"dansawyeror" wrote in message
...
Frank,

Will you please forward the nec code?

Thanks - Dan

Hi Dan, this is essentially the initial code that I used. I have just
removed, and replaced, the "GM" card by a series of "GW" cards.

Note that John mentioned he is using a gamma match, and tunes out the
reactance of the loop on the opposite side. The diameter of the loop is a
nominal 20 ft, so it would make the most sense to tune, and feed, the
antenna on the two vertical elements. My model is 30 ft at the top, and
8.272 ft at the bottom, so even with the reduced height motorized tuning
makes a lot of sense. I am going to model a gamma match, and opposite side
tuning cap, so will update the code this weekend.

The antenna is virtually lossless, with a 99.8% efficiency, and even
exhibits quite a good low angle performance. The gain at 25 deg elevation
is 0 dBi. I have no experience with gamma matches, but if you can build a
practical model with 3/4" pipe, then I would guess its loss would be low.
Also note the input voltage is 27 kV with a kW input.

73,

Frank

Here is the code

CM Octagonal loop
CE
GW 1 9 0 0 30 9 0 30 0.03125
GW 2 9 9 0 30 15.364 0 23.636 0.03125
GW 3 9 15.364 0 23.636 15.364 0 14.636 0.03125
GW 4 9 15.364 0 14.636 9 0 8.272 0.03125
GW 5 9 9 0 8.272 0 0 8.272 0.03125
GW 6 9 0 0 8.272 -6.364 0 14.636 0.03125
GW 7 9 -6.364 0 14.636 -6.364 0 23.636 0.03125
GW 8 9 -6.364 0 23.636 0 0 30 0.03125
GS 0 0 0.304800
GE 1
GN 2 0 0 0 13.0000 0.0050
EX 0 5 5 00 1 0
LD 5 1 1 72 5.8001E7
FR 0 11 0 0 3.7 0.01
RP 0 181 1 1000 -90 0 1.00000 1.00000
EN