On Wed, 30 Sep 2009 13:51:26 +0000, Rick Stealey wrote:
>Ask yourself this, "How do I know it works quite well? Could it
>possibly have 3,4,5 db of excess loss and how would I know?"
YES! Several years ago, I experimented by hanging an end-fed
vertical dipole for 40M in a tall redwood. My real purpose was to
blow up some coaxial chokes that I was using as an end insulator,
and I did it by transmitting at legal power until I saw the SWR
change.
Of course, I also wanted to test its effectivness as an antenna. I
asked for signal reports, and since I was running a full gallon,
they were always glowing. Then I switched to one of my horizontal
dipoles that were the same height as the top of the vertical one.
Each time I did that, the response was the same -- what did you
do? Your signal came up 10 dB!
>So the configuration is - signal generator, coax from the shack,
>balun, balanced line, balun, coax back to the shack, HP power
>meter. Coax loss was accounted for. The results on 21 MHz:
>1). Loss in open wire - 1.3 db
>2). Loss with 320 feet window line substituted - 0.8 db
>3). Spray 100 feet of the window line with a hose - 1.3 db
Nice work, Rick! And how much of that loss was in the baluns? :)
BTW -- one of my summer jobs growing up in southern WV (near
Huntington) was rigging TV antennas on the sides of mountains.
73,
Jim K9YC
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