Radio was booming in the 1920s: transmitters had started using the pure tone of 'continuous wave' signals, replacing signals sent with sparks, and increasingly selective and sensitive receiver circuits offered greater range seemingly by the month. Amateurs, not yet able to tame their simple transmitters with crystal-controlled oscillators, constructed them on simple wooden boards with heavy wiring and large inductor coils in order to keep heating from causing their signals to drift. These homebrew transmitters were ongoing experiments in electronics and engineering. The position of a coil might increase output power but cause the signal to sound like a buzzsaw. If you could find a higher voltage power supply, that too would raise its power, but the increased currents in the rig would add more drift: if the other guy can't find your signal wandering up and down the band, what use is that extra 3 watts? The 1929 QSO Party Every year the Antique Wireless Association holds a tw
The AA2TX parasitic lindenblad, which was published in Feb 2010 QST (and has been available online for some time), is proving to be an enjoyable project. I have modified some components because I could not find them here in Atlantic Canada. The #8 aluminum wire for the passive elements is not in our big box stores (different wiring regulations?), and the PVC ferrules require a special order, at least at this point in the year, when no sane person would be installing eavestroughing. So I made do with what I had, and the results are encouraging.
Lots of progress with 'satpack', my Arduino-based full-doppler-tuning satellite tracking application. On the right, you see a cardboard mockup of the pcb. On the software side, I've checked a fully working version of the code into the SVN repository.
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