These little radios don't have ISB, but it is still being used in a lot of LF/HF applications.I don't quite understand what we're trying to prove here. If you are listening to an SSB station and have switched to the correct sideband, say USB, then there should be no transmission on the LSB sideband. If they are using ISB, independent sideband, where there are two different audio signals in the sidebands you need very good isolation in the receiver - often an ISB station has a reduced carrier which the receiver uses to regenerate the missing carrier so that it is exactly in phase with the received sidebands. It was used extensively by telecoms companies for HF communication worldwide before satellites made it so easy, now ISB is rarely heard.
I don't quite understand what we're trying to prove here. If you are listening to an SSB station and have switched to the correct sideband, say USB, then there should be no transmission on the LSB sideband.
Listen on 3819 in the evenings around 6pm cdt give or take some minutes. One group is on lower the other group is in upper side band. One group isn't talking to the other group. It's possible. I am guessing both groups like to be on 3819 and maybe they decided that's the only way to keep 3819.Hmmm...something is off here. The standard on 75/80 has always been LSB, not USB. Not to say that it can't happen, but that's the standard
Mike
Propagation in OK won't be the same as it would be here in the DC area (totally different paths); however I have a sneaky suspicion that the net that is being heard on USB is really a couple of hundred hertz off 3819. Using a wide filter, it's quite possible the radio would mis-read that as an USB signal. Try using a narrower filter on that same signal (if one is available) and see if the USB signal is still present. If it's greatly reduced or gone, this is what is happening
This is not the fault of the radio; most consumer grade radios would be guilty of this too. A ham transceiver with good filters probably wouldn't hear the higher transmissions unless the radio is retuned.
Mike
You can have two nets on one frequency one net on lsb the other on usb they won't interfere.2.5 or 3 khz filters aren't narrow enough, since SSB are around 3 khz. You need some more narrow like 1.8 khz to be able to filter out one of the transmissions.
the eton Elite Executive has 10hz resolution on the fine tuningI tried a Kiwi SDR in Texas, and I'll be damned - 2 separate transmissions - one on LSB, the other on USB. I would have thought the ever present holier-than-thou band guardians would squawk, but there they are
Interesting find. Most consumer portables can't discriminate that well - particularly with only a 1 khz resolution...Mike
The wide filter might capture part of a signal that far off, but it would sound like chipmunks if the radio is tuned to 3819.I have a sneaky suspicion that the net that is being heard on USB is really a couple of hundred hertz off 3819. Using a wide filter, it's quite possible the radio would mis-read that as an USB signal.
That would have to be a poor quality filter. Good filtering only filters upper or lower side band. If it is widened it is set to go into the direction of the sideband mode used. The eton Elite Executive does exhibit proper USB/LSB filtering. It's amazing how they got it to work in a small package.The wide filter might capture part of a signal that far off, but it would sound like chipmunks if the radio is tuned to 3819.
Depends on the bandwidth of the filter. The bit to which I was replying suggested the signal wasn't 3819.000 USB but something like 3819.200 USB. If using a 2kHz filter, that signal on 3819.200 would be well within the range of the filter. Indeed, you'd need a 200Hz filter to eliminate that signal entirely, which would be useless if listening to someone talk.That would have to be a poor quality filter. Good filtering only filters upper or lower side band. If it is widened it is set to go into the direction of the sideband mode used. The eton Elite Executive does exhibit proper USB/LSB filtering. It's amazing how they got it to work in a small package.
but he found out i was right when he checked 3819 with a KiwiSDR. See post 13Depends on the bandwidth of the filter. The bit to which I was replying suggested the signal wasn't 3819.000 USB but something like 3819.200 USB. If using a 2kHz filter, that signal on 3819.200 would be well within the range of the filter. Indeed, you'd need a 200Hz filter to eliminate that signal entirely, which would be useless if listening to someone talk.
My point was that if tuned to 3819.000, a USB signal on 3819.200 would be readily identifiable as being off frequency. Sensitivity to off-frequency tuning varies from person to person, but you'd need to be deaf to not notice a 200Hz shift.