[K3]Sub problems cropping up

[Jim AB3CV]

I've had the sub installed for about 2 weeks and it seemed to be
working as expected. I've only been using CW and headphones. Although
I have a 1K filter in the main for now I've disabled it leaving the
sub and main both with 250 and 2.8K 8pole filters only in slots 5 and
2 respectively.

Tonight however the sub audio output is significantly lower. I've
checked and the sub is using the Ant1 input. If the receivers are
linked and the sub is on the audio is shifted toward the main. If I
turn the sub off the audio is centered between the L/R so it's not my
ears, audio amp or headphones causing the loss.

Tonight may have been the first time I checked 40m operation and I was
surprised to find 40m nearly dead on the sub when the 250hz filter was
engaged. As I raise and lower the RF gain (set to adjust both
simultaneously) I find the sub in the right channel loses all band
noise long before the main in the left ear.

All AGC settings have been returned to factory defaults which I
presume affects main and sub simultaneously.

Weak signals appear in the main (left) channel only, stronger ones
appear in both channels but always favoring the main (left.) I suspect
once the sigs are strong enough AGC on the main/sub flatten them to
nearly the same level. Turning off AGC seems to reduce the imbalance
but it is still favoring the left channel.

Also when I lower the RF gain all the way down and turn up the AF (I
have AF gain set to high) I can hear some squealing in the right
channel along with some "white noise" that isn't there in the main
(left). I also notice that with the RF left all the way down if I open
the bandwidth all the way open on the sub and the main I can hear
signals apparently blowing by the filters and producing audio and
there is nothing on the main.

I connected the XG2 and did a RF gain calibration on both receivers
and results are still the same. Although I did the cal on 40m I
couldn't find any information indicating that RF gain calibration is
band specific.

Any suggestions on what to try next?

tnx

jim ab3cv
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[Bill W4ZV]

Jim AB3CV wrote

Tonight may have been the first time I checked 40m operation and I was
surprised to find 40m nearly dead on the sub when the 250hz filter was
engaged. As I raise and lower the RF gain (set to adjust both
simultaneously) I find the sub in the right channel loses all band
noise long before the main in the left ear.

1.  To ensure that most RX settings are identical between Main and Sub, double tap A>B which will send most Main settings to Sub.  

2.  You said you checked that you were on ANT1 but did you do this on 40m?  The K3 remembers antenna assignments by band so it could be it is on AUX RF on 40m.  Go into BSET, tap ANT and confirm that you are actually on MAIN for 40m.  While in BSET confirm that the PRE/ATT setting is the same as you have on the Main RX.  It's possible to set these separately and it could be you have ATT selected which would cause attenuation.  If your Main happened to be on PRE and the Sub on ATT, it would be ~20 dB difference.  Tap BSET again to exit.

73 & GL!

Bill

[Jim AB3CV]

Hi Bill

Thanks for the suggestions. I'm now working the issues with Gary Surrency.

73

jim ab3cv
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