It was a bit un-polite, not to report the outcome. The main problem was, that my radio equipment is running on an UPS. The 10MHz frequency GPS standard on the normal mains supply. So, I connected the frequency standard to the UPS, too. Much better, but still some hum. Tried all sorts of things, but in the end only a 1:1 transformer on the 10MHz coax fixed the problem, as suggested.
Thanks
Sorry, meant high pass filtering, of course
Hello
Am newly qrv on satellite. Everything works. Using Pluto. GPS controlled 10MHz reference, 25MHz and 40MHz phase locked loops for LNB and Pluto. Console software.
However, there is a slight warble on the audio, especially noticeable on cw,
Looks to me like a 50Hz FM modulation. No amount of notching or low pass filtering makes any difference. If I look at the audio waterfall in fl digi, two lines can be seen to each side of the signal, about 50Hz apart. This audio comes straight out of the computer like that.
If it is mains hum, where does it come from? All power supplies are switchers, so no 50Hz from them. Has anybody had a similar problem?
73
Frank
