[Elecraft] K3 Amplifier Drive Inconsistency

[Jim Brown]

On 8/5/2019 6:23 PM, Jim Rhodes wrote:
> I
> am currently portable for work (in North Dakota) and am using a mobile
> antenna clamped to the top of a 6 ft tall wooden fence.

That mobile whip is only half of an antenna. When used on a vehicle, the 
metallic parts of the vehicle provide the other half, a path for return 
current, which is called a counterpoise. If you provide no counterpoise, 
return current will flow on the outside of the coax down into your shack.

The solution to your problem is to 1) provide that counterpoise, 
possibly in the form of one or more resonant radials (more is better); 
AND 2) put a proper ferrite choke at the antenna feedpoint so that the 
coax doesn't carry return current. See http://k9yc.com/2018Cookbook.pdf 
for detailed advice on chokes.

73, Jim K9YC