3 ms·

Thanks! I'd long wondered exactly how radio carriers were modulated before vacuum tubes. (Technical details of that era are often skimpy in histories.) This ch

Thanks! I'd long wondered exactly how radio carriers were modulated before vacuum tubes. (Technical details of that era are often skimpy in histories.) This chronology of AM radio is interesting: [https://web.archive.org/web/20071118155548/http://members.aol.com/jeff560/chrono1.html https://web.archive.org/web/20071118155548/http://members.ao...] It mentions Fessenden's 1906 Xmas broadcast, and it looks like he'd just gotten one of Alexanderson's alternators. Paul Mali, Magnetic Amplifiers (1960;PDF) [https://web.archive.org/web/20061114175548/http://www.pmillett.com/Books/mag_amp.pdf https://web.archive.org/web/20061114175548/http://www.pmille...] Home-made MA's: [http://sparkbangbuzz.com/mag-amp/mag-amp.htm http://sparkbangbuzz.com/mag-amp/mag-amp.htm]

myself248 5y ago
You can hear an Alexanderson live on the air, twice a year! https://alexander.n.se/en/the-radio-station-saq-grimeton/saq-transmissions/ https://alexander.n.se/en/the-radio-station-saq-grimeton/saq... Might want to get a head start on the receiving hardware, though. Most SDRs don't go that low, and though soundcards can go that high, their input impedance may not be well suited to whatever antenna you can cobble up. Oh, and you'll want an absolutely enormous antenna. Get a roll of cheap fence wire and string it halfway down the block...
- Johnythree 5y ago
  Many enthusiasts are using a tiny voltage probe antenna for VLF. https://www.on8im.be/en/active-antenna-pa0rdt.html https://www.on8im.be/en/active-antenna-pa0rdt.html