Here's an odd question:
Signals were booming in from ZL land tonight, so much so that 100 watts to
my TH-7 with the crankup at 50 feet here in NH got a 20-over report from a
ZL op. I didn't think it was such a big deal, but he just couldn't get over
the fact that I crushed all the rest of the guys in his pileup with only 100
watts. Half an hour later I came back to the radio and heard him talking
about how incredible my signal was to another ZL op. Sometimes propagation
really makes you look good :-)
Anyway, he insisted on knowing what kind of antenna I was using (he had a
5-element monobander at 50 feet.) At first I told him it was a TH-7 with
4-elements on 20M, but as I was saying this, I visualized the antenna specs
table in the N0AX/K7LXC study, which shows the TH-7 (and all the other big
tribanders) as having 3 elements on 20M. Bowing to the study, I corrected
myself and told him 3 elements. Then I got to thinking that I had always
thought the TH-7 has 4 elements on 20M, 4 on 15M and 5 on 10M. I looked at a
picture, and sure enough, that's what the TH-7 has (the KT-34XA does too,
doesn't it?)
So, I can only assume that the study lists the TH-7 as a 3/4 element beam
because it uses a dual-driven-element feed system. In that kind of system,
does the extra driven element not count? Is it there to improve bandwidth
only and not to provide additional gain? If so, do we only include elements
contributing to gain in the count? Certainly both driven elements are
"active" on each band. What's the proper answer to the ZL's question?
73, Dick, WC1M
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