[TowerTalk] Open Wire line measurements

[Jim Brown]

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