With all filter in place and with several checks on configuration and reloading
the radio's firmware I had no success in getting out any more then 2 watts out
max on FM.
I removed the FM filter and replaced it with a .001 UF capacitor. I was
successful in putting out any amount of power I selected on FM. I monitored the
transmittion and it produces a very clean FM signal. So either there is
something wrong with the filter or RF Board.
Any comments (constructive please).
1) Move an SSB filter to position #1 and see if Tx/Rx is nominal. This
will tell you if the RF board is OK.
2) If it is, put the SSB filter back and re-install the FM filter.
3) If you have a sig gen or source of very stable amplitude signal, turn
AGC off and use the AFV function and record the level in SSB mode coming
through the SSB filter. Signal needs to have a good S/N but not be more
than S9+5 or so to be sure hardware AGC doesn't interfere with the
measurement.
4) advance to the dBV position on the VFO B display and you'll see it
bobbling around +/- 0.1 or 0.2 dB.
5) Enable the FM filter for SSB and then tap XFIL to switch to the FM
filter. You'll then see the relative attenuation of that filter vs your
SSB filter.
In my case, the 2.8kHz, 6.0 kHz and 13.0 kHz filters are all within a
tiny fraction of a dB of each other at an audio pitch of several hundred
Hz and a good S/N . Sig Gen was at -80 dBm, or 22 uV.
---
The AFV and dBV function of the K3 makes it possible to do some pretty
accurate measurements. You can determine MDS, see filter attenuation
and be sure your filter configuration loss compensation values are in
fact correct instead of guessing, etc.
73,
Lyle KK7P
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