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[TenTec] "A low vswr will kill you ! "

To: <tentec@contesting.com>
Subject: [TenTec] "A low vswr will kill you ! "
From: cherry@neta.com (Jim FitzSimons)
Date: Thu, 25 Jan 2001 14:00:56 -0700
Sherrill WATKINS wrote:
> 
> Jim:  I just may have a need for an end fed long wire sometime in the future. 
> I have never tried to operate with one of these antennas.  Can you give me 
> some details on your system,  balun, power level, bands operated, etc.

The wire is 362 feet long 20 feet above the ground.
The house is the counterpoise. It is sheet metal 14 feet high,
30 feet wide, and 100 feet long. The counterpoise has a wide
bandwidth.
I do not use over 400 Watts from my Centaur.
The matching transformer is made with T200-2 powdered iron toriod.
Powdered iron is better than ferrite for power but not as good
as air. It is attached on all frequencies. That helps discharge 
static.
There are four wires wound together in the transformer to maximize
coupling. 10M is on the 4:1 tap with about 2.8 VSWR. The 238 tunes
that to 1:1 easily. It does not need to be tuned. 12M is 1:1 on
the same setting of the 238. 15M is on the 4:1 tap with 1:1 VSWR.
18M is on the 4:1 tap with 1:1 VSWR. 20M is on the 4:1 tap with 
1:1 VSWR. 30M is on the 4:1 tap with the same 238 setting except 
the L network reversed. 40M is on the 16:1 tap with a 1:1 VSWR.
80M is on the 1:1 tap with a 270 pF doorknob capacitor in series
with a 1:1 VSWR 3.5MHz to 3.7MHz. 160M is on the 4:1 tap untuned
at 1.9MHz. The 238 is needed to tune down to 1.8MHz.

>  How well does your long wire work compared to other antennas?  Do you use 
> your metal house as a counterpoise to the long wire?  Have you noticed r.f. 
> on the outside of the coax?  What else makes a good counterpoise? -  Thank's- 
> Corn- k4own.

I have a MFJ 269 SWR analyzer. The VSWR on this antenna varies 
a lot over the HF bands. It just happened to have good impedances
on the Ham bands. The spacing between dips is about 1.6MHz. It is 
not as good as a beam but it is all I have.
I would like make a better antenna.
Regards, Jim FitzSimons W7ANF

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