Foundations of Amateur Radio

On the 12th of December 1961, before I was born, before my parents met, the first amateur radio satellite was launched by Project OSCAR. It was a 10 kilo box, launched as the first private non-government spacecraft. OSCAR 1 was the first piggyback satellite, launched as a secondary payload taking the space of a ballast weight and managed to be heard by over 570 amateurs across 28 countries during the 22 days it was in orbit. It was launched just over four years after Sputnik 1 and was built entirely by amateurs for radio amateurs.

In the sixty years since we've come a long way. Today high school students are building and launching CubeSats and several groups have built satellites for less than a $1,000. OSCAR 76, the so-called "$50SAT" cost $250 in parts. It operated in orbit for 20 months. Fees for launching a 10cm cubed satellite are around $60,000 and reducing by the year.

If that sounds like a lot of money for the amateur community, consider that the budget for operating VK0EK, the DXpedition to Heard Island in 2016 was $550,000. Operation lasted 21 days.

I'm mentioning all this in the context of homebrew. Not the alcoholic version of homebrew, the radio amateur version, where you build stuff for your personal enjoyment and education.

For some amateurs that itch is scratched by designing and building a valve based power amplifier, for others it means building a wooden Morse key. For the members of OSCAR it's satellites. For me the itch has always been software.

Sitting in my bedroom in the early 1980's, eyeballs glued to the black and white TV that was connected to my very own Commodore VIC-20 was how I got properly bitten by that bug, after having been introduced to the Apple II at my high school.

I'm a curios person. Have always been. In my work I generally go after the new and novel and then discover six months down the track that my clients benefit from my weird sideways excursion into something or other.

Right now my latest diversion is the FPGA, a Field Programmable Gate Array. Started watching a new series by Digi-Key about how to use them and the experience is exhilarating.

One way to simply describe an FPGA is to think of it as a way to create a virtual circuit board that can be reprogrammed in the field. You don't have to go out and design a chip for a specific purpose and deal with errors, upgrades and supply chain issues, instead you use a virtual circuit and reprogram as needed. If you're not sure how powerful this is, you can program an FPGA to behave like a Motorola 65C02 microprocessor, or as a RISC CPU, or well over 200 other open source processor designs, including the 64-bit UltraSPARC T1 microprocessor.

I'm mentioning this because while I have a vintage HP606A valve based signal generator that I'm working on restoring to fully working. Homebrew for me involves all that the world has to offer. I don't get excited about solder and my hands and eyes are really not steady enough to manage small circuit designs, but tapping keys on a keyboard, that's something I've been doing for a long time.

Another thing I like about this whole upgraded view of homebrew is that we as radio amateurs are already familiar with building blocks. We likely don't design a power supply from scratch, or an amplifier, or the VFO circuit. Why improve something that has stood the test of time? In my virtual world, I too can use those building blocks. In FPGA land I can select any number of implementations of a Fourier Transform and test them all to see which one suits my purpose best.

In case you're wondering. My Pluto SDR is looking great as a 2m and 70cm beacon, transmitting on both bands simultaneously. It too has an FPGA on board and I'm not afraid to get my keyboard dirty trying to tease out how to best make use of that.

What homebrew adventures have you been up to?

I'm Onno VK6FLAB