A source and load placed on the same segment are always connected in
series. The only ways in EZNEC to simulate a coil in parallel with a
source a

1. Construct a physical model of the coil using wires (if it's an air
core coil), and connect it appropriately using wires.

2. Make a small loop of three or four one-segment wires. Put the source
in one leg of the loop and a load in another. This is a bit tricky, and
doesn't always work -- NEC doesn't like small loops, so there's a
minimum practical size. But if the loop is too large, the wires it's
made from add reactance and radiate. You might or might not be able to
find a size which works. This is one of the very few situations where
the double precision calculating engine of EZNEC+ might be an advantage,
since it'll tolerate loops which are a bit smaller than the standard
engine. You should run an Average Gain test on the antenna to make sure
the NEC calculating engine isn't getting unhappy with the small loop.

But as some others have commented, it's much more common to take care of
the capacitive reactance of a short whip with a series, rather than
shunt, inductor.

Roy Lewallen, W7EL

Al Lorona wrote:
Hi, Everybody,

A short vertical such as for mobile use is capacitive and this Xc is usually
tuned out with a shunt coil at the feedpoint. Yet, when I model this with
EZNEC I cannot simulate this effect properly. I must be doing something
wrong. Does anyone have an EZNEC example showing a shunt matching coil
inserted as an EZNEC Load at the feedpoint that they can send me?

Thanks very much.

Regards,

Al W6LX