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On Jun 18, 8:30 am, Bob wrote:
Hello, I am new to SW and have recently purchased a ka1103 radio. It seems to work very well, but I have trouble with SSB. I live in NY and I don't seem to be able to pick up SSB. I am trying some of the The SSB USB (AFRTS) frequencies listed in the SW schedule from a magazine. I tune to the frequency, switch to SSB and then try to fine tune into a broadcast. I just can't seem to pick anything up. Could it be the radio or isn't there a strong enough signal? How can I determoine the reason? Thanks It's always good to get a feel for the SSB feature of your radio by "driving it around" a bit on an easy signal before you try to use it on a very weak signal like AFRTS can be sometimes. For practice, you can always tune a local AM broadcast with your SSB feature turned on. If you have a USB/LSB switch or mode button, try both. If you have a dial that's marked "BFO" or "clarifier" or similar, twiddle that. If you can get an intelligible signal in that mode, you know your receiver works OK in SSB mode and will get a feel for how to work the controls. You will probably hear a horrible screaming whine which changes pitch as you tune which won't happen with a "true" SSB only signal, so turning the volume down low isn't a bad idea. When it's tuned so the pitch of the whine is so low you can't hear it anymore, you're just about perfectly tuned. Tune for maximum natural sound. In SSB mode, when you run by an SSB signal, instead of an annoying high pitched whine that drops as you get closer and closer to the signal (and rises again if you continue past it), instead you'll hear a gibberishy sound that changes pitch as you change frequencies or rotate the clarifier/BFO knob. Start slow, and see if you can get clear and natural sound. If the voices or music still don't make sense [insert commercial radio-bashing joke here] , try the alternate sideband if your radio has a USB/LSB mode switch. (If it has a BFO knob, it should make sense when you have the knob set right without any other adjustments.) Using a regular AM radio station works because a standard AM broadcast band signal is both a USB transmission, an LSB transmission, and a carrier transmission, all in one. The USB and LSB parts carry identical information (in mirror image), and the carrier is there to keep the receivers simple. You can throw out the carrier and one of the sidebands and lose basically nothing. That's how SSB works. (The carrier is what makes the whine.) One DXing trick is to leave your radio in SSB mode as you tune even for AM signals. Even VERY weak signals that are barely discernable, will cause an audible squeal as you tune past them, so it's a good way to ensure you don't miss a weak signal. Another neat trick for radios with a selectable USB or LSB mode, is to tune an AM signal very carefully, and then listen to only the USB or LSB side, whichever has less interference. Sometimes this can really save your ears. A last trick in "fun with SSB" is if you can't tell exactly what frequency a station is on. In AM mode, you can be tuned off a bit and not really hear any difference. But if you turn on SSB you have to be pretty close to exactly on the carrier frequency for the whine to disappear. This ONLY works on radios that don't have a knob for BFO or clarifier, though. Hope this helps a little. -- ross |