dykesc wrote:

Thanks Roy. You've pretty much confirmed what everyone else is saying
regarding feedline radiation. Hadn't thought about the induced
contributor from the asymmetrical configuration. So a 90 degree
feedline takeoff in this situation would still result in induced
current it would appear.

Yes, that's correct. And sometimes a single common mode choke (current
balun) can actually make it worse by forcing near-zero current at a
point favorable to the current distribution.

I added a wire simulating the radiating
feedline conductor in my EZNEC model. It appears from the FF patterns
it may be helping in some directions.

It may well be. But in order to really know what the common mode current
will be, you'll need to accurately model the entire path to the Earth,
because that path (length and orientation) determines the common mode
current distribution.

While I've got you, is there any way in EZNEC to add an RF ground
counterpoise at the source end of my model? I have a long wire at my
common equipment ground point to better enable RF grounding on my
equipment and would like to see if EZNEC can tell me anything about
its effectiveness. I can't figure out how to tie the wire in to only
the ground side of a source. I read up on split sources but still
can't be sure I'm doing this correctly.

The way to do it is to put your (conventional, non-split) source on the
end segment of the counterpoise wire, and connect the transmission line
end to the same segment, rather than using a virtual segment for the
interconnection.

Roy Lewallen, W7EL