Over the past nine months or so I've been working on a project that I've called Bald Yak. 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.

One of the, admittedly many, challenges I've set myself is getting data from a radio receiver into GNU Radio across the network, preferably the Internet. Today I can report a small step in the right direction and frankly I can't contain my excitement.

Now, I need to acknowledge that I'm geeking out here. It's hard to contain excitement when you find something that seems to speak your language. It also means that I realise that I run the very real risk that I'm going to lose you before you get to why this is a milestone, so let's put that up front before I explain why.

To whet your appetite, yes, you can access a KiwiSDR across the Internet and record raw data from it and control the process externally. This is a very big chunk of the problem I've been working on and turns out to actually be live and ready to play with.

Fair warning this is technical, there are moving parts. I'll do my best to explain, but if I miss any, feel free to get in touch, you have my address, cq@vk6flab.com.

In passing, recently I made mention of the KiwiSDR community and tools that could potentially allow access to a remote receiver, although at the time I pointed out that I wasn't sure if the tools I found could access remote receivers, or if they were intended to access hardware locally.

KiwiSDR is one of a group of so-called Web SDR tools. Essentially a website where you can access a remote receiver and tune to the radio signals it can hear. SDR, or software defined radio, is a way to convert incoming antenna signals into the digital realm where computers, and in this case, the Internet, live.

Turns out that a tool called "KiwiClient" takes a hostname and a port as a parameter, so much so that the in-built help shows this as the first example. What this means is that you can essentially run a copy of KiwiClient on your own computer and use it to access a KiwiSDR across the Internet.

The first commit was on the 8th of May 2017 and thanks to the efforts of about 14 developers, KiwiClient is the software equivalent of a KiwiSDR multi-tool. This is exciting all by itself, but this gets better.

You can specify more than one server. This means that you can record two, or more, signals from across the globe, and capture these simultaneously.

You can set the decode mode, which I immediately used to tune to a local broadcast station and recorded it from two different receivers across the Internet, allowing me to not only compare the difference in delay between the signals, but also the reception differences. It's fascinating to hear the same station from two receivers, one in each ear, all manner of different propagation artefacts become apparent.

Then I got a little more adventurous and discovered that one of the supported modes is I/Q, which means that I can, and did, download raw sample data across the network, which can then be used within GNU Radio. This is important because the aim for Bald Yak is to process the signals separately from the receiver.

It gets better.

There is a radio fax receiver that automatically saves pages as they are processed, something that you could use to access weather fax services.

Then there's a tool you can link to "WSJT-X", which you might recall is an application that can decode weak signals. Not only that, the tool supports "fldigi", a digital radio mode application. Both those applications can control the radio using Hamlib rigctl, which means that KiwiClient supports changing frequencies of the receiver, across the Internet, though truth be told, I haven't yet tested that .. my available computing resources are still strictly limited.

Oh, the software also has the ability to record waterfalls, do scanning, and provides tools to analyse waterfalls in jupyter notebooks.

Getting this to work wasn't too hard. The instructions on the KiwiClient GitHub repository are pretty good. I've made an initial Dockerfile on my own GitHub repository to download and install the software. It's unimaginatively called "kiwiclient-on-docker". I've yet to discover a good way to add or update Dockerfile functionality to existing projects, feel free to make suggestions.

Now I absolutely understand that this level of excitement might not universally translate and that's fine. It's yet another example of how rich and diverse our amateur radio community really is.

What gets your excitement levels going?

I'm Onno VK6FLAB

The other day I stumbled on a random post by Gary N8DMT which caused me to view the world in a different way. The post outlined combining a PlutoSDR and an application called SATSAGEN to measure the frequency characteristics of a coupler.

Aside from a detailed description, the post includes a couple of excellent photos showing the PlutoSDR connected to the coupler and the output piped back into the Pluto.

Before I continue, a PlutoSDR is a Software Defined Radio or SDR, officially it's called the ADALM Pluto Software Defined Radio Active Learning Module. It's essentially a full-duplex radio and computer in a box. It runs Linux and connects to the world via USB, and of course radio, unofficially between 70 MHz and 6 GHz. I've talked about this device before. When I say full-duplex, I mean that it can transmit and receive at the same time.

Gary's post triggered something unexpected in me. The notion that you could use two patch leads, one connected to the transmitter, the other connected to the receiver, joined together by a device that you might want to test.

It immediately reminded me of another device that was given to me, a NanoVNA, a device that's specifically designed to measure things like impedance, frequency response, generate Smith charts and all manner of other characteristics.

Not only that, it also reminded me of another device, a TinySA, specifically designed to analyse spectrum and to generate signals.

Both the NanoVNA and TinySA are lovely tools, but in looking at the post it suddenly occurred to me that their functionality, at least superficially, appears to mirror the PlutoSDR, in that you can create a signal and then measure that signal.

Turns out that I'm not the first to make this observation. For example, the YouTube channel "From Concept To Circuit" goes through the process of describing precisely the concepts behind both a spectrum analyser and a network analyser while showing the programming code in Python. The channel also provides that code in a GitHub repository, which includes several other very interesting examples, like a beamforming transmitter as well as a beamforming receiver, also covered on YouTube.

Another example is a tool I already mentioned, SATSAGEN, by Alberto IU1KVL, which implements a wideband spectrum analyser. Although it's Windows only, Alberto includes information on how to run it using Wine under Linux and MacOS. As a bonus, SATSAGEN in addition to the PlutoSDR, also supports RTL-SDR dongles, HackRF, USRP, RSP1, AirSpy, and many others.

If text is more your thing, "retrogram-plutosdr", shows a spectrogram in your terminal window. Check out the "r4d10n" GitHub repository belonging to Rakesh VU3RGP, who says that the "retrogram" project is "hacked from" the "RX ASCII Art DFT" example, which you can find on the Ettus Research GitHub repository.

One thing to consider is that the various GitHub repositories I've pointed at, will give you access to the moving parts of how all this works.

I will mention that my favourite tool in this space continues to be GNU Radio, but I understand that you might not want to roll your own tool from parts. That said, rolling your own is in my experience a great way to discover precisely what you don't know and to come away learning more, but then, that's just me.

Regardless of your chosen tool, I think the takeaway should be that when you try something new, even if it's only new to you, the idea of writing down what you discovered and sharing it, is a fantastic way to grow our community. Remember, just because something is old hat to you, doesn't mean that it is to the person you share it with.

Besides, based on the current global birth rate, there's at least a thousand babies born during the past four minutes, some of whom will become radio amateurs, so, share.

Said differently, if you come across a person who has never heard of the "Diet Coke and Mentos" thing, it's your job to immediately drag them to the nearest grocery store and introduce them. In case you're wondering, xkcd 1053.

Now, I'm going to update the firmware on my PlutoSDR and have a play, I already know about the Mentos, but if you don't, you're in for a treat.

What are you going to do next?

I'm Onno VK6FLAB

Recently I discussed the idea of listening to the radio spectrum across the internet for the purposes of getting signal into your shack when radios, or in my case, antennas are causing you challenges.

I continued to explore and discovered a project by Jacobo EA1ITI, called "radioreceiver". Behind that unassuming name lies a tool born in 2014, that allows you to plug an RTL-SDR dongle into your computer, open up your web-browser, and listen to the radio signals that your dongle can receive.

In case you're unfamiliar, an RTL-SDR dongle is a small USB device, looks a lot like a USB thumb drive, jump drive, data stick or flash drive, basically a hunk of plastic with a USB connector on it. An RTL-SDR dongle generally also has some form of antenna connector. It's typically sold as a digital radio and digital television receiver, but websites like rtl-sdr.com sell purpose built ones. They can be found starting at about $15.

I realise that this is using a local receiver, with a local antenna, but it's inside a web browser, which is half of what I expected. When you hit the play button in the bottom of the screen, you'll be prompted by your web browser to give permission to access your RTL-SDR dongle and the fun starts. You'll see a live waterfall, hear audio, and have the ability to tune to any frequency you can reach. Depending on your dongle, typically somewhere between 500 kHz and 1.76 GHz.

The application consists of seven files, a total of 352 kilobytes that you can store on any web server and run, with one caveat, in order for your web browser to talk to your dongle, it needs to be served using HTTPS. Jacobo has set-up radio.ea1iti.es and I've set-up sdr.vk6flab.com, both showing the same tool. You'll find the code on my VK6FLAB GitHub repository, and of course on Jacobo's.

There are some things you need to know. You will need to use a web browser that supports WebUSB, currently that's Chrome, Edge, Opera and several others, sorry, Safari and Firefox don't .. perhaps it's time to talk to Apple and Mozilla. All is explained if you click on the little question mark at the bottom of the screen, it will even tell you if the browser you're using to read the help is compatible or not.

If you have an Android phone, you can run this tool too, although you will need to find a way to connect your dongle to your phone. I'm currently limited in my ability to test this and you may need to install some drivers on Windows and Linux, but MacOS and presumably Android, works out of the box. The software also supports offline operation, so you can load it as a Progressive Web App, or PWA, and use it in the field away from the internet.

Did I mention that all the decoding is happening inside the web browser, so you can see which code is doing what .. and before you ask, yes, it's minimised in the browser, which you can make into human readable code, but when you look at the source, it shows precisely what is happening, all written in Node.js, TypeScript and JavaScript.

It supports CW, SSB, AM, Narrow and Wideband FM and decodes stereo, something which none of my amateur radios do.

You might be able to tell that I'm excited. It's because this is providing the basic functionality of a radio inside a web browser, and I didn't need to install it to get started. On the Macintosh I tested this on, I literally opened the web page, plugged in a dongle and hit play. Just so we're clear, just because this is using a web page on a web server, you accessing it will only give you access to your radio not mine.

This of course opens the doors to all manner of other fun stuff which I'm expecting to play with for the next little while, and yes, this is also Bald Yak adjacent, I'm aware.

In the meantime, you can play with this right now, sdr.vk6flab.com is the place to go. Word of warning, it's addictive and easy to forget it's a radio with an antenna plugged into your computer, so take precautions when electrical storms are about.

Look forward to hearing what you discover.

I'm Onno VK6FLAB

Every single radio amateur has come to this hobby with an itch to scratch. Time and again I've seen amateurs around me pursue that particular purpose, only to come out the other end with a look of bewilderment writ large across their face. For some amateurs it means the end of their involvement in the hobby, for others it starts a new journey into the unknown.

One of the ways we explore our community is by travelling out of our shack into the big outdoors in whatever form that takes. Popular activities include setting up a radio in a location and talking to others, known colloquially as an "activation". We do this all over the planet. Perhaps the most recognisable of these is IOTA, or Islands On The Air, where a station is erected on an island and contacts are made. As amateurs we cannot help ourselves and seem to have an insatiable need to measure our prowess. We do this by counting how many contacts, callsigns, countries, grid-squares, or in this case, islands, we've managed to put in the log.

If an island represents a new callsign, a new country, and a new grid-square, the contact making will turn into a feeding frenzy that can last for days, especially if the station offers multiple bands and modes, making the effort all the more tempting.

We don't stop with islands. Summits, with Summits On The Air or SOTA are popular, as are Parks, POTA, and even over a weekend, the International Lighthouse and Lightship Weekend, or ILLW.

Some of these activations follow rules set out by amateurs like you and I, who thought it would be fun to track such activations and encourage others to participate. For example IOTA World publishes a four page document outlining what's required for those on the island, activators, and those trying to make contact, or chasers. This raises an important point. Rules require documentation, which leads to discussion and disagreement, and versions. I can show you two versions of the IOTA World rules, neither is dated, of course both are different, so if you're going to publish rules, make sure you add a date or version, preferably both, to the rules document.

Disagreements aside, sometimes there are multiple programs with the same name or aims. Two groups came up with the same idea and didn't know about each other, or, a group in a different country wanted to run the show in a different way and a new group was formed.

I'm mentioning this because sometimes these groups are antagonistic towards each other and have forgotten that the whole point of this is to have fun.

So, what else can we activate?

Well, there's Castles and Stately Homes, Bunkers, Beaches, Museums, Walmart Parking Lots and even Toilets On The Air, mind you, Slow Scan Television, or SSTV is discouraged as a mode.

The other day the power was off for maintenance in my street and I planned on escaping to the local library, which caused me to search for libraries across Perth. It seems there's pretty much one in every suburb and I considered the notion of activating a library or three, comes with easy access to public transport, a car park, and even toilet facilities, what's not to like? I wondered what might be a suitable exchange so it could incorporate the library itself, promoting amateur radio and libraries, two birds and all.

I made a comment on mastodon.radio and it turns out that Frank K4FMH beat me to it, several years ago. Libraries On The Air, or LiOTA. I've been hunting for a dataset of libraries in Australia to give to Frank, but it's been slim pickings, despite there being over 10,000 of them, apparently around 10% of those public.

It raises another question, is there a directory of activation types anywhere? I couldn't find one, so I started a list on my GitHub repository. Feel free to add any I missed.

Toilet jokes aside, consider that TOTA is being held during the annual Hackers On Planet Earth conference and it will introduce new people to our amateur community, which ultimately might be the best reason to have fun, get on-air and make noise.

I'm Onno VK6FLAB