The other day Randall, VK6WR, encouraged me to get on-air. He described it like this:

"There is a mystery signal on 40m that you can try your new Universal Radio Hacker skills on. It appears to be a FSK signal separated by 7kHz with the two signals at 7.0615 and 7.0685 MHz. Each of them on their own sounds a bit like a Morse signal, but my CW decoder decodes junk. But if you can see it on a spectrum scope, it is clearly FSK because either one of them is on at any time."

He went on to say: "You'll need an SDR to receive the signal given the separation, but could be a fun investigation!"

Having just discovered "Universal Radio Hacker", a tool that can help you decode radio signals, that sounded like something I'd love to have a go at. Unfortunately, after the demise of my main workstation last year, my current set-up doesn't allow me to do such recordings, but Randall, ever the gentleman, provided a recording of the signal.

He writes: "This was captured with gqrx demodulating the signal as SSB audio with the VFO tuned to 7.060, so both "signals" are there, one very low freq and one very high freq."

If you're curious, I've uploaded the file as it was shared with me to my VK6FLAB GitHub repository under "signals".

Over the next two days I spent my time attempting to decode this signal. I opened up Universal Radio Hacker and spent delightful hours getting precisely .. nowhere. Some of that is absolutely my unfamiliarity with the tool, but this is a great exercise in learning on the fly, where truth be told, I tend to live most of my life.

It wasn't until several hours later that I decided I should at least listen to the audio. To my ear it sounded like 25 WPM Morse Code, but being still in the learning phases, while my brain was triggering on the sequences, decoding wasn't happening. Of course I could cheat and forward the audio to one of my fellow amateurs, but the actual message wasn't really the point of the exercise, at least not at this stage.

Instead I fired up "multimon-ng" which has an in-built Morse decoder. I spent some hours doing more Yak Shaving than I was expecting, but even then, I still didn't get more than gobbledegook out of the process. I used "Audacity" to shift one of the signals by one wavelength and mixed them together. This allowed me to reduce the noise significantly, but still none of my tools did anything useful. In case you're wondering why, if you have a tone and noise and shift one signal by the wavelength of the tone, then mix them, the tone adds to itself, but the noise, random in nature, is just as likely to add as it is to subtract, so in effect, you're increased the signal to noise ratio.

After multimon-ng failed, I tried an online Morse decoder, which gave me all manner of text, but none of it made sense to me. Of course it's possible that this is someone rag chewing in a different language, but I couldn't make any sense of the thing.

I did come up with some issues that prompted me to create the signal repository. I realised that I didn't have any known "good" signals. Previously I'd tried decoding a sample FT4 signal, but that went nowhere, mainly because the signal was noisy.

So, what I'm going to do over the next couple of weeks is create some clean, as-in, computer generated, known signals, and add them to the repository. The aim is to have a known good starting point to learn from. In software development this technique is often used to limit the number of unconstrained variables. In our case, if I generate a known good Morse Code signal, then I can learn how to use Universal Radio Hacker to decode it, so when I come across an unknown signal, I can use the techniques I learnt to attempt to decode it.

Feel free to make pull requests with known good signals yourself. RTTY, PSK31, WSPR, FT8, etc. Feel free to include non-amateur modes.

One thing, I'm not looking for off-air recordings of signals, yet, that can come later, right now I need signals that are pure, as-in, as I said, computer generated. Of course at some point, perhaps sooner rather than later, I'll discover that generated signals are no easier to decode than off-air recordings, but that's for another day.

Meanwhile, you too can play. Download one or more sample files and decode them. Let me know what you learn.

I'm Onno VK6FLAB

The other day I was discussing with a fellow amateur the increased frustration my mobile phone provider was inflicting. We hit on the idea of figuring out if other providers would fit the bill and how we could determine if their coverage would suit our needs. Aside from using an old mobile phone, I suggested that using a $25 RTL-SDR dongle would provide a way to record mobile phone cell site beacons from the various mobile networks to map what signal levels we might find.

To that end, I discovered a tool called LTE-Cell-Scanner by Xianjun BH1RXH. Forked from the original project by James Peroulas, it allows you to use simple hardware to scan for LTE Cells used by mobile phone networks. James points out on his site that this tool can also be used to calibrate an RTL-SDR receiver's oscillator, since an LTE downlink centre frequency is stable to within 50 Parts Per Billion, that's 10 times more stable than my Yaesu FT-857d using a TCXO.

If this doesn't mean much, think of it as a local frequency reference standard that you can use in your shack with minimal effort and cost.

The story gets better.

I started building LTE-Cell-Scanner from source and in doing so discovered a directory on my computer named "uhrr". I didn't remember what it was for, so I looked online. The first search result, when I looked for "uhrr radio" was a repository by Oliver F4HTB, more on that in a bit.

The second search result was something called "Universal Radio Hacker". I clicked on the link and discovered a mind boggling tool. There are times in your life when something flips, this was one of those times. It happened when I discovered "csdr" by Andras HA7ILM and again when I discovered "GNU Radio".

Diving into "Universal Radio Hacker", by Dr. Johannes Pohl and Dr. Andreas Noack I was introduced to the art of decoding and generating digital radio signals. In 2018 it was presented for the first time during the USENIX Workshop on Offensive Technologies, or WOOT, as a tool to discover, decode and identify exploits of proprietary IoT devices scattered all over the planet. As an aside, USENIX, Users Of Unix, since 1975.

Back to radio. Universal Radio Hacker allows you to dissect recorded radio signals using all manner of interactive processes. When you go looking for it, and you should, I recommend that you start by watching some videos. You'll find an introductory play list on my YouTube channel. By the time you've seen those, you'll likely share my excitement.

To encourage you further, the Universal Radio Hacker is open source, written in Python, and runs on Linux, MacOS and Windows. So far there have been 94 releases of the software, so it's seen significant development in the years since it was released into the wild.

When installing it I was surprised to discover that its acronym was "uhr", not "uhrr". This was a relief since I still didn't remember what "uhrr" was all about and I couldn't imagine having forgotten Universal Radio Hacker. It turns out that the last time I looked at "uhrr" was apparently in 2021 when I shared my experience in an article titled "The remote edge..."; "uhrr" or "Universal Ham Radio Remote" is a tool that allows you to use a web browser to access a radio remotely.

My little journey into unexpected diversions, distractions and discovery has led me into a path where several puzzle pieces have come together. For example, Universal Radio Hacker and GNU Radio can talk to each other, they're both written in Python, they're both open source, have a history of development and have a community of users. The LTE-Cell-Scanner, also open source, will allow me to calibrate most if not all of my radio gear and I'm once again inspired to keep digging into yet another aspect of this wonderful hobby. I'm sure that there are more than a thousand different hobbies under this roof.

Go forth, explore, discover, be amazed, and stay curious!

I'm Onno VK6FLAB

The other day a fellow amateur asked me to help them with lowering their radio mast so they could do some maintenance on the antennas attached to it. This is not the first time I've been a participant in such an activity, but it was the first time I felt explicitly safe.

Don't get me wrong, on previous occasions nothing bad happened, but there was always an undertone of "what-if" and an associated anxiety. This time was different. Before we did anything, we sat down, had a cup of coffee, talked and discussed what was going to happen. After coffee we looked at specifics and discussed the process in detail. Then we prepared. Clipping cable ties, winding up loose ends, disconnecting coax, and securing a pulley to a tree. We ran a winch line, discussed distances, looked at potential snags and coax lengths and angles, considered what would happen if something unexpected might happen and discussed various safety considerations, like never walking below the mast whilst it was in its most stressed position, half-way lowered and out of reach.

Then we slowly went about doing what we talked about.

All that sounds pretty reasonable, and it should. It was the first time I'd ever discussed in detail what the plan was, what could happen if something broke, if something got caught and any number of contingencies. We even discussed handling steel winch lines, something which I was unfamiliar with.

Of course it's entirely possible that something bad could happen, something neither of us had considered, but we put ourselves in a position where we both felt safe after mitigating known risks and allowing leeway for unknown risks.

Another word for this type of preparation is "Professionalism". It's a fraught word. You might recall me telling a story where I contacted the regulator to discuss wideband interference caused by a train-line, specifically blocking out a range of AM broadcast frequencies, including the emergency broadcast station. I revealed during that conversation that I was an amateur and had some experience with radio. The person I was speaking to shared that they were a "Professional", using a capital "P" to condescend that my amateur credentials were nothing in comparison to theirs. The conversation ended, the wideband interference is still there, years later.

It's not the only time I've come across this weird relationship with this word "Professionalism". At one time I worked at a community broadcaster where I was one of the producers and presenters. If you're unfamiliar, it's essentially a special interest broadcaster, in this case radio, run by mostly volunteers. We were having a meeting to discuss plans and during that I raised the notion of "Professionalism" in relation to conduct, things like turning up on time for your shift, documenting labels correctly on tapes, keeping logs, broadcasting advertisements at the allocated time, etc. Unfortunately some in the group equated "Professionalism" with "Commercialism" and expressed their discontent with the notion vocally. I stopped volunteering there shortly after.

This to say that I can understand that "Professionalism" has different meanings for different people. In a community like Amateur Radio it might mean that it's considered a taboo word, but I'd like to encourage you to think of it as a way of getting things done .. safely .. and to the betterment of the community.

So, next time you have a working bee, an antenna party, a contest, or a ham-fest, think about how you conduct yourself, how you might improve the experience for yourself and for those around you.

I call that "Professionalism".

I'm Onno VK6FLAB

Right off the bat, let me start with a question. "What do you think you're doing?"

To give you some context, it should come as no surprise that I'm talking about amateur radio and what it is that we do, you and I, when we "do amateur radio".

Of course the answer is different for every person you ask, and it's likely to change over time. So, let's explore and fair warning, if you know me at all, you'll realise that I'll be asking more questions, so here goes.

Is this an activity that you do, for yourself, or for others? Is it a hobby, or a vocation, or something else? Do you use this as part of your life outside this community and if you do, how?

At this point I hope you're getting a sense of Deja-Vu all over again, in that I'm asking you to explore your own place in the community. I'm asking because it occurs to me that we spend an awful lot of time looking in the other direction.

How do we compare skills and knowledge against other amateurs, how does our shack compare with another, how does our antenna stack up, which modes have you used, what things have you activated, how much power do you use? All things that might form part of the activity of amateur radio, but fail to look at you as a person and your role in this.

For example, have you considered if you're interested in helping new amateurs, or would you rather just do your own thing? What about how you gain skills? Would you rather read a book, watch a YouTube video, attend a class or play with others? If you're considering upgrading your license to gain more responsibilities, are you doing that for yourself, or are you doing it because of peer pressure?

If you've been part of the hobby for a little while you'll have discovered that radio amateurs are everywhere, often in unexpected places. With that comes the realisation that this implies that we have members who represent all of humanity in all its many-splendored complexity. Where in that spectrum are you and what is your role in participating in that wider community, and is your role what you want it to be?

One of the themes I've discovered over the years is insecurity. A recurring perception is that amateurs who've attained the highest license level are somehow "more" amateur than those who are on another journey. Where do you fit in that? How do you perceive amateurs with differing license classes? Do you apply the same metric to moped, car and truck licenses? How do you compare yourself against those who are not amateurs and how did you step into your license?

I'm going to stop with the questions now and leave you with a thought.

The hobby of amateur radio is a playground where you have the freedom to explore radio and all that it offers, but nobody said that you need to limit yourself to radio.

I'm Onno VK6FLAB

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

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

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

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

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

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

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

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

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

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

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

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

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

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

I'm Onno VK6FLAB