[Elecraft] K2 output distortion

[Don Wilhelm]

Don,

First suggestion - make certain it is an RFI problem.  Operate the K2 
into a dummy load and monitor the data transmissions with a local 
receiver - borrow one if you have to, and you may need a 2nd computer 
for that test.  You can feed the headphone output of the monitor 
receiver directly into the soundcard or even place a soundcard 
microphone near the receiver speaker to observe the decoded signal from 
the K2.

Make certain the compression setting is 1-1 and adjust your SignaLink 
output to the level just below that which produces ALC bars in the 
bargraph - increase the gain until you see an ALC bar, then back down 
until it just goes off.
If you operate SSB with compression it would be wise to activate the 
RTTY filter set and set the filters and BFOs for best operation with 
data modes.  Remember that you must set the RTTY FL1 filter to OP1. You 
can copy the FL1 BFO settings from the SSB BFO settings.  Using the RTTY 
filter set allows you to set the compression for the RTTY mode 
independently from the SSB compression setting.

OK, if operating into a dummy load does not cause the problem, then you 
can blame it on RF in the shack.  Rather than trying to fix the problem 
with ferrites on every cable, you may find easier and better success 
with using a more effective common mode choke at the antenna feedpoint 
and perhaps another common mode choke at the point where the feedline 
enters the shack.  See the fine information on RFI by Jim Brown K9YC for 
creating effective common mode chokes.  If you can keep the RF energy 
out in the antenna field where it belongs, you may not need any ferrite 
on the cables in the shack.

73,
Don W3FPR

On 11/5/2014 4:35 PM, Don Latham wrote:
> My K2 with 100 watt amp and KAT100 works very well on ssb. If I put on a
> Rigblaster or a SignaLink and MFJ switch combo, The mic always seems to get rf
> in it, or, for some other reason, the received signal is very distorted, to
> unreadability  in most cases. I've tried rf chokes on all cables, etc and that
> makes absolutely no difference. I'm going a little nuts because I simply
> cannot understand why this behavior obtains.
> Has anyone out there had this problem? What's the cause? Any hints?
>