[Elecraft] K3 Hi SWR when sending CW

[Vic K2VCO]

40 feet is close to one wavelength on 12 meters, so that would be a 'troublesome' length 
(a multiple of 1/2 wl).

If the choke is at the feedpoint, the feedline can pick up RF radiated from the antenna. 
Perhaps try it near the rig.

Alternatively, try adding a 10 foot piece of coax to the feedline. Or, as Ron suggested, 
try attaching a 10' piece of wire to the ground terminal of your rig. The end of the wire 
should not be connected to anything and may develop a high RF voltage in operation.

On 10/3/2012 4:50 PM, Barry wrote:
> I set up a common mode choke with 3 turns of coax through 2 ferrites, similar
> to the figure 2 on p. 18 of this document:
> http://www.yccc.org/Articles/W1HIS/CommonModeChokesW1HIS2006Apr06.pdf
> I placed it outside, near the feedpoint.  it did not change anything.
>
> Geoff, I have 20-25 ft of coax outside and about 15 feet inside.
>
> Barry W2UP

-- 
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco/