[Elecraft] K3: reduced PWR in Data Mode on 10m only

[Don Wilhelm]

Bob,

The best current mode chokes I know about are the ones you can make 
yourself - featured in Jim Brown's K9YC Tutorial on RFI.  See 
http://audiosystemsgroup.com/RFI-Ham.pdf  See page 29 for some photos.
You can get the FT240-31 toroid cores from Diz at 
http://www.partsandkits.com/
You may want to put them at the antenna feedpoint, and if still problems 
put another at the shack entry point.  If your feedline runs away from 
the antenna perpendicular to the radiator for at least 1/4 wavelength, 
you may not need the one at the shack entry, but if the antenna is an 
off center fed, it will likely be necessary, those antennas are RFI 
generators.

Jim's document also deals with other ways of dealing with RFI, but the 
first step IMHO is to get chokes on the feedlines which can kill RFI at 
its source.

73,
Don W3FPR

On 4/18/2014 8:08 AM, Bob KD7YZ wrote:
> On 4/17/2014 23:02, Don Wilhelm wrote:
>> If all is OK into a dummy load, then the K3 is OK, but you have
>> RF-in-the-shack issues to resolve - add current mode chokes to your
>> antenna feedlines.
> Off-Hand,  can you, or anyone,  suggest which ones might suffice for my
> RG213 coax?
>
>