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[TowerTalk] A4S Traps

To: <towertalk@contesting.com>
Subject: [TowerTalk] A4S Traps
From: W1JR@arrl.net (Joe Reisert)
Date: Thu May 8 11:58:12 2003
Dave,

At 07:36 AM 5/2/2003 -0700, Dave Hough, W7GK wrote:
>Recently our club got a used and disassembled A4S. There are no markings 
>remaining on the traps.

You'll have to somehow figure out the resonant frequency (perhaps with a 
grid dipper) but the TB trap is tuned near 21.5 MHz and the TC is tuned 
slightly lower at approximately 21.3 MHz. Hence, if you come up with any 
kind to resonance testing method, the TB is the higher frequency trap.

>1. how can you distinguish a 15 meter TC trap from a a TB trap.

Ditto on the TD (28.1 MHz) and the TE (29.050 MHz).

>2. how can you distingush a 10 meter TD trap from a TE trap.

Traps have a hot (open circuit end high impedance end) and a cold end 
(shorted to trap cover and element). Cushcraft prefers to have the hot end 
away from the boom. If you slip off the outer black caps on the traps, the 
end with the can bolted to the tubing is the cold end and should be on the 
boom side of the beam and vice versa.

>3. how can you determine the direction to install the 10 meter TD and TE 
>traps.
>
>Thanks for any help you can provide.

73,

Joe, W1JR


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