Using WSJT-X V2.0.0-rc5 for the FT8 Roundup: 1.
A color to be used for when a station has been worked would be helpful. Instead of green for the same station calling CQ, a different color to show he has been worked would prevent calling him again. I noticed a “new call” or “new call on band” color under the colors tab of the Configuration menu. This may serve the purpose but I did not notice to check it until after the contest. Related to the colors, I had to select “Reset Highlighting” a few times to get it to stick. 2. When running on a frequency and the program auto-shifts to the calling station's frequency, and I had to manually move it to the TX frequency after I sent the “73” message. Perhaps a better way would be for the RX window to shift automatically to wherever the station is calling (including my transmit frequency) so that manual re-syncing to the TX window is not necessary. 3. I noticed several stations during the FT8Roundup contest that exhibited one or more decoded traces on the waterfall, usually when calling CQ. The stations are mostly 0 dB or stronger on their main trace when the multiple decodes appear. Each additional trace is 120 Hz below the previous trace, i.e. the second trace is 120 Hz below the main trace; the third trace is 120 Hz below the second trace, etc. I have also seen the same multiple decode behavior when the station is in QSO although not as often. I have been tracking this behavior for about a month and posted it on the WSJT-X reflector but no responses yet. I have noticed the phenomenon when using WSJT-X V1.8.0 or V1.9.1. What I've noticed recently is that the secondary decode is 12-14 dB down from the primary signal. This reminds me of the sin x/x behavior where the first sidelobe is 13 dB down. However, a follow-on observation showed the first sidelobe to be 19-21 dB down. In every case, the primary signal trace was -4 dB or stronger when the secondary lobe was decoded. If I had lab quality test equipment it would be interesting to capture and analyze this behavior. I'm wondering if the zero points of the sin x/x curve might be a clue to the 120 Hz pattern. Kind of hard to remember my math from 45 years ago, hi. As for radios used, I have K3 with the upgraded K3S synthesizer boards to provide very good phase noise cleanliness. My antenna is a Hygain 6BTV multiband vertical. (One of the local guys who has seen the secondary decodes has an ICOM 7651 which I'm sure is very clean in the RX chain.) I'm leaning toward pointing a finger at the sound card in my computer, the thought being that it may not be filtered or processed sufficiently. I have a Dell desktop with a Duo core processor running Windows 7 so it is probably ancient. (However, the local guy who has seen the same behavior has a laptop with Windows 10 and probably a better sound card.) In summary, the phenomenon is common to 75-bit and 77-bit formats. Ed, K2TE
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