[Elecraft] K3 with SignalLink - Distorted audio in SSB

[Richard Ferch]

What is your MAIN:MIC+LIN set to? It sounds as if it may be set to ON, 
so that you are getting audio input from both the microphone and the 
Line In jack. In your setup, MAIN:MIC+LIN should be OFF. When the radio 
is in Data mode (DATA A or AFSK A), MAIN:MIC SEL should be set to LINE 
IN to select the SignaLink input and mute the microphone input. In Data 
modes, the MIC control on the K3's front panel changes its function to 
act as a Line In level control. Changing MAIN:MIC SEL in Data mode will 
not change its setting in SSB, and the Line In level setting of the MIC 
control will not affect the Mic gain setting for SSB. In SSB, MAIN:MIC 
SEL will still select the correct microphone input and mute the Line In 
input provided MAIN:MIC+LIN is set to OFF.

The fact that you are having audio problems with the audio and PTT 
cables connected to the K3 but disconnected at the far end does suggest 
that the audio cables may be acting as antennas and picking up RF. If 
so, this could continue to affect your signals in DATA modes even after 
you solve your issues in SSB, and you will need to solve that. There are 
others who are better qualified than I am to deal with that kind of 
issue, but one possibility is that you may have common-mode RF on your 
feedline that is being picked up by the audio or PTT cables.

73,
Rich VE3KI


K6VWE wrote:

> I am using a SignalLink USB interface to my K3 with the cables provided by
> Tigertronics, and the FLDIGI software.  The cables from the SignalLink are
> plugged into line in, line out and PTT on the back of the K3.  Things seem
> to work fine in digital modes, although I have actually only tried the
> combination on PSK31.  When I switch to SSB, however, I am getting reports
> of distorted audio, and when I monitor my audio I can hear it too.  One
> contact said it sounded like the opposite sideband not being suppressed
> enough and slightly delayed.
>
>
>
> I have tried the following to solve the audio problem:
>
> 1.  Turning off the SignalLink when I am in SSB mode.  In this case, in
> addition to the above-mentioned distortion, I get an audio tone on my voice
> signal which can be heard by whomever I am talking to.
>
> 2. Disconnecting the cables at the SignalLink but leaving them plugged into
> line in, line out and PTT at the back of the K3 when in SSB.  This does not
> fix the problem.
>
> 3. Disconnecting the cables at the back of the K3 - line in, line out, PTT.
> This solves the problem and I again receive reports of "great audio" as I
> always have.
>
>
>
> It seems like the above symptoms could indicate an "RF in the shack" problem
> though I have not had any RF problems in the past.  My K-Line (K3, P3,
> KPA500) is all connected together with grounding strap, however the
> SignalLink box has no grounding port, so it is not connected to the other
> equipment other than with the signal and PTT cables, nor is my computer
> connected to the K-Line with grounding strap since it is about five feet
> away from the K-Line.   My CONFIG: LIN OUT setting on the K3 is NOR 010, and
> I am running the latest firmware, 4.83/2.82.