brainwagon

Another link to some interesting experiments on building your own thin-film transistors. And a Quarter Gets You Coffee » Homemade Thin-Film Transistor Experiments Addendum: Of course any mention of building your own transistors would be remiss if it didn’t mention hacker-savant Jeri Ellsworth. She did an amazing job fabricating her own semiconductor devices, and in […]

While listening to the “This Week In Amateur Radio” podcast this morning, I heard reference to a new record setting non-line-of-sight one way contact that took place over optical wavelengths. A sucessful transmission over a distance of 288 kilometers was achieved by using an LED based transmitter. The report (PDF) provides many interesting details, such […]

Back in 2008, I blogged about a stupid program I wrote to implement a Morse Beacon on the Arduino. I couldn’t find that code, and it was stupid anyway, so I went ahead and implemented a new version, with an added improvement: it doesn’t hardcode dots and dashes, it has a built in table. Right […]

Just flipping around the web tonight, found another interesting MEPT (Manned Experimental Propagation Transmitter) project that uses solar power an a small Atmel AVR processor. Very neat. 30m QRSS Transmitter (clayton.isnotcrazy.com)

I was trying to remember where I had seen this excellent online book, and finally found the link that lead me to it. Archived here for posterity. Frank tries to never buy radios, but literally build his entire station. This isn’t to save money, it’s to foster an understanding of how things work in a […]

I’m interested in short vertical antennas, so I keep collecting links to interesting article. K6MM has a nice description of his work with a 25 foot tall HWV antenna for 160M, built from three segments of PVC pipe, a capacitance “top hat” and 8 ground radials. K6MM Home Page Addendum: Another page describing a very […]

I mentioned G3ZJO’s “WSPR Organ” idea a couple of days ago: he has a much better write up of its success on his own blog. Check it out: WSPR Organ – Computerless WSPR TX – Radio – HF to Microwaves I think the idea of calling this “computerless” is a teensy bit misleading: he does […]

This is just a brief note to myself to archive, well, what amounts to a single command that processes an audio file, but to stand as a placeholder for an interesting topic that I know virtually nothing about. 🙂 Here’s the basic idea: Amateur radio SSB communications are limited to narrow bandwidths (around 2.7khz is […]

The Knightsqrss mailing list still intrigues me, although my own qrss beacon has been off the air for a while (I’m trying to get around to homebrewing its replacement, but have been distracted by other facets of life for a while). Recently, Eddie G3ZJO offered this rather interesting circuit which I scratched my head about […]

I missed out on last night’s Echolink QRP confab (Sundays, at 6:00PM Pacific time) but I did notice that Henry had posted a summary of topics and links (thanks again Henry) and included a link to Chuck Adam’s lab notebook. I’m just about to dash off to work, but it looks like it has lots […]

While digging around for some information on crystal radios on the Internet (since i seemed to have misplaced the book on the subject I was looking for) I encountered some references to a book which happened to have been digitized and made available on archive.org. This book was published by the National Bureau of Standards, […]

Ben Tongue’s article on using a supercapacitor to hold energy harvested from an antenna tuned to strong local broadcast system got me thinking about supercapacitors again. Digging around uncovered a link to a DIY project (very simple) for creating your own electric screwdriver powered by supercaps. (I think they are a bit cavalier with the […]

I subscribe to the very interesting QRP-L mailing list, and recently read an article by Michael Rainey, AA1TJ about an interesting radio and set of QSOs that he conducted. Michael’s experiments are amazing and cool, but I think his latest effort takes the cake: he had a number of QSOs using a transmitter powered entirely […]

I don’t know why this percolated to the top of my consciousness today, but I thought I’d dump a link here so I can find it again. I recalled reading an article about the use of a particular special MOSFET device for use in crystal radios. It took me a tiny bit of time to […]

I was reviewing Stu’s articles on his “Ethergeist” blog again regarding his QRPp WSPR beacon, and was admiring his nice looking prototypes. I’ve goofed around with using tin snips to cut small pieces of copper clad and gluing them down to make solder pads, but Stu just uses a carbide tip scribing tool to cut […]