On Fri, Feb 26, 2010 at 9:36 AM, Bruce Bostwick <[email protected]>wrote:
> On Feb 25, 2010, at 9:47 PM, John Williams wrote: > > On Thu, Feb 25, 2010 at 7:37 PM, Nick Arnett <[email protected]> >> wrote: >> >>> However, some of >>> the spectrum is still restricted to CW (code) only. >>> >> >> Right, the masochist channels :-) Or, perhaps, the apocalypse >> practice channels. >> > > There's actually an interesting tangent here, by the way, on the subject of > single sideband (SSB) reception and transmission. SSB effectively > translates a slice of spectrum either up from or down to audio baseband more > or less intact (inverted in the case of LSB), and it's amazing what your > ears can learn to figure out just from what you hear in that slice of > spectrum, especially with tuning up and down the dial. > > And the possibilities only multiply when you feed that audio from the radio > into, say, the sound card of a computer, and vice versa. DigiPan is only > one of a nearly infinite number of possible examples of that. All the DSP > capability of your computer interfaced quite elegantly with that old > Hallicrafters tube rig from the attic and maybe an audio interface with an > audio-triggered transmit relay. I don't know about you, but I find that > thought rather exciting. :D > Wowza... just read a little about DigiPan. Amazing. Personal computers sure have transformed amateur radio from when I first got interested. I think the first time I ever encountered it at all was in 1968, when my older sister was an exchange student in Columbia and we talked to her via HF at the University of Pittsburgh's radio club. I remember it sort of freaking out my younger sister, the one who died last month. She was only six or seven years old and found the whole thing scary. They patched the audio into a telephone handset and that helped her deal with it. (And an interesting experiment: Feed the I and Q outputs of a quadrature > detector to a pair of stereo headphones. Apparently the brain's auditory > cortex is wired in a way that takes unique advantage of that format. And > you're literally *listening to signals on the complex plane*. What's not > cool about that? It must be very cool, since don't quite understand what you're saying. ;-) Nick
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