"Richard Clark" wrote in message
...
On Sun, 21 Nov 2004 23:24:45 GMT, "Frank"
wrote:
so half inch spacing is probably closer to the correct dimensions.

Hi Frank,

Well, my wires were separated by nearly three times that, it was
suggested by a warning window that it should have been 6" and all this
is immaterial to the design being Zip cord.

OK, so we proceed with an antenna that is "like" the topic, but is
spread out to attend to the modeler. I took all wires and separated
them by those 6" and did a SWR sweep from 2 to 30MHz by 0.2MHz and
EZNEC plunged on through them all without clutching up.

Results are
12 +j550 Ohms at 2MHz -11dBi @ 10°
resonates below 80M -6dBi @ 10°
1975 -j160 Ohms at 60M -4dBi @ 10°
570 -j890 Ohms at 40M -0.7dBi @ 10°
104 -j680 Ohms at 30M 1.1dBi @ 10°
440 -j610 Ohms at 20M 5.5dBi @ 10°
210 +j1300 Ohms at 17M 7.7dBi @ 10°
420 -j520 Ohms at 15M 8.2dBi @ 10°
173 +j404 Ohms at 12M 10dBi @ 10°
330 -j360 Ohms at 10M 10dBi @ 10°

73's
Richard Clark, KB7QHC

Hi Richard:

I have modeled wires separated by 0.5" as transmission lines, and gotten
good agreement with the predicted impedance. Only problem, with an antenna
of this type, is you exceed the 2000 maximum number of allowable segments.
I think I can go to 2" spacing, with 2" segmentation, and will give it a
try. I suspect I will get results very similar to yours. I also suspect --
but have yet to verify -- that these antennas will behave pretty much the
same as a conventional dipole of the same overall length. Note that a 140
ft dipole resonates at 3.34 MHz.

73,

Frank