[Elecraft] KAT100 Control Cable

[jferg977 at aol.com]

Comrades,
The KAT100 Manual suggests that if a control cable between the tuner 
and the K2 needs to be longer than about 2 feet, it may need  to be 
better shielded.  My continuing struggle with RFI, in a system where 
the 23 foot veritcal whip antenna feed and rfi ground meet at the rear 
of the kat100 tuner which is located about 4 feet from the k2 leads me 
to want to imporove this cable.

I had used the shielded multi-conductor which came with the KPA100 to 
fabricate a control cable about 6 feet long with the pc interface 
pigtail maybe 2 inchs long.  Initially this setup worked great on 80l, 
40,and 20 meters at 100 watts.  Then, while tidying up the installation 
to better suit the XYL, I somehow changed something which allowed rfi 
on 40 meters to invade the system at any power level much above 12 
watts.  We found that by coiling the control cable as much as possible 
given its length and the distance required to reach the tuner, that I 
could transmit on 40 meters up to 50 watts without a lot of rfi 
feedback.

I have a radioworks isolator between the tuner and the k2 and a whole 
lot of ferrites on the control and power cables to the tuner.  Power to 
the k2 is also beaded throughly.  K2 is grounded separately.

So the question is, what should I ask for to get better shielded 
multiconductor than that which shipped with the kit which by the way 
looked good to me.?

It likely doesn't make much sense to try to help me trouble-shoot the 
installation since some of you have already given me a lot of very good 
ideas.  I think I know what the variables are and will have to go 
through them one at a time and make certain that nothing has changed or 
if it has, fix it.  Or there is nothing stupi lurking in there

73,   John Fergusoin KI4NGH