Posted by
Don Wilhelm-4 on
Aug 10, 2007; 11:26pm
URL: http://elecraft.85.s1.nabble.com/K2-KSB2-Signal-Loss-through-SSB-filters-tp451229p451233.html
Dick,
If I understood correctly: You changed the crystals and checked it and
found all was OK. Next, you changed the caps and afterward it was not good.
If the above is correct, then there is a problem with the caps or your
installation of the caps. Check them again.
If the diode switching worked before, it should be working now, and the
fact that the CW filters are OK says that at least half of the switching
mechanism is working. You did not change any of the diodes - but you
did make changes *near* the diodes, so check the entire filter end of
the board for something that you may have inadvertently disturbed. You
could check the small toroidal RF Chokes, but usually if they are a
problem they will kill receive through both the CW and SSB filters.
It might be wise to have someone else check the capacitor values for you
- often a new set of eyes will find things that you may have overlooked.
73,
Don W3FPR
Lamb, Dick & Judy wrote:
> I'd appreciate help diagnosing loss of signal apparently through the SSB
> filters in the KSB2 board.
>
> Everything was working fine with my K2 Serial # 2195 until I upgraded it
> with new crystal filters and the SSBCAPKT mod to increase the SSB
> bandwidth to 2.6 KHz.
>
> I first replaced the crystal filters in the SSB board and tested it.
> Everything still worked fine.
>
> Then I replaced the caps for the values for the 2.6 Khz bandwidth. Upon
> completion, following alignment with Spectrogram, I found t I lost
> roughly 40 db when using the SSB OPT filter. The CW filters still work OK.
>
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