Don, I suggest you need to draw attention in your web page and general advice on here to the requirement to choose the AUDIO FREQUENCY with some care when setting up ALC for FT8 via the TUNE button in WSJT-X.
The problem seems to be that the DSP sampling rate inside the K3 must not be related to the TUNE frequency. Ideally I expect they should be co-prime, or something like that, to avoid aliasing artifacts in the ALC bargraph readout. The actual frequency you should choose is probably affected by PC and K3 clock frequency accuracy becasue a change of just a few Hertz can have a dramatic effect. In my case, the default WSJT-X tune frequency of 1000Hz is about as bad as you can get. My ALC bargraph oscillates with a beat frequency of not much more than 1Hz. And the ALC goes from zero to 6 bars! What is really confusing is that WSJT-X leaves the tune frequency at whatever it was when you last transmitted, so if you tune around, click on some signals, have a listen and then try using TUNE the audio frequency could be anywhere unless you take specific action. Now that I see what is happening the solution is simple and obvious. If the ALC bargraph is unstable then move the TX frequency 10Hz and it should become sane. Only then can you go through the procedure you describe to set the PC output level, WSJT-X power level and LINE level for the magical 4 solid plus one flickering bar. Of course, once you begin making FT8 QSOs and move transmit audio frequency it is entirely possible you will hit on a "bad" interaction with the K3 DSP and the ALC bargraph will be all over the place again. As far as I can see with an external power meter this ALC anomaly does not affect the transmitted signal, but I've not looked into this in detail. 73, Alan G3XAQ -- Sent from: http://elecraft.365791.n2.nabble.com/ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
