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Let the newsgroup scroll proclaim that "Frank Dresser"
scribed upon its pages in news:gTsFb.225436 : These comments are addressed to Frank, Starman, and David. I've owned this radio since 1971, and have never really understood how all these frequency notation devices (band width, logging scale, tuning, etc.) related to one another. Finding out that some of this relates only to ham radio has been a TREMENDOUS help. Years of curiosity have been answered with one message. All three answer are seriously helpful. I've printed these out for reference. Say the bandspread was set to zero at at a known transmiission at 9760kc. Another known signal at 9580 kc might turn up when the bandspread indicator gets to 18. That's a 180 kc difference for every 18 bandspread divisions. Or something like 10 kc for every division. The breakdown probably isn't linear, so smaller differences in frequency will give better results. A crystal calibrator could be used to give regular dependable signals across the bands. 100 kc was a common crystal calibrator frequency. That makes the math easier. The more expensive radios of that era had internal crystal calibrators. A SWL could keep all this info in a notebook and do the hard work only once. Good info! The analog radio's local oscillator can be heard with with a digital radio. The local oscillator will usually be 455 kc above the received signal. Sometimes the LO is 455 kc below the signal, usually on the top band. Using a digital radio in this way might sound silly, but even a very cheap digital can give a very precise readout to a better quality analog readout radio. There's now a digital readout which can be added to an old radio: http://www.aade.com/#dfd Do you have the Hallicrafters manual for your radio? There's probably one at the BoatAnchor Manual Archive. Yes, I found that and downloaded it some time ago, but the manual assumed the reader already had some working knowledge, and basically outlines details specific to the S-108 operation, I think. -- Allen McBroom www.NPSTKD.com Remove WOOF when replying by email |
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