vk6flab

One of the basic aspects of being human and growing up is the process of learning. From a young age we explore our environment, play with others, have fun, fall over and bruise our knees, get up and try again. The playing aspect of this is often discussed as a way to keep things interesting. We add a competition element as an added incentive, so much so that we formaulate it into global competitions and call it sport.

As a species it might surprise you that we spend about 1% of all Gross Domestic Product on sport, compared to science, which is about 2% of Global GDP. To give you some context, Agriculture accounts for about 4%, Manufacturing is 15%, Industry is about 26%, and Services account for roughly 62%. If you noticed that this is more than 100%, take it up with the World Bank, I'm a radio amateur, not an economist.

Over the years I've explored different aspects of our chosen hobby of amateur radio. Time and again I return to experimentation, learning and having fun. Now I absolutely concede that my idea of fun and yours might not match, my GDP side quest is likely evidence of this, but in my opinion, this embodies the range of how we as a disparate community interact and exchange ideas across the ionosphere and closer to home using what we all can agree on is pretty close to magic.

So, what is my point? Fair question. Having fun and learning.

If you've ever had the opportunity to listen to aviation radio, and I'd encourage you to, the YouTube channel, VASAviation is a great place to start, comes with maps, explanations and subtitles. You'll discover that the complex domain of aviation communication is a dynamic environment where miscommunication matters and often has severe consequences. It's not all incidents and accidents though. If you look for Air Traffic Control legend "Kennedy Steve", you'll come across some of the funniest exchanges captured on ATC frequencies, all the while staying professional.

So, how does this relate to amateur radio and you?

Well, at the moment we have a few types of exchanges where we can practice our skills. The most obvious one is a thing we call contesting. A scored and rule bound activity where you're expected to exchange information and are declared the winner in a category. It's a little like sport and some have attempted to rephrase amateur radio contesting into a field that they're calling "radio sport". I have mixed feelings about this because there isn't much in the way of spectator activity associated with this.

Another exchange is calling for DX contacts, sharing an exchange across distance, attempting to contact as many countries as possible, with the prize being membership into the fabled DXCC, the Century Club that acknowledges your prowess in making contact with a hundred countries.

The most common exchange is the net or discussion group. It can be formal, like the weekly F-troop I've been hosting since 2011, or it can be ad hoc, one amateur chatting to another, sparking spontaneous discussion among several stations on frequency.

We also do things like radio direction finding, someone sets up a transmitter and everyone playing tries to find the source as quickly as possible. First one to find it wins.

It made me wonder if there are other things we might come up with.

Has anyone played chess across HF? Or if you want to involve a larger group, what about playing Bingo! or a game of trivia? Anyone considered an MMORPG, or Massively Multiplayer Online Role Playing Game?

The point being that we can play games, have fun, and learn in an environment where there are many factors affecting your ability to communicate, so we can all get better at keying the microphone and getting the message to the intended recipient.

While we're having fun, nobody said that this needs to be a voice activity. An FT8 session could well be coerced into transmitting chess moves and nobody said that you have to do FT8 on the same frequency that WSJT-X is using.

So, what games can you come up with and learn from?

I'm Onno VK6FLAB

When you join the community of radio amateurs, or when you briefly look over the shoulder of the nearest devotee, you're likely to discover that this is a hobby about a great many different ideas. Over the years I've discussed this aspect of our community repeatedly, talked about the rewards it brings you, about the camaraderie, about communication, learning, research, soldering, disaster recovery, public service, and all the other thousands of activities that this hobby represents to the world.

While all those things might be true for some, they're not true for everyone. Many amateurs get excited about antennas, some immediately, some eventually. The same can be said for all the other points of what we think of when we discuss our hobby with others.

Recently I saw a random comment on social media from a person who was having issues with their mobile phone on their property. I considered and ventured an opinion about what might be the cause and how they might go about discovering what was going on.

I debated about how I signed off. It's a recurring dialogue, should I reveal upfront that I'm a radio amateur, or should I leave that to be discovered at a later date? In my experience, the wider society has a, let's call it a rocky relationship with our hobby. With the decrease in profile and numbers comes an increase in misconception about who it is that we are, and what it is that we do.

At some level, there's an understanding that at some point this was an activity that grandpa might have engaged in, or it might be someone preparing for the end of the world, seeing our community as the way forward when all else fails, not at all helped by that slogan being used by a vocal amateur radio body, the ARRL.

Given that, as I saw it, the issue was related to radio interference or a weak signal, I signed off, for better or worse, "Source: I'm a licensed radio amateur", and crossed my fingers.

This started a discussion about the issue, which revealed that the person was having other problems with other communication tools in their remote village. I don't want to go into the specifics, because it's not about what their issue is, where they live and what other resources they might have access to, or not. It's about us, radio amateurs, because of course it is.

Aside from the cringe associated with my sign-off, if you have suggestions on how to improve it, I'm all ears, I had a take-away that I thought was worth discussing. As I'm beginning to suspect, it's about the fundamental nature of our hobby, what it is and what it does.

Troubleshooting.

Let me say that again. Amateur Radio is fundamentally about "troubleshooting", in other words, systematically finding and fixing complex problems.

So, let's explore this.

If you consider we're all about communication in difficult environments, I'd point out that getting that message across is an exercise in troubleshooting.

If you lean towards learning, then consider deciding what to study and why, more troubleshooting.

If you suggest it's about soldering, what happens when you poke the leg of a component into the wrong hole? Do I really need to say it?

Every time you think you've nailed down the intangible nature of our hobby, you can point at troubleshooting. Don't get me wrong, it's about having fun too, but you and I both know that fun is balanced by frustration, again, you guessed it, troubleshooting.

In our increasingly technical, interconnected and complex world, the ancient pursuit of amateur radio is teaching you an invaluable skill, over and over again, all but inevitably: "The art of troubleshooting".

So, next time you are asked why we should be doing this thing, why we are obsessed with this hobby, why we spend many hours, dollars and effort, it's all about finding out why something doesn't work as expected and funnily enough, the more you do it, the better you get.

For radio amateurs, troubleshooting is our superpower.

I'm Onno VK6FLAB

You can't wear one leg each from two different pairs of jeans and go about your daily business, like you could for two pairs of shoes or socks, each of which is independent from the other, albeit left and right specific in various cases.

The same is true for a pair of reading glasses.

Whilst it's obvious that both glasses and jeans (and pants in general) are referred to as being a pair, due to the two legs and eyes aspect, we don't refer to a jumper as a pair of jumpers, unless there's physically four sleeves attached to two bodies.

Why is that and where else does this occur?

Death is inevitable but we still seem flummoxed by it happening. We have all kinds of End of Life policies and procedures which do everything possible to make life difficult for those left behind.

Our language is around loss and unexpected, and grief and being bereft.

Why do we make Death so hard to process in our community and what can we do to normalise it across society?

Recently I started an experiment I plan to run for a year. Using a WSPR beacon and a dummy load I'm transmitting 200 mW, 24 hours a day across all bands supported by my hardware, in this case it covers 80m, 40m, 30m, 20m, 17m, 15m, 12m, and 10m. The aim of the experiment is to determine if, and to what extent my dummy load can be heard outside my shack. Why? Because I've not seen anyone do this and because a dummy load is widely believed to not radiate, despite evidence to the contrary.

Together with the transmission side, I've also configured an RTL-SDR dongle, initially with the telescopic antenna it came with, now, since my HF antenna isn't being used by the beacon, I'm using it instead. It's about five metres away from the beacon, outside. It's a helically wound whip resonant on the 40m band built by Walter VK6BCP (SK). It's what I've been using as my main antenna for the past seven years or so.

While I'm telling you this, my beacon has been heard by my dongle 1,182 times across all eight bands. Some of those reports were from inside the shack, some from outside, some while I was monitoring a single band, and for the past week or so, I've been monitoring all the bands supported by "rtlsdr_wsprd", 18 in all. Purposefully, this includes some bands that I'm not transmitting on, because who knows what kinds of harmonics I might discover? The receiver changes band every half hour, so over time when I monitor a band will shift across the day, this is deliberate. I don't know when a stray transmission might suddenly appear and this will give me the best chance of hearing it, short of using 18 different receivers.

At this time, my beacon hasn't been heard by any other station. I'm not expecting it to, but that's why I'm doing this experiment in the first place.

I'm not in any way reaching any sense of "DX on a dummy load", but it got me thinking. My beacon can be heard, albeit by me, from five meters away. So it's radiating to some extent. I've already discussed that this might come from the patch lead between the beacon and the dummy load, or it could be the dummy load itself, or some other aspect of the testing configuration. Regardless of the situation, there is a signal coming from my beacon that's wirelessly being heard by a receiver.

That's the same as what you'd hope to achieve with any antenna.

So, in what way are an antenna and a dummy load different, and in what way are they the same?

Whenever someone asks this, the stock answer is that an antenna radiates and a dummy load doesn't. My experiment, 20 days in, has already proven that this distinction is incomplete, if not outright wrong.

Even so, if we take it on face value, and we say, for argument's sake, that a dummy load doesn't radiate and an antenna does, then how do we materially distinguish between the two? How does an antenna compare to a dipole, Yagi or vertical antenna and where does the isotropic radiator fit in this?

The best I've come up with so far is a spectrum line comparing the various elements. Let's say that at one end of the spectrum is a dummy load, at the other is an isotropic radiator, to refresh your memory, that's the ideal radiator, it radiates all RF energy in all directions equally.

Somewhere between the two ends is a dipole. We might argue if the dipole sits equally between a dummy load and an isotropic radiator, but where does a Yagi or a vertical fit in relation to the dipole?

Also, if you turn a Yagi in the other direction, does it change place?

So, perfect this notion is not, but here's my question.

What's the measurement along the axis between the dummy load and the isotropic radiator? It's not SWR, since the ideal antenna and a dummy load share the same SWR, unless this line is a circle that I don't know about. It might be Total Radiated Power expressed in Watts, but that seems counter intuitive. It would mean that in order to determine the effectiveness of an antenna we'd need to set-up in an anechoic chamber, basically a warehouse sized room where incoming radiation is shielded to some predetermined standard.

Do we measure gain using a VNA and call it a day, or is there something else going on? Remember, we're attempting to quantify the difference between a dummy load and an antenna.

In case you're wondering, I'm asking the question.

In the 15 years I've been part of this community, I've never seen any coherent response. The Internet seems to return a variation on the radiation vs. not-radiation pattern, but so far I've not seen anyone quantify this, or perhaps I haven't understood it while it was staring me in the face. I even checked the syllabus for the three license classes in Australia. The single reference that the regulator appears to specify is that at the introductory level you are required to, wait for it, recall that when testing a transmitter, a non-radiating load, or dummy load, is commonly used to prevent a signal from being radiated.

Very illuminating. Obviously my dummy load is of the wrong type, the radiating variety. Which begs the question, if there's an ideal radiator, is there a theoretical ideal dummy load that doesn't radiate in any way, and if so, how far away on this line is it from my actual dummy load?

Over to you. What are your thoughts on this? Better yet, got any references?

I'm Onno VK6FLAB

Recently Glynn VK6PAW and I had the opportunity to play radio. This isn't something that happens often so we try to make the most of it. For our efforts we had plenty of frustrations, to the point where we were joking that I should rename this to "Frustrations of Amateur Radio".

That was until we heard something weird on-air. All setup shenanigans forgotten, we marvelled at the experience.

I was playing around on the 10m band, trying to hear people making noise and potentially our first contact for the field day we were participating in, when I heard something odd. Two stations talking to each other, but the audio was strange. It was like they were doubling up, the same audio played a fraction of a second later, until that moment, something I've only ever heard in a radio studio whilst editing using a reel-to-reel tape machine with separate recording and playback heads.

Having just started using a digital only radio, at first I thought this was an artefact of the radio. I took note of the frequency, 28.460 MHz and told Glynn about it. After we moved the telescopic vertical antenna to the analogue radio, we discovered that this was in fact real, not caused by the radios, no doubt a relief to the proud owner of both radios, Glynn, who was thinking more clearly than I. He took note of the callsigns, Dom VK2HJ and Yukiharu JE1CSW. Looking back now, an audio recording would have been helpful.

At the time I suggested that this might be a case of long path and short path signals arriving at our station and being able to hear both. If you're not sure what that means, when you transmit, an antenna essentially radiates in all directions and signals travel all over the globe. Some head directly towards your destination, the short path, others head in exactly the opposite direction, taking the long way around Earth, the long path.

You might think that the majority of contacts are made using the short path, but it regularly happens the other way around, where the long path is heard and the short path is not. As you might know, radio waves essentially bounce up and down between the ionosphere and Earth and it might happen that the signal arrives at the destination antenna, or it might happen that it bounces right over the top, making either short path or long path heard, or not.

In this case, both arrived clearly audible.

It wasn't until I sat down on the couch afterwards with a calculator that I was able to at least prove to my own satisfaction that this is what we heard.

So, what were those calculations and what was the delay?

The circumference of Earth is roughly 40,000 km. RF propagation travels at the speed of light, or about 300,000 km/s. It takes about 0.13 seconds or 130 milliseconds for a radio signal to travel around Earth.

At this point you might realise that 40,000 km is measured at the surface, but ionospheric propagation happens in the ionosphere, making the circumference at the very top of the ionosphere about 45,000 km, which would take 150 ms.

There are several things that need to line up for this all to work.

Propagation aside, the distance between all three stations needs to be such that the number of hops between each combination is a whole number so we can all hear each other.

As it happens, the distance between Perth in Western Australia and Maebashi City in Japan is pretty close to the distance between Goulburn in New South Wales and Japan, and the distance between Goulburn and Perth is roughly half that.

Using back of napkin trigonometry, it appears that 27 hops around the planet are required to make this happen. That's five hops between Perth and Japan, and between Goulburn and Japan, and two hops between Goulburn and Perth, and 27 hops between Perth and Japan the long way around.

Given that the F2 layer where the 10m signal is refracted exists between about 220 km and 800 km, we can estimate that the total delay for the long path is at least 144 ms.

That doesn't really translate into anything you might relate to, but at 8 wpm a Morse code dit takes 150 milliseconds, which gives you a sense of how long the echo delay is. In other words, it's something that you can absolutely hear without needing to measure it.

There are other implications.

WSPR signals are used to test weak signal propagation. Stations around the globe report on what they can hear and when. For this to work, the signal need to be synchronised, something which is commonly implemented using something called NTP, or Network Time Protocol. It can achieve a time accuracy of 10 ms. GPS locked WSPR beacons can achieve an accuracy of 40 nanoseconds.

In other words, if we know that the beacon and the receiver are time synchronised, we can probably detect if the signal arrived using a short path or a long path. The WSPR decoder tracks the time between when the signal arrived and 2 seconds past an even minute as perceived by the receiver. Gwyn G3ZIL wrote an interesting document called "Timescale wsprdaemon database queries V2" on the subject of the data format used by wsprdaemon, a tool used to analyse WSPR beacon transmissions. If this is something you want to play with, check out wsprdaemon.org

From our adventures there was plenty to take away. Stay curious, go portable, take notes, practice putting up an antenna, keep a log, laugh and have fun, and last but not least, get on air and make noise.

Before I forget, make sure your mate brings a pen for logging when your own trusty scribble stick suddenly gives up the ghost for no apparent reason. I knew there was a reason I prefer pencils.

I'm Onno VK6FLAB

cross-posted from: https://infosec.pub/post/25342439

cross-posted from: https://lemmy.radio/post/6473282

One of our fellow amateurs needs help to recover their Google account. They have the credentials, but no longer have access to their recovery phone number.

Does anyone have any suggestions on how to proceed? My Google-fu is only unearthing unhelpful forum posts without any firm process described by Google.

Anyone have any links or contacts?

One of our fellow amateurs needs help to recover their Google account. They have the credentials, but no longer have access to their recovery phone number.

Does anyone have any suggestions on how to proceed? My Google-fu is only unearthing unhelpful forum posts without any firm process described by Google.

Anyone have any links or contacts?

Recently I received a question in relation to the Bald Yak project. If you're not familiar, "The Bald Yak project aims to create a modular, bidirectional and distributed signal processing and control system that leverages GNU Radio."

I know that I've said that several times now and I suspect I'm going to say it several more times before we're done. I was asked about a specific radio and if this project could make it use a frequency that the supplied software didn't cover.

The answer is deceptively simple and if you know me at all, you know what's coming: "It depends". As with many things, what it depends on is not fixed. I'll come back to the question, but I'm making a diversion past a magical place, the local hardware store. You can buy everything you need to build a house with the caveat that some assembly is required. GNU Radio is similar for building a signal processing system, but, wait for it, some assembly is required.

In the context of GNU Radio this means that you'll need to collect all the bits and wire them together, fortunately you're unlikely to need Personal Protective Equipment or access to a First Aid Kit, unless of course the idea of playing with computers gives you palpitations, in which case I'd recommend that you go see your doctor.

One of the less obvious things you'll come across with GNU Radio is how to bring signal processing into the physical realm, in other words, how do you get a signal into your computer, known as a "source", and get it out, called a "sink".

The ability to talk to physical hardware arrives in roughly three different ways. Let's call them, "native", "library", and "abstraction". Native access requires that GNU Radio already knows about the hardware out of the box. Library access requires that the hardware manufacturer has provided software libraries, also known as drivers, allowing GNU Radio to communicate, and finally, abstraction is where a third party has written a library that knows how to talk to hardware from different manufacturers.

The distinction between these is almost arbitrary, for example abstraction might require a driver from a hardware manufacturer. Similarly, because all this software is open source, native can include software from other projects, like the RTL-SDR blocks from Osmocom, Open Source Mobile Communications, and UHD blocks written by Ettus Research, which in turn can be seen as an abstraction.

As I said, some assembly required.

I will point out that this provides a great deal of flexibility, albeit at the cost of complexity, there's still no such thing as a free lunch.

At this point you might shake your head and run away. I get that, it can be daunting. Before you do, consider the scenario where you have a working system and you upgrade your hardware. In a GNU Radio world you'll need to figure out how to configure the new hardware and then all your other stuff will continue to work.

The alternative is upgrading each of your applications to connect to your new radio and in doing so, run the risk of making your old radio obsolete, even if you are collecting them .. let's say for posterity rather than hoarding .. because radio amateurs never hoard anything .. right?

Back to the original question. Can GNU Radio make a radio use frequencies that the software that came with the radio cannot? As I said, "it depends".

First of all, the hardware needs to actually be able to support the frequency. Then someone needs to have written a library to use that frequency, then GNU Radio needs to be able to use that library.

That said, the chances of that happening are much higher than the chance of the hardware manufacturer rolling out this feature within your lifetime. Before you start yelling at me, yes, this is manufacturer dependent, some provide open source tools, many still don't.

There are alternative ways to access different frequencies.

The PlutoSDR is a computer and radio in a box. You can connect to it, change some settings and have it access a whole lot more frequencies. In some ways it's like adding or removing jumpers on a traditional circuit-board.

Another approach is to use an up- or down-converter. Essentially a piece of hardware connected between antenna and radio that translates frequencies to different bands. A down-converter allows you to use the 23cm band on a radio that's only capable of 70cm. Similarly, an up-converter allows your 70cm radio to hear HF signals. If you see a symmetry here, you didn't imagine it. You need both to transmit and receive, sold together in the same box as a transverter.

Just so we're clear, the radio is still using the 70cm band, but the RF coming in and out of the antenna connected to the transverter is on a different band entirely. It's why my Yaesu FT-857d has three menu options, 89, 90 and 91, to adjust the display to show the actual RF frequency. As an aside, you could use this functionality if your radio is off frequency by a known amount.

As I've said before, GNU Radio is a powerful tool. It contains many different moving parts, the system is complex and unwieldy, but with it comes the promise of doing some amazing stuff.

The whole point of the Bald Yak project is to make this all accessible to the wider amateur community, not just computer geeks and software radio nerds.

If you have questions, feel free to drop me a line.

I'm Onno VK6FLAB

Update:

https://darkmentor.com/blog/esp32_non-backdoor/