Hans,
That is very strange for such a condition to be present on only one
band. Are you certain it is not also present on 20, 17 and 15 meters?
If so, that would indicate a problem with the BFO for Upper Sideband.
The USB BFO is at a higher frequency than the other BFO settings, and it
may be that the BFO signal is weak at the Product Detector when you
first turn the K2 on, and it corrects itself after a bit of warmup.
Other than that, I cannot think of any reason for that behavior.
By process of elimination for specific problem areas:
1) You say the signals are loud - that rules out the bandpass and low
pass filter areas. The only thing the K60XV does to the bandpass filter
is to add the capacitors necessary to tune to 60 meters - and that is
done through relay contacts. If that relay or the capacitors were a
problem, the signals would not be loud, but attenuated.
2) It does not happen on any other band - that rules out the BFO and the
USB filters (even though I suggested it above). The BFO is not band
dependent.
3) No other circuits in the K2 should cause the symptoms that you refer to.
I would suggest that the problem could be in your 60 meter antenna
system. Loose connections with some oxidation that could be acting like
diodes which rectify a broad spectrum of RF. If you transmit, that
connection can be "healed" temporarily allowing normal reception.
Loosen all your antenna connections and reseat them. Tighten any PL-259
connectors tighter than finger tight (use pliers to snug them up a bit
after tightening).
Sorry, but I don't have any other suggestions.
73,
Don W3FPR
On 1/7/2016 4:43 PM, Hans Bonnesen wrote:
> My K2 (# 7359) has been operating flawlessly SSB on all bands since dec 2013.
>
> Suddenly for unknown reasons reception on 5343 kHz Upper Sideband seems to act very strange.
>
> On 60 meters and on this band only signals are coming in very loudly but seem
>
> to be intermixed and dispersed over several kilohertz without any chance of hitting a proper normal SSB readability.
>
> The receiver acts like a wide open broadband receiver, but strangely enough after app 10 minutes it starts slowly to act normally,
>
> and commence to be tuneable.
>
> Where to look ?
>
>
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