I enjoyed compiling last month’s Rad[io] links (silly name aside!) and I’ve been trying to keep up the pace with posts. I’ve stopped using google analytics, so I don’t have much idea how popular the last post was, but whatever 🤷! Here are a few more interesting items I’ve found over the last few weeks.
So. You Bought A VNA. Now What?
By now, most people have heard of the nanoVNA, the tiny touch screen vector network analyser you can get for very little money. If you don’t have one, order one now then come back. I’ll wait 😁
This hackaday post has some great info on the basics of how they work but doesn’t mention software! In my opinion NanoVNASaver transforms the VNA from a tiny toy with terrible controls into something far more usable. All you need to do it plug it into a computer, and can you benefit from a big screen and proper graphs.
If you’re after something more scalar, then look at the Antuino, by the maker of the BITX. This uses an Si5351 oscillator and a superhet receiver to measure antenna or circuit responses at exact frequencies, so it’s pretty cool, but you don’t get the complex impedance information you’ll get from the nanoVNA.
Bottle transmitter (De flessenzender)
In 1953, a storm and very high spring tide caused massive flooding, primarily in the Netherlands, but also in parts of England and Belgium. Radio amateurs came to the Belgium’s rescue and helped organise an emergency radio network. Perhaps unsurprisingly, this is commemorated each year on the anniversary.
While I was reading the GSRP club mailing list the other day, PA3BCB (and others) mentioned the fascinating story of Peter Hossfeld, a technician at a radio shop, who actually wasn’t a ham. He built an 80m emergency tube-based transmitter in a single night, using a wine bottle as a former for a coil, and a light bulb to help tune the output. He then used this to relay messages the next day! There’s more info on this fascinating story at PA3ESY’s site, and the Dutch SRS held a competition to build replicas in 2019. I’m sure there’s way more about on this, but my tolerance for google translated text is fairly low!
Window mounted Log spiral antenna
This ultra-wideband omni-directional antenna comes complete with suckers to stick it on a window and has a frequency range of “300MHz to ~3GHz and beyond”. There’s a lot of design information on the HexAndFlex blog, as well as some stuff on the nanoVNA, so it’s worth a look. I imagine antennas like these would work really well with SDRs.