Advertise on podcast: Foundations of Amateur Radio

Foundations of Amateur Radio I recently expressed the notion of using a PlutoSDR as a replacement for an oscilloscope, a spectrum analyser, and perhaps even a vector network analyser. I can add signal generator to that list and you get the notion that this one device might replace a bunch of tools in your shack. So .. I set out to come up with a minimum viable product to see what I might discover. There are days when you get out of bed with a spring in your step, only to end the day exhausted and thoroughly defeated. Given the chance, the next day, you get out of bed and try again. Fortunately for me, I have a full head of hair and my yak shaving barely made a dent and as a bonus, I learnt something, which is always nice. The short version is that you should use a USB Y-adaptor or splitter to ensure that your PlutoSDR has enough juice to power a USB Ethernet dongle. That statement alone is worth at least a combined fifteen hours of Yak Shaving. Without this turning into a PlutoSDR specific troubleshooting saga .. for reasons I don't understand, plugging the power supply into the Pluto power socket and a USB Ethernet dongle into the accessory port doesn't work, but plugging both into a Y-adaptor and that into the accessory port makes all the blinkenlights work, even those on your network switch. As I said, fifteen hours. So, what does this buy me, other than an appreciation for subtlety? It gives me network access to my PlutoSDR, which makes it possible to connect to it using GNU Radio running on a different computer, which then allows me to experiment. Before starting this side-quest into connecting to my Pluto, I went on the hunt for some example code. Jon Kraft, who is a senior staff Field Applications Engineer at Analog Devices, whom I came across first on YouTube, where he's been playing with beam-forming and other nifty RF phenomena, also has a GitHub repository with some PlutoSDR examples for use with GNU Radio. These examples are pretty straight forward, essentially connecting to a PlutoSDR, setting the centre frequency and extracting a bunch of RF and visualising it. Essentially what you'd want in some testing gear. After playing around for a bit with Jon's examples, I'm able to see radio spectrum, across the network, on my screen, using GNU Radio. Eagle eyed observers will note that I already achieved this with an RTL-SDR dongle and indeed I did. A few differences. I have access to a frequency range between 70 MHz and 6 GHz and I have the ability to transmit. Of course this doesn't yet get us to the point of replacing test gear, but I think it paves the way to a collection of experiments that will. If you're unfamiliar the Bald Yak project aims to create a modular, bidirectional and distributed signal processing and control system that leverages GNU Radio. It's called Bald Yak because by the time I'm done, the Yak is likely well and truly shaved. So, my oscilloscope and other tools adventure is an example of what Bald Yak might facilitate. In radio terms there's very little to distinguish this type of tool from a transmitter running your favourite mode, and it allows me to experiment with a different radio back-end. Full disclosure, I'm still trying to work out how to do this using SoapySDR, because if you remember, that will allow me to connect to any device, for now, this is using a PlutoSDR source and sink. While we're on the subject of Soapy, I did start digging into SoapyAudio and the idea of making a more universal module that will allow amateur radios for both receive and transmit using Soapy, but I came unstuck when I discovered that the example plug-in code is essentially an empty file with the programming equivalent of "here be dragons". I'll likely come back to it, but not today. Now, I do need to make some disclaimers because I know that there are plenty of caveats I've glossed over here. I think much of it is covered with the word "calibration". A PlutoSDR is not a laboratory grade device. It isn't calibrated in any way, it's likely unstable, connectivity across the network is likely to be choppy, and plenty more issues like this. In other words, if you come away from this thinking we're going to be building something to replace measuring gear you can buy for the price of a small car, you're going to be disappointed. However, if you're here for "Wow, cool, you can do that, for a couple of hundred bucks?", you've come to the right place. Also, I'm aware of the Analog Devices "IIO Oscilloscope", that it's extensible, and even has a plug-in specification, but what it doesn't have is GNU Radio, which is I want to use for a whole lot of reasons, least of which that it isn't hardware dependent. As I've said before, when I have something to show-and-tell, you'll be the first to know. In the meantime, you could do worse than look for Jon Kraft's GitHub or his RadioKrafter YouTube efforts and have some fun yourself, that's Jon, no "H" and Kraft with a "K". I'm Onno VK6FLAB

Foundations of Amateur Radio Launched into your amateur radio adventure you're faced with figuring out what you need to fly. If you have a web browser, you can start listening to a massive array of online radio sources .. today. Beyond that, a handheld radio is often the first purchase for a new amateur, more often than not followed by the acquisition of a more advanced radio and associated paraphernalia, antenna, coax, power supply and the like. A video of forging the "Most Iconic Swedish Axe", by Torbjorn Ahman, a Swedish Blacksmith, started off with making several tools, before the axe forging itself got underway. It reminded me that in the amateur radio community we often talk about radio with rarely any mention of any toolkit. Spend six seconds thinking about this and you'll likely come up with a soldering iron and a multimeter as your next investment, but what happens after that? While not universal, truth be told, my soldering iron has very little use, though half a century ago it was probably essential. My multimeter gets more use, even though it really doesn't do any radio tricks. Its most used feature is continuity testing. One proper bit of test gear is an antenna analyser that we use most times anyone plays with antennas. Several years ago, I was given a lovely NanoVNA which gets a regular workout though calibration is a bit cumbersome. I was also given an inline power meter that provides all manner of battery health information. I take it to every portable operation. Gadgets aside, the tools I use more than all of these put together are a quality wire cutter and an Anderson Powerpole crimper with all the connector housing colours. There's also a comprehensive set of screwdriver bits, enabling access to more equipment than I have time to investigate. A 15 Watt dummy load, good to 150 MHz, gets regular use, and to complete the picture, underneath my desk is a HP 606A signal generator that I'm scared to restore. Last time I went near it, I managed to trip the house RCD for reasons I still don't understand. There's other stuff in boxes and drawers, but I clearly don't use them enough to come to mind. Unremarked is my computing infrastructure. Until a couple of years ago that consisted of a 27" iMac, vintage 2015. Expanded to 64 GB of RAM, it ran all my software using VMware, sometimes a dozen or so virtual computers simultaneously. It died in 2024 when the power cord managed to short itself on my portable desk, yes, that too tripped the RCD. Although I didn't lose any data, due to a perfect storm of incompatibility, it's been nearly two years before I found the beginnings of a replacement, a small form factor Lenovo IdeaCentre with 32 GB of RAM running Proxmox. If I was made of money, I'd probably find space for an oscilloscope and a signal generator, perhaps even a proper network analyser, but truth be told, most of my adventures these days are in the software realm. That's not to say that there is no place for such gear, just that I suspect that they'd feel overwhelming rather than something I'd grab to solve a problem. That said, regular posts by Ismo OH2FTG about resurrecting all manner of broken testing equipment revealed to me that a surprising number of these tools are essentially a computer with an operating system, running some custom application that presents itself to the user via a display. Apparently you haven't lived until you see a Windows boot loop on your Agilent oscilloscope. I suppose I shouldn't be surprised, the "HP 8920A RF Communications Test Set" that I played with a while back runs what looks like a version of DOS, which comes on ROM chips, according to HP taking 2 hours to replace for a firmware upgrade, and each of its in-built tests is a program written in HP Instrument BASIC. This morning I walked into my office and spotted my PlutoSDR on my desk. If you're unfamiliar, a PlutoSDR is a little box, blue, because of course colour matters, has two SMA coax connectors on one side and two USB sockets on the other side. One antenna port is marked "Rx", the other "Tx" and by connecting the two together, you can create a transmission and then receive it. While that sounds completely useless, it's the exact same set-up as any number of bits of test equipment, to be clear, normally you have something you're testing connected between the ports. Combine that with a connected computer and you have the makings of some fancy test gear, capable of 70 MHz to 6 GHz. Since it's all Open Source, you can write your code in your language of choice. Of course I'm not the first person to come to this point. There's tools around for making this reality, implementing oscilloscope, spectrum analyser and plenty more. I am already imagining what I might achieve with GNU Radio. While there's plenty of room for soldering irons in our community, I think it's also worth considering what software might help in your toolkit. I'm Onno VK6FLAB

Foundations of Amateur Radio Previously I've talked about using radio spectrum monitoring to detect lightning to potentially protect your equipment. This triggered an email from Nick VA3NNW, who pointed out that AM demodulation of "one point twenty-one jiggawatts", is really a red-herring, and indeed it is. Nick went on to point at another approach, which nudged things along. So, let's start with the herring, not sure about red, I prefer mine fresh, raw, and covered in finely cut raw onion. If you know, you know. If you don't, think sweet fairy-floss. For extra culinary points, pair it with fresh crusty white bread, preferably still warm from the bakery, and slather it in butter. Yum! Beats bacon any day. Oh, before I forget, pickled herring, lovely, fish aside, in terms of flavour and texture, not in anyway related to fresh herring, just so you know. Where were we, ah, uh radio. Before jumping back in, "squelch" is a radio term, it translates to "subdue forcibly", in our case, we're using it to describe a process where radio signals below a certain level, or volume if you like, are suppressed, so you'll hear nothing until the level reaches above the specified level. This is useful in all manner of scenarios where there's background noise. In amateur radio, squelch is used on VHF and UHF repeaters, but on HF it often means that weak signals don't get heard, keep that in mind next time you start diagnosing a silent radio, ask me how I know. Anyway, my initial choice of "rtl-airband" as the tool of choice for lightning detection was based on the idea that I could use it to receive a chunk of bandwidth, then automatically apply the in-built squelch to make everything silent when there was nothing but local noise, then when lightning was afoot, noise would suddenly increase above the threshold imposed by the squelch, and I could detect that. Nick pointed out that there's a better tool for this, "rtl_power", written by Kyle Keen in 2013, which can continuously monitor a whole lot more frequencies, collect them over a set period and intermittently output the power values, which can then be processed. The tool allows you to specify which frequencies to monitor, how long for and at what resolution. This is extremely useful for exploring activity on a new band. You can use the data to create images of band activity and see what's going on. I have previously used it to find intermittent interference. Note that it doesn't decode anything as such. It reports relative power levels for the spectrum you're exploring. As an aside, in the process of building a Docker container for rtl_power, because of course I did, it occurs to me that I often point at Docker as a solution, but I don't think I've ever detailed why. For starters, it allows you to install and test software without disrupting your local machine, so if you want to remove your experimental installation, you can, and nothing on your computer will be affected. It also helps with security and permissions, allowing you to define what is allowed and what isn't, helpful if you don't trust the software you're testing. It allows you to run multiple versions of the same software side-by-side, something which otherwise would create a lot of hard work and head scratching. If the software you're exploring doesn't exist on your version of operating system, there's a good chance that someone has it packaged elsewhere, Docker will allow you to use that package on your system, or you can build it from source inside the Docker container and not have all the libraries and dependencies clutter your system. There's a thing called a "Dockerfile" .. essentially a list of commands that document how something is installed. This means that you have a record on how it's done. It means that when it breaks, you have a starting point for debugging, and because it's a text file, you can version control it. Then there's the ability to automatically start a Docker container on reboot, so you don't have to futz around with "cron" or "scheduled tasks" if you're running that other operating system. If that's not enough, there's thousands of Docker images just waiting for you to try. I will mention that I tend to build my own images, but you don't need to start there. So, that's why I use Docker almost everywhere. I'd love for someone to figure out how to run Wayland applications over ssh, but I digress. Back to rtl_power. I realised that I don't yet have any data on what lightning looks like specifically. What power levels does an RTL-SDR dongle report when lighting happens, what frequencies should I monitor for the best result, how often should I check, how much data should I collate in each sample .. although we can check every second if we really want to, it seems to me that every minute or ten might be sufficient. If you have opinions, or better yet, data, to share, feel free to get in touch. I will end with a disclaimer. I have only tasted North Sea herring fresh, so you're on your own if you go fishing in a different ocean. I'm Onno VK6FLAB

Foundations of Amateur Radio In the middle of the night when insomnia rears its head, there are occasions when an idea sprouts that is still with me the next day. I imagined a spinning globe that shows ionospheric propagation and allows you to navigate around the world and experiment. Think the ionospheric equivalent of windy.com in 3D. To get to that point, I started off with the Australian Space Weather Forecasting Centre. I was on a roll when I discovered that under "HF Systems" it has a "Global HF" section with "Ionospheric Map", which, curiously enough, shows exactly what you'd expect. What surprised me was that below the map is an animation viewer that allows you to see the last three days in half hour increments. Excitedly playing with this I found myself locked out and on the phone to the Bureau of Meteorology. I suspect that someone didn't tell the people who configured their content delivery network that users might be loading a gross of images from their website in short order, or two gross, if you also look at the "T-Index Map", like I did. With no immediate solution on the horizon, I went on the hunt for other sources of maps and discovered the NASA/JPL-Caltech GUARDIAN project, described as near-real-time ionospheric monitoring software for natural hazards warning. Their website has a limited archive of daily videos showing how the ionosphere changes, which was exciting until I discovered that my computer wanted to download each one, rather than play them in the browser, so making lemonade, I downloaded all of last month, thank you "curl", used my favourite video editing tool, "ffmpeg", to combine them, then uploaded the result to my VK6FLAB YouTube channel for our enjoyment. What's fascinating to me is being able to see, for the first time, just how the ionosphere changes throughout the month. You can see where there's regular solar activity and where exceptions occur. I'll note that there's a few gaps, I suspect that the software behind the scenes at JPL had some outages, but what's there is what was available. Now for the interesting stuff. This data is not created by something monitoring in space at L1, or in orbit around Earth, it's created by ground stations scattered around the planet. GUARDIAN is based around the Global Navigation Satellite System or GNSS. The project, to give its full name, the GNSS Upper Atmospheric Real-time Disaster Information and Alert Network, uses the radio signals from the four navigation constellations, GPS, Galileo, BDS and GLONASS. Name aside, the project has some really interesting goals; objective one, the result of which you can see in the video or on the website, is to allow users to explore ionospheric perturbations, in other words, you can see how the ionosphere changes over time. This is achieved by some cool radio phenomena, specifically, two different GNSS carrier frequencies will show phase change as well as alter what's known as "pseudorange", the apparent distance between a satellite and a receiver, affected by among other things, the "Total Electron Content" or TEC along the signal path. What that means is that the satellite signal is directly and proportionally affected by what's happening in the ionosphere. As an aside, this phenomenon can impact your mobile phone navigation, more on that in a moment. In other words, if you can measure how the radio signals from a navigation satellite change, you can calculate what the ionosphere is doing along a direct line between the transmitter and receiver, in response to natural and man-made events on Earth. If that's not enough, remember, this is just the first objective, the second one is to automatically detect those changes, the third objective is to characterise potential natural hazards. Lots of words to say that the aim is to detect events like geomagnetic storms, tsunamis, earthquakes, volcanic eruptions, thunderstorms, not to mention explosions and rocket launches. You can explore some historic examples on the GUARDIAN website at JPL. You can also compare the current planetary geomagnetic index with what comes out of the GUARDIAN project. At this point you might wonder what the ionosphere has to do with tsunamis? As it turns out, a whole range of natural and man-made hazards impact the ionosphere due to significant displacements of air at the surface, and the project used historic hazards and ionospheric data to link the two, and in July 2025, the magnitude 8.8 Kamchatka earthquake and associated tsunami was automatically detected 30 minutes before it reached the coast of Hawai'i. If that doesn't hit you in the Wow spot, during my research I came across several projects that explore the use of mobile phone GPS receivers as sensors. There's billions of those, so potentially, planetary coverage. For comparison, in 2022 there were 80 Global Differential GPS ground stations powering GUARDIAN, today the network has over 200 sites. Google Research published an article in 2024 using the same methodologies to measure the ionosphere using millions of mobile phone GPS receivers, effectively doubling coverage. Their article in Nature goes into detail which devices were used and how, essentially, using anonymised and privatised Android location data. From an amateur radio perspective, it's interesting to note just how variable and dynamic the ionosphere is and what types of phenomena affect it. I also wonder if my PlutoSDR might be used to have a go, since we're talking about radio frequencies around 1.1 and 1.5 GHz. All the more reason to get on-air and make some noise and excite the ionosphere and a receiver somewhere on Earth. I'm Onno VK6FLAB

Foundations of Amateur Radio Over the weekend I had the opportunity to participate in two completely different community events, one aimed at an amateur radio audience, the other at the general public. Every year, several of the amateur radio clubs in my area hold their individual swap meet, where the aim of the event is to bring amateurs together and to use it as a social fund raising event. Some jokingly refer to it as a junk library where one person's junk is the next person's treasure, only for it to turn up on their table the next year. This particular event is held inside what can best be described as a large high school gymnasium. Mind you, my experience with high school facilities predates my amateur radio birthday by quite some decades, so, a building with a wooden floor, basket ball court and other sports markings on the floor. Mind you, this building has a canteen, a foyer and a big parking lot, so it only resembles my reminiscing in abstract ways; I grew up with bicycles and snow - from time to time, not cars and sun. Individuals and organisations can book and pay for one or more tables to display their wares. There's a raffle, growing in scope each year, the universal bloke yelling unintelligibly into a microphone, signal unreadable with an RST of 2 and 9, and there's food for sale with drinks, and tables to sit and chat. It had been a while since I'd last attended and with it came memories of setting up the local news broadcast team so we could do a live edition of the weekly amateur radio news, hard work, lots of planning and very rewarding, also good practice. This year the entry price went up, the event was down on numbers and there were half a dozen or so empty tables. I'm guessing these were booked and the participants didn't turn up, but I don't know. For the organising club this must have been heartbreaking. I know for me, it was disappointing. That said, it offered the opportunity to catch up with plenty of friends and acquaintances, new and old amateurs, people who knew me before I knew them, the typical face to face experience that you might get from accidentally being in the same place at the same time. If this description leaves you with the sense of longing, you know how I felt when I drove away to travel to the other side of the city to attend the second event. Organised by a local council as an Open Day, it brings together a bunch of different organisations to a central location, augmented with food vans, sausage sizzle, ice-cream and coffee, the whole thing was outdoors. One of the organisations represented was a different amateur radio club, based at the site, with a small display and the ability for people to talk, have a sticky beak and mosey on. Interestingly, the kids attending were given a treasure hunt sheet with questions about each of the organisations there, including two questions about the amateur radio club. Funnily enough, a local community radio station is also on site and it too had questions in the treasure hunt. This dynamic allowed kids and their parents to approach the club and ask silly questions and the confusion between "amateur" radio and "community" radio allowed for more information to be shared with more laughter to go around for all. The sausage sizzle, a local Rotary club fundraiser, was a hit with a steady stream of people lining up for a bite. This is the second time this event has been hosted and both times I spoke with many people who were not radio amateurs, people who had electronics projects in need of guidance, and the odd local politician, some more than others. Over the years I've attended plenty of amateur radio events and while there's a place and need for each of them, I have to say, talking to an interested kid about a homebrew quadrifilar helix antenna has to my favourite experience. So, why am I talking about this, you ask? It's pretty simple. Ask yourself, does a particular amateur or amateur adjacent event spark joy, or does it represent an opportunity for reflection and renewal? Do we need another swap meet, I think locally we have at least five across the year, or could you do a fundraiser with a bingo night in a pub? What about an exhibition, or an auction? A BBQ or a breakfast? A course or a camp out? Have you considered a shack open day or a school visit show and tell? What about joining forces with other community groups and clubs? What could the ultimate event bring and who would you like to see there? What would they take away and what resources might you need to pull it off? I'm Onno VK6FLAB

Foundations of Amateur Radio The other day I heard a thunderclap and as is my Pavlovian response, immediately ran to my shack to disconnect the antennas from their respective transmitter and transceiver. I added a diary entry to my phone to note that I'd disabled my WSPR, or Weak Signal Propagation Reporter beacon, which generally runs 24/7. A few hours later I remembered that my beacon was off and I returned to put it all back in working order. That's not always been the case. From time-to-time I've managed to turn off the beacon and forgotten to re-enable it, once for months. Same with my main radio, which at one point was disconnected from its antenna, taking a good half hour of stressful troubleshooting to discover one memorable Saturday morning, when I tried to set-up for my weekly net. Now it's the first step, before I turn on the power supply. I've mentioned in passing that lightning protection and grounding requirements are not globally uniform and I'm purposefully refraining from advising you how to do this in your shack. When in doubt, talk to your local community and a licensed electrician, mainly because there's plenty of poor advice around that could result in your applicable household electrical regulations being breached. Back to my shack. Wouldn't it be cool if I could automate this, something like a remote controlled relay, preferably wireless so stray RF doesn't make it into the wrong circuit. Switching aside, it occurred to me that I'd also need some way of detecting lightning to trigger this system, you know, disconnect the antennas, turn off the beacon, then reverse the process when all is clear. Speaking of automation, a few years ago I purchased a beautiful electromechanical coax switch. I'm still trying to discover how to drive it and I'm not game to power it with the risk of letting the magic smoke out, so if you have specific details for a K&L 6LMP-28-F-N-I-TTL six position coax switch, a data sheet would be wonderful, get in touch, [email protected] is my email address. Searching for lightning detectors reveals a boatload of circuits and tools. There's websites galore, an active community surrounding "blitzortung.org" with an absolutely mesmerising homepage, and plenty of other projects to play with. One thing I noticed was a distinct lack of SDR, or Software Defined Radio implementations. The number isn't zero, but I didn't find any turn-key solutions. One recurring theme, other than arguing which frequency to tune to for the best result, was the notion that a simple AM radio receiver could be used. The idea often promulgated is to tune between stations and to listen for clicks and pops. It occurred to me that using an SDR as an AM receiver is pretty much the first thing you do after plugging it in. Combining these ideas, it seems obvious, of course it's unlikely to be, but you know, why spoil the fun, to do this within the 2.6 MHz bandwidth of an RTL-SDR dongle which might actually detect some wideband RF, the signature of a lightning strike. That started me down the path of splitting a signal in GNU Radio, routing it to multiple AM decoders, looking for peaks, all that fun, when I realised that I know of a tool that does pretty much all of that, "rtl-airband". With a simple text file to describe the frequencies you want to monitor, decode, apply squelch, mix, position and route, most of the job is done. When it's running, you might have just created a lightning detector to start your journey on this road, using stuff you already have. I intend to create an example configuration file for exactly this purpose, perhaps even a script to generate it, and I'll publish it on GitHub. Word of warning, based on the number of tools alone, the rabbit hole is deep. I'm Onno VK6FLAB

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

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

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

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

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

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

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

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

Foundations of Amateur Radio It's a curious thing, this hobby of ours, in that the more you want out of it, the more challenging it becomes. For example, you might start your journey with a VHF or UHF handheld radio, sometimes referred to as a Walkie-Talkie or a Handy, and you start listening to the local repeater, or you try to make contact with a friend. Then you discover that it doesn't always work, so you learn about interference, terrain and antenna gain. You start looking for higher elevation or a better antenna and you discover that now you hear more, but you still can't talk to your friends and before long you're building filters and testing other gear and the journey continues unabated. This same incremental experience happens across every aspect of the hobby and it happens to all of us, perhaps unwitting participants on this amateur radio journey. Sometimes this experience leads to becoming discombobulated, discontented, disinterested and ultimately leads to disengagement, which in my opinion, does not need to be the case. Throughout our community we often talk about failure, as-in, a failed contact, a failed activation, a failed antenna or failed design, and on and on it goes. It occurs to me that we're not the only people who have this experience. "But the student will find that experience is the best teacher. The reason why I get along with comparative ease now is because I know from experience the enormous number of things that won't work. For instance, I start on a new invention to-morrow. From the great number of experiments I have made, and the vast amount of information I have stored up, I am saved a great deal of time and trouble in not having to travel over barren ground." If that sounds somewhat familiar, and reminds you of a quote about light-bulbs and failure, you're in good company, since those words were written in 1882 by the very same inventor of the light-bulb, Thomas Edison. In other words, the process of doing something doesn't end in failure, it's an experience, a point of learning, or if you want to be scientific about it, it's another data point. Just because something didn't go as expected, doesn't mean that it failed, just that something unexpected happened. I'm talking about this because we live in an increasingly complex world where our chosen hobby is made up from the very foundation on which we understand everything around us, the electromagnetic spectrum and all that it implies. Our adventures, frustrating as we might find them, are built upon the shoulders of giants who became silent keys long before our parents walked this Earth. Your participation, little by little, increases our global knowledge, experience and understanding and when something unexpected happens, it's time to celebrate, rather than give up in disgust. I've only been playing with radios for a short time, especially when I compare it with my experience in other areas of technology, but I can say, that framing matters. "Failure" is, in my experience, regularly thought of in a negative light and all too often it leads people to stop playing, because who really derives joy from banging your head against a wall? So, next time, when you're about to use that dreaded F-word, consider what might happen if you thought of it as a piece of experience earned instead? I'm Onno VK6FLAB