[Elecraft] Re: RF Coupleing

[Geoffrey Mackenzie-Kennedy]

I had a similar isolation problem between ANT 1 and ANT 2 in my KAT100, 
discovered by accident after working somebody in EU on 15m using a shielded 
dummy load connected to ANT 2.  Replacing the bare leads between the 
switching relay and connectors with coax increased the isolation 
significantly, but I also had to add a smallish relay at the ANT 1 / ANT 2 
switching relay K18 to ground the connection not in use to achieve 
acceptable isolation on the higher bands. A DPDT relay to both switch and 
ground together with coax would of course be a better method. YMMV with the 
K3.

73,
Geoff
GM4ESD


Stewart Baker wrote on Wednesday, July 16, 2008 at 5:23 PM

David,
A very good point. Although the space is rather restricted for
RG58/U it should be possible to fit some of the smaller diameter
cable such as that used to connect between VHF/UHF PCB's.
I have some silver braided coax that would be suitable.

It would have little adverse effect over such a small length, but
might provide additional isolation.

Food for thought...

73
Stewart G3RXQ