A motley collection of ideas
In this section, you’ll find all kinds of articles. Some of them are machine translations of my older writings in Hungarian, which may contain grammatical errors or content that is no longer up to date. I apologize for these mistakes, and I would be very glad if you let me know when you come across any. Happy reading!
Fluorescent lamps are becoming less and less fashionable these days, as LEDs are pushing them out—but they’re really not that bad. The technology improved a lot between the 1970s and 1990s: the unpleasant light of old fluorescent tubes is a thing of the past. Flickering and color distortion have been reduced so effectively that in … Read more
With Schlieren photography, even a person’s breath can be captured. It is often used to illustrate various flows, shockwaves, bullets, flames, and fire propagation. NASA has even developed a version of the method that allows supersonic aircraft to be photographed in flight. Most people have probably seen such images before — in recent years, the … Read more
In the spring of 2019, I wrote an article about the so-called “wasp garage,” prompted by the fact that these things started appearing in many supermarkets and pet stores. Lots of people bought them, put them out in their gardens—and nothing happened. NGOs and local governments also installed them in public spaces, and there are … Read more
I inherited this device from my father—he brought it from the Soviet Union at some point. It was manufactured in 1974 and is a typical example of the simple yet extremely robust Soviet devices. It doesn’t contain any “smart” electronic circuits, so there’s nothing in it that could burn out or break. It’s simply built … Read more
It is well known that, thanks to its favorable balneological and geothermal conditions, Hungary is a country rich in thermal waters. Although the demand for the energy utilization of thermal water is increasing, geothermal energy remains our largest untapped energy source, due to the unique geological characteristics of the Carpathian Basin. The average domestic heat … Read more
Spotters, SWL (shortwave listening) enthusiasts, and amateur radio operators all enjoy listening to aircraft communications — and nowadays, even drone pilots find it useful to monitor air traffic. A good handheld airband transceiver easily costs well over a hundred thousand forints, whereas the device described here is dirt cheap by comparison. Of course, it’s not … Read more
The handheld meter has been a staple in almost every technician’s toolkit for nearly 100 years. Today, the majority of handheld meters have digital displays. However, until the 1970s, most meters featured analog readouts. These were typically multimeters capable of measuring voltage, current, resistance, and occasionally capacitance and frequency. “Pocket watch”-style measuring instruments were popular … Read more
The purpose of this project is to extend the range of an older (and more affordable) frequency counter into the VHF and UHF bands. The idea was inspired by an article published in Rádiótechnika (1990/7, pp. 341–342), although the original circuit was designed by Zeljko Bozic, S52ZB, and later published in a 2006 issue of … Read more
Sometimes I find myself wondering which of my portable digital voltmeters I can actually trust. The old 4½-digit M4650? The Fulke? Or the younger METEX? (Okay, I have one from Lidl too, but that’s not even a question.) Generally, they all show pretty similar values, and I rarely need better than 1–2% accuracy—but it still … Read more
I needed a compact power supply capable of providing roughly 5–20 V DC and 12–16 V AC. Because an AC output was required, I chose a conventional transformer—similar to those used in alarm control units and intercom systems. This project was inspired by the Chordless Lab Power Supply on Thingiverse. DC Section The DC side is quite simple: a … Read more