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Amateur Radio / Re: UNID FT8 6925 USB 0310 UTC 11 MAR 2024
« on: March 24, 2024, 0827 UTC »
If you are using some sort of LNA/pre-amp before all three receivers, then it is possible that you were hearing a mixing product/spur being generated in the LNA. However, if you aren't using an an LNA, then the fact that three receivers (all with three different dynamic ranges and input intercept points and at least two different receiver architectures, etc.) all heard it makes me think something else was going on.
Another thing to note, the thermometer below is red for a reason. It indicates that you had your audio cranked WAY up. Bad things tend to happen when you do that in WSJT-X. I find that I start to lose decodes and weird artifacts appear (which is exactly what we are talking about) if the receive audio is turned up enough that it averages 70 on that thermometer scale. I don't want to think about what 90+ means. Try to keep it between 40-60 on average and in the green.
I did see/hear some CW with an actual DX ham callsign briefly in roughly the 6930-6950 area about a month ago. I checked it on an SDR and it was there too. I assumed something was wrong with the op's TX because I only heard one side of the conversation. I went about my business and it disappeared after checking back an hour later. I forgot to write down the exact details. I think the op was Greek and I vaugely remember this happening during a contest weekend.
Another thing to note, the thermometer below is red for a reason. It indicates that you had your audio cranked WAY up. Bad things tend to happen when you do that in WSJT-X. I find that I start to lose decodes and weird artifacts appear (which is exactly what we are talking about) if the receive audio is turned up enough that it averages 70 on that thermometer scale. I don't want to think about what 90+ means. Try to keep it between 40-60 on average and in the green.
I did see/hear some CW with an actual DX ham callsign briefly in roughly the 6930-6950 area about a month ago. I checked it on an SDR and it was there too. I assumed something was wrong with the op's TX because I only heard one side of the conversation. I went about my business and it disappeared after checking back an hour later. I forgot to write down the exact details. I think the op was Greek and I vaugely remember this happening during a contest weekend.