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For a long long long while now, I have had varying reports of<br>some sort of problem where the rxsquelch setting for chan_usbradio<br>changes depending on whether you just did a 'radio tune rxnoise'<br>and then saved it, or you just brouight up chan_usbradio from<br>its saved configuration. In addition, I myself, have seen cases<br>where the RSSI and squelch values seemed just really silly<br>high for some reason.<br><br>I believe I have found the culprit and have fixed it. It turns out<br>that the hardware gain of the USB sound chip was different<br>depending on whether it just had a 'tune rxnoise' or if it<br>was set up from the config file. It turns out that because<br>of a rounding error, it would often set its value 1 too low<br>(compared with what the 'tune rxnoise' calculated it<br>should have been). Believe me, when you only get a range<br>of 1 to 16, 1 too low makes a big difference (about 1.5 db)!!<br>This has now been fixed in the new version of chan_usbradio<br>that will appear on the SVN this afternoon after about 3:30 PM PDT.<br><br>Also, because of changes made in the squelch processing<br>a few months ago (hysteresis was added), the squelch<br>turn-off point is at least 60 'RSSI units' (whatever they are)<br>higher then the signal level. Its probably a good idea to set<br>the rxsquelch level to 80-100 higher then the level with no<br>signal.<br><br>This should both fix and explain a lot of strange things going on.<br>I dont think this deals with some of the weirdness with 12.5<br>kHz receivers, but it might at least help in this area.<br><br>JIM WB6NIL<br><br><br><br><br> </body>
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