"Tam/WB2TT" wrote in message
...
John,
I had breakfast with some friends this morning. One of them has a PHD in
EE, specializing in antenna design. He thinks the antenna should work, but
suggested changing the spacing between the upper and lower conductors. He
also told me to look for multiple resonances. I just now tried that, with
the spacing essentially 0. What I got was a new resonance at 165 MHz, with
Z=18 + j0. . Interestingly, I now seem to have hit parallel resonance,
like you did, and R goes down either side of 165. In fact, accross
100 -150 MHz the Z is 0 -jX. When I was messing around with spacing, at
one time I got 202 + j0 at 129 MHz; but that is way off calculated
frequency. I probably should not be doing this inside, as it is not
entirely repeatable.

I also tried a longer piece of coax (RG8X, Vp=.75) that gave me a 5 foot
folded dipole. That should be resonant at about 93 MHz. I clearly got
multiple resonances:

F R X
92.5 3 j3
100 11 j44
110 80 j181
120 4 j30
127 4 j1
160 53 j14 SWR=1.3
170 11 j0

The feedline was also 5 feet, since I did not know what a wavelengt was
going to be. This looks like it wants to be a 160 MHz antenna, instead of
93. Lastly, I tried the 5 foot antennawith a 2 inch feedline.Resonance was
at 156 MHz. If I get a chance, I will try it outdoors tomorrow.

Tam/WB2TT


Thanks for the hard work, Tam. I'm not sure I know what to make of all this,
but it appears that the antenna is not what I thought it would be.

Thanks again.

John