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Owen Duffy · June 29th 09, 07:37 AM posted to rec.radio.amateur.antenna

dykesc wrote in news:6c2bff9b-583d-4eb5-90fb-
:

You have two parts to your model, and they are disconnected (apart from
conductor coupling effects). You have complicated your model with your
counterpoise concept and it doesn't work.

Try a simple model with not more elements than necessary, then when you
have it working, current look rational etc, extend the model.

Hint: the TL element models the differential mode of the transmission line,
and NOT the common mode. To answer your original question, you do not need
to model differential mode TL, just put the source(s) up in the centre of
the dipole.

You do need to know the common mode impedance of your 4:1 transformer to
include it in the model. If it is a voltage balun, you can probably treat
it as zero ohms without introducing great error, but if it is a current
balun (as your mention of choke implies), you need to know its impedance at
the model frequency.

Owen