A motley collection of ideas
Homemade circuits, experiments, tinker-friendly electronic ideas, and and things related to amateur radio.
Every day, hundreds of tiny, barely visible instruments rise above our heads. These are weather radiosondes: they collect data from the lower and upper atmosphere and, a few hours later, quietly come down somewhere over fields, forests, and villages. The signals from these sondes can be received by anyone — and that’s where the exciting … Read more
I wanted a simple, inexpensive antenna for my Little Airshow Radio. The 108–137 MHz range is the VHF airband, where the wavelength is roughly 2.18 m to 2.73 m. That means any resonant antenna designed for this range tends to be physically large. If you’re looking for a small, portable solution, you’ll need to make a few compromises. … Read more
Radiosondes fall back to Earth every day. Most people never notice them. With a small, purpose-built receiver like the MySondy Go, you can not only notice them, but actively track, decode, and recover them. This article documents our build of a MySondy Go device, including a custom-designed 3D‑printed enclosure optimised for real-world field use. Why … Read more
I have a plasma globe that I received about 15 years ago to create illustrations for an article. One day I showed interesting experiments with it, but now I would like to write about why the globe broke down. As is well known, the plasma globe (or Tesla globe) is a decorative glass sphere filled … Read more
The DP–2 digital intercom indoor units are widely used. They are compatible with the Codefon intercom systems commonly found in Hungary, and their circuitry is completely identical to the Codefon EVK apartment handset. On some versions, an external doorbell button can also be connected, and there is an option for an external loudspeaker output, which … Read more
Hunting meteorological radiosondes is one of the exciting pastimes of amateur radio enthusiasts.These small instruments—launched into the stratosphere by meteorologists using hydrogen balloons—must be tracked by receiving their signals and following their trajectory based on their GPS data until they land somewhere. And those who are skillful may even take the “prey” home and give … Read more
A lady with no technical background inherited a pile of assorted multimeters, and—rather unwisely—dared to ask in a Facebook group devoted to such things how much each might be worth. She did not receive many straight answers. Some people immediately latched onto one instrument or another and offered her a token amount; others promptly denounced … Read more
We found this instrument at a collectors’ fair with my partner. We simply couldn’t resist it, so we took it home for 12 euros. According to its technical logbook, it left the Gamma factory on August 13, 1983, and was last calibrated on July 25, 2000. After cleaning and restoring it, it became a very … Read more
Some time ago, if I remember correctly, I got this instrument for 1,000 forints, and more recently I parted with it due to lack of spac. The first impression, despite being a tube instrument, is that it is incredibly light. No doubt, it’s a rather large unit—and you could practically keep a guinea pig in … Read more
The oscilloscope type 1536 is used in servicing, by amateurs, and in education. Its small dimensions and low weight allow it to be carried in hand luggage. The cathode-ray tube has a useful screen area of 4.8 × 6 cm. The instrument has one vertical channel and a time-base generator. The separate X-input also makes … Read more