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| Any Shortwave Radio Tips for a Noob Considering the Hobby? |
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| xrunner:
Your other questions have been answered, but here's some trivia about the sideband practices on the HF bands. The tradition of using LSB below 10 MHz, and USB above 10 MHz, goes back to the very early days of SSB. Early rigs had very simple designs and an IF of 10.7 MHz. These radios passed the lower sideband below the IF frequency, and the upper sideband above the IF frequency. There was no option to choose a particular sideband as there is now. That old limitation has become the standard. But of course it's not illegal to use any sideband you wish on any band. |
| bd139:
Yes we've got some locals on 80m here who like to use USB for some reason. I haven't worked out why. |
| Sal Ammoniac:
--- Quote from: xrunner on December 12, 2019, 03:02:54 pm ---Your other questions have been answered, but here's some trivia about the sideband practices on the HF bands. The tradition of using LSB below 10 MHz, and USB above 10 MHz, goes back to the very early days of SSB. Early rigs had very simple designs and an IF of 10.7 MHz. These radios passed the lower sideband below the IF frequency, and the upper sideband above the IF frequency. There was no option to choose a particular sideband as there is now. That old limitation has become the standard. But of course it's not illegal to use any sideband you wish on any band. --- End quote --- Caveat: those sideband practices on the "HF" bands that you describe only apply to the ham bands. Other users of SSB on HF, with very rare exceptions, always use USB regardless of the frequency. |
| fourfathom:
Most (all?) of the FSK-style digital modes use USB on the HF ham bands. However, this is USB in name only, as the actual transmitted signal is a single frequency, or multiple single-frequency signals that are individually modulated in frequency and/or amplitude and/or phase. The only thing "USB" about them is that they are usually generated by sending an audio "baseband" signal into a SSB transceiver (set for upper sideband), and received in the same way. These signals can also (and sometimes are) generated directly at the output frequency by simple frequency-shifting oscillators -- no sidebands. Actually, even these signals have sidebands. In the case of the WSPR mode, the modulation rate (Baud rate) is 1.4648 Hz (yes, that's quite slow), and there will be upper and lower sidebands spreading out from these signals spaced at 2x the baud rate. These fall off quite quickly, so the occupied bandwidth is very small. The same holds true for analog frequency-shift modulation such as marine WFAX (weather facsimile charts) on the HF bands. Your receiver will be in USB mode, and the shifting frequency signal will be converted to an analog baseband audio tone, varying a couple of KHz. The signal isn't *really* USB, but that's how we receive it to get the demodulated audio right-side-up. If we were to receive in LSB mode, then black would decode as white (and the synchronization signals wouldn't work). |
| james_s:
I have a Grundig that I've been fairly happy with but if you want something cheaper I'd say read the reviews on Amazon, you can get something decent for not much money these days. Shortwave is definitely not what it used to be, mostly just dead air these days. I do enjoy picking up and identifying LW NDBs used for air traffic, and as of a few years ago I was still able to find a "numbers" station which I believe was broadcasting out of Cuba, there used to be loads of those used for transmitting covert messages to spies, it was a lot of fun to hunt for them. Occasionally I hear local hams yakking about their medical problems and every now and then there's still some foreign broadcast. Oh and of course WWV/WWVH is still around for now anyway. |
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