[Elecraft] K3 - AFSK anamoly? No replies, try again

[Don Wilhelm]

Mike,

That effect should have nothing to do with the 1.8kHz filter.

I would go with Lyle's suggestion that it is the AGC that is allowing 
you to hear the opposite sideband of strong signals.

To give that suspicion a quick check, turn off the preamp and add 
attenuation, then reduce the RF Gain as necessary to protect your ears.
Then turn off the AGC.  Tune to a moderately strong signal such that you 
can decode it well.
Now tune to the opposite sideband.  Do you hear a significant drop in 
the opposite sideband?  If so, your AGC settings may need some work.
If not, there is a problem with the opposite sideband response in your 
K3 - reload the DSP firmware, and if no help there, contact K3support.

One other thought - did you experience this with only one RTTY station?  
If so, that one station may be operating with a Double Sideband signal, 
and what you are hearing is the same as what would be heard by any other 
station listening to that signal.

73,
Don W3FPR

On 1/7/2016 5:24 PM, Mike Murray wrote:
> Joe, et.al.,
>
> I finally got back to the shack to check the setup.  It looks like I was
> actually using a 1.8 kHz SSB roofing filter in conjunction with the 500 Hz
> dual PB DSP filter.  I also checked the filter offsets which were all at
> 0.0 (all 8 pole) and I was using AFSK A mode.  Is the effect I'm seeing due
> to use of the 1.8 filter or do I have more research to do?
>
>