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1. 07:44 PM - DIY ELT antenna T106-52 Core Test Data (Robert L. Nuckolls, III)
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| Subject: | DIY ELT antenna T106-52 Core Test Data |
The T106-52 cores I ordered arrived a couple days ago.
Rigged up a quick-n-dirty test jig to measure
the common mode attenuation performance over our
frequencies of interest in ELT antennas.
The plot shows two tests, one with 6 and a second
with 7 passes of wire through the center . . .
about the same number of turns of RG174 coax
that would fit thru the opening.
Emacs!
Emacs!
The 7T plot shows pretty much what one would expect
for shape. As frequency goes up, attenuation
increases to a maximum of about 30 dB then
declines as core losses begin to pollute the
quality of the inductor. At 406 MHz, we still
see about 20 dB of isolation . . . a significant
contribution to the goal of mating a coax transmission
line to a balanced antenna feed point. At 121.5 MHz
the performance would be better yet at about 26 dB.
I'll dig out the network analyzer and see if
I can get companion software installed on one
of the current stable of laptops. I've got some
copper clad ECB material I can cut up for making
antenna elements per Jim Wier's suggestion.
Bob . . .
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