Re: NEC-LIST: EX 5 source model.

Good day Glenn,

I have modified a file for the HF Short Fat Dipole
(Antennex.com, Aug. 2004) to be in free space without loss.
I had to adjust the radius of the radiating wire (the
straight one) to 1.6 mm to get the thing to resonate near 7
MHz (7.047 MHz). Looking at the currents on the radiating
segments, its effective height is about 3.8 m, which implies
a radiation resistance of 6.3 ohms. Using either EX 0 or EX
5 I get the same resonant frequency. Using EX 0 I get
Z=5.47 ohms and average gain over the quarter sphere (2 deg.
steps) of 0.953. Using EX 5 I get Z=6.15 ohms and average
gain of 0.848. The average gain should be 1.

I like the higher resistance from EX 5, but the low radiated
power makes me apprehensive. I wish someone could report a
comparison with measurement. I don't have good enough
equipment.

Regards,
Doug

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