important. Volunteer hours are a strictly limited resource and it seems to me that the path we've been on since at least 2011 is attempting to duplicate an existing system with, I suspect, very limited real world application. So, what should we do about it? Although it's incomplete, undated and without version numbers, the WICEN WA website has a list of how emergency communications are activated, who does what and when and in which order. That's the only place I've ever seen such a list. It's a start. It appears that some parts of WICEN are attempting to roll out a permanent HF data network. The choice of band is curious, 80m, a band not known for local communications, daytime communications, or small and easily deployable antennas, ask any portable operator. In contrast, the Philippine Amateur Radio Emergency Data Network, PAREDN or DX1PRD, uses 2m and 70cm for most of its network which also has an active status dashboard, something which I have yet to discover anywhere in Australia. Within the various emergency systems across the globe, two proprietary tools seem to have taken hold, Winlink and VARA. The first providing a mechanism for message exchange with an associated global network of receivers, the latter a way of transmitting it across radio. Together they claim to provide the basics of a parallel Internet for "when the Internet goes down, mobile phone networks fail or natural disasters isolate communities". Frankly, bandwidth considerations alone will reveal that it's the same kind of absurd claim that the ARRL made famous: "When all else fails" The tools, Winlink and VARA, are claimed to be cross-platform, but all links supplied by WICEN sites I found are for Windows only, closed source, or worse, stuck behind a user account login. There are efforts underway for open source replacements for both VARA and Winlink, according to GitHub both replacement projects started in 2023, but this software is in active development and I see little evidence of wide adoption of either at this stage, that's not to say it won't be, just that it isn't yet. As soon as the proprietary tools change protocol, these projects will stop working until the new protocol has been reverse engineered. Hardly a recipe for robustness. In case you think this is a new effort, the WICEN Victoria website has Winlink presentations as recent as 2012. I'll leave you to contemplate if any of this makes sense. Unrelated, I'm recovering from a cold and some wondered recently if I was experimenting with voice cloning. It's a question that's been put to me in other forms as well, several people over the years articulating that they thought I was a bot. Let me point out that the whole point of my contribution here is to learn, document and share it with you. If I used Assumed Intelligence, or AI, and Unsupervised Text Extruders, or LLMs to do that, there's no learning for me and subsequently no reason for spending time with you. As an aside, I tend to use "my cat" as a phrase to replace any instance of OpenAI, Anthropic, Claude, ChatGPT, Gemini and Co-pilot and based on the growing list of companies focused on this, I find it helps retain my sanity. I'll leave you with a question. While the WIA claims that WICEN is "totally independent from the WIA", even though it obviously has its fingerprints all over it, who is running this show and perhaps more importantly, who is helping? I'm Onno VK6FLAB

  4. Aug 1

    An emergency response

    Foundations of Amateur Radio Previously I've talked about one of the often lauded cornerstones of the amateur radio community, namely Emergency Response, and to be frank, I questioned then, as I do now, the reality of this, at the very least, perceived, foundational aspect of our global hobby. Before you get out the caps lock key, let me assure you that I'm aware of sporadic examples of heroic efforts made by members of our community to save lives that are held up as examples of amateur radio emergency responses. What I'm questioning is related to our collective effectiveness. We have global and increasing occurrences of wild or bush fires, we have earthquakes and tsunamis, storms, hurricanes, cyclones or typhoons, whatever you call the vortex of destruction, and global news media ensures that we hear about it within hours if not seconds. Social media provides us with mobile phone footage dubbed with expert audio to explain the latest tragedy to the rest of us. What we don't see is what happens next, while the power is out, the internet is down, mobile phones aren't working anymore and survivors are fighting tooth and nail for their return to normalcy, or at least what's left of it. It struck me that one thing I never see discussed and haven't ever discussed in over a decade and a half I've been here, is the amateur radio interface with the rest of the world. A comment I see often is that Internet connected amateur radio, like Echolink, AllStarLink and IRLP, aren't real radio and that real amateurs use RF. HF radio for the win right? What do you think the relevance of HF radio is to a family member living in the next town after a disaster, or a parent looking for their lost child? How do ordinary people benefit from the radio amateur who lives on their street, or the one who travels into the disaster zone? Ultimately, if we are to take our claimed emergency response role seriously, we as a community of radio amateurs need to consider just what it is that we can offer to the people around us in the case of an emergency. Might what we offer look like a Wi-Fi base station that's connected to the rest of the world via an IP link that happens to be running on 2m or 70cm during an emergency? Or could what we offer be described as an Amateur Radio Short Message Service, what about transmitting a DVB-T dashboard that's being updated over LoRaWAN, or a local voice relay service? Where's the infrastructure, planning, preparation and training for that? Where's the documentation for it? How are we telling the local community about it? How well do we even do outage notifications within our community, let alone outside it? The point being that there are amateurs who beat their chest about emergency preparedness and, bluntly, have little or nothing to show for it. Don't get me wrong, this isn't limited to the amateur radio community. For a few weeks I became an aspirant member of a local emergency response team, right until I discovered that their biggest issue was that their user base, the local volunteer bushfire brigades, didn't really know how to use their radio repeater system and my suggestion to go and visit each one on a rotation basis and train them was met with snorts of derision and laughter. Do you really want an emergency response to be ad hoc? "Oh, sorry, I'm missing a cable and I can't connect this to that, I'll sort it out for next time." The increased interest in the various "OTA" or "On The Air" pursuits, Parks, Peaks, Summits, Bunkers, Castles, Waterways, Islands, Lakes, Libraries, Lighthouses and Toilets to name a few, are all helping amateurs practice with the "getting on-air and make noise using a temporary installation" part of an emergency response, but few of those activities interact with the general public in any way. Ironically, the local Wireless Civil Emergency Network, or WICEN, is at least doing some community outreach by providing radio infrastructure to a few local events. It's a start, but still a very long way from interacting with your next door neighbour in preparation for a massive storm and subsequent power outage. Here's the thing. There's no end-to-end anything. Is ad hoc sticky tape and baling wire really the way you want our amateur community to respond to an emergency? Is emergency response a fanciful concept, or are there things we as a community could put together to make it reality? I'm Onno VK6FLAB

  5. Jul 25

    CME, Wind, Flares, Flux and Geomagnetic Storms .. say what?

    Foundations of Amateur Radio When the Sun burps, something that it does regularly, the mainstream media starts talking about aurorae and optionally the end of the civilised world, not always as clinically as that. What's not talked about, let alone explained, is the nature of the solar burp. You've likely heard the terms Coronal Mass Ejection, or CME, Solar Flare and perhaps Solar Wind, Solar and Geomagnetic Storm, and Solar Flux, but what do these terms actually mean and how do they relate? Let's start with some basic numbers. Our Sun is 150 million kilometres away from Earth. As seen from Earth, the Sun rotates on its axis every 27 days, called a synodic rotation period, because while the Sun is rotating, Earth is moving too. If that wasn't enough, the Sun isn't solid, depending on where you're looking at it, rotation happens at different speeds, faster at the equator, slower at the poles. You might have heard of the Solar Cycle, an 11 year period during which solar activity steadily increases, near the maximum activity its magnetic poles flip from North to South and activity slowly decreases until the cycle starts again. Until quite recently we've deduced this by counting the number of dark areas, called sunspots, on the surface of the Sun. All this to say that our Sun is one massively dynamic environment and with it come a whole lot of processes that science is still discovering. The YouTube channel Astrum has a fascinating video called "We Didn't Predict the Sun Would Do This", that describes much of what we're still learning. We experience the Sun as a source of light, but as a radio amateur you know that light only represents a small set of frequencies in the radio spectrum, it's better to think of the Sun as a radio source, emitting many frequencies at once. The strength of this is measured at 2.8 GHz three times a day at 17:00, 20:00 and 23:00 UTC at the Dominion Radio Astrophysical Observatory in Penticton, British Columbia, Canada. This measurement, the Solar Flux gives a good indication of the level of solar activity. Adjusted for the varying distance between Earth and the Sun, a Solar Flux Index, or SFI, below 70 means that solar activity is very low, above 150 is considered very high activity. In addition to radio waves, the Sun also spits out a continuous wave of particles. Different parts of the Sun emit these at different speeds, varying between 300 and 800 km/s. These particles, the Solar Wind, exist throughout our Solar system. Because the Sun rotates and the particles aren't being emitted evenly we experience the solar wind as having a 27 day cycle. Think of a water filled beach-ball hanging from a rope with a hole in it, spinning, creating spirals of water. Stand in one spot and every time the ball rotates, you get hit by water. When the Sun burps, often at a sunspot, where concentrations of magnetic fields cool the surface, bursts of electromagnetic radiation are generated throughout the radio spectrum. Measured in Watts per square meter, this radiation is called a Solar Flare. Travelling at the speed of light, it takes about nine minutes to arrive at Earth. Sunspot and solar activity is used to model and predict the potential for solar flares. Strength is classified in four stages, class B being the weakest, through C, M, and class X being the strongest, each ten times more powerful than the previous. Within each class, numbers 1 through 9 serve to provide additional resolution, X2 being twice as strong as X1. The most powerful flare on record was estimated to be about X45, recorded on 4 November 2003, when at strength X17 the sensors overloaded. Some solar flares coincide with a massive eruption of particles, some of which are ejected violently, called a Coronal Mass Ejection or CME. A slow CME, travelling at 500 km/s might take three days to hit Earth, an extreme CME, travelling at up to 2,500 km/s might arrive in 16 hours. As the CME particles arrive, they distort Earth's geomagnetic field and depending on the severity, might cause a geomagnetic storm where fields are pushed closer towards Earth causing visual effects as aurorae. Recovery generally takes up to two days, but in extreme cases has been observed to take four. Disturbances of Earth's magnetic field are highly variable and are expressed in several different ways, the K, Kp, A, Ap and G indices. The K-index measured at individual observatories, ranges from 0 to 9 over a three hour period represents the maximum horizontal fluctuation in the geomagnetic field. Values of 5 and above indicating a geomagnetic storm. The planetary Kp-index represents a weighted average of 13 mid-latitude observatories. The National Oceanic and Atmospheric Administration, or NOAA uses a G-scale, between 1 and 5, equivalent to a Kp-index between 5 and 9. The A-index is derived over eight K-index readings over a 24 hour UTC period at a particular observatory, below 20 is calm, between 20 and 50 is unsettled and above 50 is a stormy day. The Ap-index is an averaged planetary index based on data from a set of specific Kp stations. There's more. In 1760, a publication by Swiss polymath Leonard Euler indicated the existence of three stationary points between any two large bodies, known today as L1, L2 and L3. In 1772, Italian born, French mathematician, physicist and astronomer, Joseph-Louis Lagrange, discovered two more stationary points, L4 and L5. Known as the Euler-Lagrange, or Lagrange Points, some of these locations are being used today for solar observations, predictions and early warning systems. Launched on 24 September 2025 and in orbit at L1, between the Sun and Earth, at a distance of 1.5 million kilometres from Earth, the SOLAR-1 satellite acts as an early warning for solar storms. Since particles travel slower than the speed of light, this provides about 15 minutes warning for extreme CME's and longer for slower events. It became fully operational on the 10th of June, 2026. As part of the same Space Situational Awareness Programme as SOLAR-1 is the European Space Agency's Vigil space mission. Intended to be placed at L5, 150 million kilometres from Earth, it will be able to observe solar activity as the Sun rotates towards Earth and reports indicate that this will increase early CME warning by two to four hours. Vigil will also allow for four to five day space weather forecasts. It's planned for launch in 2031, mind you, it's going to take three years to get to L5. Aimed with all that information, I was actually, for the first time, able to at least understand the solar report in my Mastodon feed. "The Sunspot Number has dropped to 88. The Solar Flux Index has risen to 149. G1-class geomagnetic storms are predicted for today. A-Index is 14, K-Index is 2. Chance of flares today: 55% for M-Class, 10% for X-Class." Armed with that information I'm going to make myself a cuppa and figure out what my WSPR beacon has to say about all this. I'm Onno VK6FLAB

  6. Jul 18

    The power of patience and pacing

    Foundations of Amateur Radio One of the more, let's call it challenging, skills to learn in amateur radio is the pace of the process. For many new amateurs I meet, face-to-face, on-air or online, the excitement to get started, to get on-air, to make a contact, to do something, anything, is contagious. It's absolutely delightful to hear the reports of victory and triumph in the face of adversity, and truth be told, it's worth celebrating, more than we often do in this community. So, let's start there, if you've made it on-air, congratulations, well-done, very nice! If you feel so inclined, perhaps you'd like to document this achievement. I'll hasten to add, this documentation is for your own records, more on that in a moment. I will point out that you are under absolutely no obligation to create documentation, and even less obligation to make it public, you know, aside from any record keeping requirements set-out by your regulator. Now that you've made this first on-air contact, your obvious next activity is to do it again, perhaps with a slight variation in frequency, location, antenna or radio. This process will likely continue until at some point making contacts like this is no longer exciting or rewarding. Some amateurs stop here and are never heard of again, and while that's disappointing, that is absolutely your prerogative, since this is a hobby, more precisely, your hobby. I'm mentioning this because it's all too easy to forget this fundamental aspect of our community, especially when you're swept up in the excitement of it all. Over the years I've experienced the excitement associated with this hobby and the community first hand. I've also witnessed the activities of others, amateurs who come in with their tail wagging, running from here to there, sniffing all the bushes and drooling all over their homework, imagine a puppy exploring their new forever home and you'll get the idea. Just like puppies, these excited amateurs get to a point, about two or so years in, sometimes more, sometimes less, and then basically stop, exhausted, dissatisfied, disillusioned and disheartened they depart the hobby, never to be seen again. It reminds me a lot of new employees at the computing help-desk where I used to work. After about six months of running around, putting in long hours, pleasing every customer, putting on a smile all day long, dealing with the emotions of being the first point of call for every problem, many succumbed to burn-out and quit. It occurred to me the other day that the radio puppies are following the same pattern, albeit over a longer time span. And with that insight comes the realisation that we can do something about this. As I told my new colleagues at the help-desk at the time, to slow down, I can use the very same advice to you and for similar reasons. The field of computing is bound by imagination, so, essentially it's unlimited. The same is true for amateur radio. The hobby you perhaps unwittingly stepped into turns out to be unlimited as well. The implications of this are that one lifetime is not sufficient to know everything about either computers or amateur radio, and much more than three lifetimes if you choose both, ask me how I know. With that comes the realisation that patience and persistence pays off. The journey, not the destination, is the reward. So, if that's the case, what does this mean for you? For starters, it means that each contribution you make is valuable. It means that finding new stuff is inevitable and it means that you're not alone on this journey. So, next time you feel that you've done all there is to do in this hobby, think again. Each time you do something, anything, celebrate it. I did say I'd come back to documentation. Hopefully, by now you'll understand what the meaning of it is. If not, permit me to make an observation. If you don't know or remember what you did, how will you know that you're on a journey? I'm Onno VK6FLAB

  7. Jul 11

    The things you hear when you least expect it.

    Foundations of Amateur Radio The other day a friend of mine mentioned in passing that they'd hooked their Home Assistant dashboard to an RTL-SDR dongle to listen to the various ISM bands. If that sounds like gibberish, let me elaborate. "Home Assistant" is a tool that, among other things, allows you to control devices throughout your house, think lights, vacuum cleaner, air conditioning, and power sockets. It turns out that there are various plug-ins that allow you to connect it to a tool called "rtl_433", more on that in a moment. ISM, or Industrial Scientific and Medical, is a global collection of 13 radio bands, regulated by the ITU, the International Telecommunications Union, where devices are permitted to transmit all different types of signals, think microwave ovens, NFC, or Near Field Communications, Wi-Fi, Bluetooth, but also weather stations, security devices, battery monitors, tyre pressure monitors, remote keyless entry, garage door openers and plenty more. The most "well known" ISM band is 433 MHz, but the most used ones are those we think of as Wi-Fi bands, 2.4 and 5.8 GHz. It sometimes comes as a surprise that Bluetooth and Wi-Fi share the same frequencies with each other and many different bits of technology. While I'm here, I'll also point out that there are ISM allocations within the HF bands and up to 245 GHz, so plenty of spectrum to explore. A different friend heard about my challenges with two remote controls, came by for a coffee and dropped off a frequency counter and left me to determine what type of remotes I had in my hands, since labelling was absent. After charging this sparkly new gadget I spent a while trying to make it do the needful, but ultimately, despite trying in multiple locations without local interference was unsuccessful, this likely caused by the nincompoop behind the controls, but I digress. It occurred to me that an RTL-SDR dongle is perfectly suited to the job, as long as I can scan through the various frequencies and discover just which ones were associated with my cantankerous remotes. As is my want, I got distracted by installing "rtl_433". I have to tell you, just plugging in an antenna into an RTL-SDR dongle, I'm currently using my 2m and 70cm dual band antenna, running the tool and looking at the log, in the last half hour alone, I've seen 372 reports, across 16 devices, including several cars and a truck, weather stations, security devices and plenty more; half an hour later we're up to 22 devices and 771 reports, and 24 hours in we're up to 128 devices, nearing 17,000 reports. I'll note that this is using an RTL-SDR dongle, no fancy radio, no filtering, no interference rejection, all straight from the device. As you might expect, the reports keep trickling in, every 15 seconds or so there's a new decode and at this point I'm pretty sure I don't need to invest in a weather station in the near future, and if I figure out which Hyundai is driving around with low tyre pressure, I'll let them know. Also, because I'm not just lollygagging, my remotes don't appear to emit anything that rtl_433 can decode, but I did notice that the reports stopped coming in while the remote was active, so I suppose that's progress. In-case you're wondering, within "Fifty Things you can do with a Software Defined Radio", this is number "11: Read your neighbors'[sic] sensors". At this point I hear the calls from the peanut gallery: "But .. but .. but, this isn't amateur radio" .. to which I say, "Really?" In other words, amateur radio is what you make it and right now I'm interested in figuring out why my remotes are acting up and what better way than to play with radio, at whatever frequency takes my fancy. I wonder if there's any HF gadgets I can monitor. I'm Onno VK6FLAB

  8. Jul 4

    What does expertise look like?

    Foundations of Amateur Radio Over the years I've had the opportunity to operate my station with other amateurs in close proximity. From a community perspective, this is loads of fun; from a radio perspective it's been frustrating to put it mildly. For example if you're operating on say 40m and your friends are playing on 20m or 15m, if you're not careful, you'll all end up hating each other at the end of the weekend due to the harmonic nature of the amateur bands. Imagine my surprise when Keith W6KME mentioned in passing that together with the other members of the Conejo Valley Amateur Radio Club, callsign AA6CV, managed to operate 25 stations within a 300 meter circle from each other, without commercial electricity. Oh, did I mention, the antennas have to be within the circle and they operated on 80m, 40m, 20m, 15m, 10m and 6m, no doubt there were other bands that I'm not aware of, and if that wasn't impressive enough, about a third of the space was allocated to public information. You can see their efforts at cvarc.org Mind. Blown. Given my less than exciting experiences to date, my first question to Keith was about inter station interference and Keith pointed me at a freely available article published in the May 2026 edition of QST magazine, titled "Station Setup Techniques to Prevent Field Day RFI" by Conrad N2YCH, which discusses a whole range of stations, including the AA6CV field day station. Very informative. One takeaway was that this is within the realm of doable for all of us. Another takeaway was that the stations in the article all appear to be high power, which is not something I have experience with, nor the budget for. I recalled that my local friends had done some abortive attempts at using so-called coax-stub filters. Essentially several specific lengths of coax that act as filters at particular frequencies, either to pass that frequency, so you can hear it, or to block the frequency, so you don't hear it. If you have a roll of coax, this could be a pretty cost effective way of making some field day filters. Somewhat tangentially, the other day I was having a conversation with a friend about technology in the world. We're both of a similar age and memories of Commodore Vic 20, MOS Technologies, bulletin boards and serial port multiplexers punctuated our discussion. At one point my friend commented on the vast knowledge and expertise held by a respected colleague, the implication being that we did not fall into that category. Given that we'd just spent the better part of 90 minutes discussing technology going back multiple decades and their impact in the world today, I pointed out that we too fell into that "expert" category. It's funny, even though I've been in computing for over 40 years and written over 780 articles on the topic of amateur radio, I don't particularly think of myself as an "expert". I think I know enough to know that there's plenty I know absolutely nothing about, and lots I know enough about to know that I'm dangerous. Imagine my surprise when I searched for "rg6 coax stub filters" and discovered a post on Hackaday, called "Coax Stub Filters Demystified". It opens up with the sentence "Unless you hold a First Degree RF Wizard rating, chances are good that coax stubs seem a bit baffling to you." and goes on to introduce some interesting observations and links to a YouTube video by "Fesz Electronics" cunningly titled "Coax Stub Filters", which includes a whole lot of detailed information, simulation and visualisation of various aspects of this phenomenon, including the impact of different types of coax, combinations of these and countless other variations, that I think is aptly captured under "RF Wizard", even if some Hackaday comments were dismissive. It brings me back to the underlying conversation around expertise. Everyone brings their own journey to this hobby. For some a coax stub filter is trivial, for others it's magical if not magic. I think that given the complexity of the interaction between multiple filters as shown by Fesz Electronics in their video, it's more complex than might appear at first glance. Now all I have to do is figure out if it's possible for me to create a set of stubs for my next shared field day. I'm thinking it would help if it was modular, so we can mix and match, but that's a challenge for next time I'm left alone near a pile of coax with a VNA, cutters, coax strippers, compression tool and a packet of F-type compression connectors. I'm Onno VK6FLAB

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About

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?".

Information

  • Creator
    Onno (VK6FLAB)
  • Years Active
    2015 - 2026
  • Episodes
    598
  • Rating
    Clean
  • Copyright
    ℗ & © 2015 - 2026 Onno Benschop
  • Show Website
    Foundations of Amateur Radio

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