I always thought twisting the feedline was to cancel radiation from the
transmission line. A poem appeared in QST in the late 50's. It went:
Feedline going up the wall,
Please don't radiate at all;
For if you do, then by and by,
I'll be plagued with TVI.
With TV twin-lead to a television set, the feedline is twisted to cancel
received signals on the feedline and resultant ghost images on the screen.
Mike N4NT@charter.net
----- Original Message -----
From: "Paul Christensen" <paulc@mediaone.net>
To: "Patrick A. Thompson Sr." <patrickth@mindspring.com>;
<tentec@contesting.com>
Sent: Friday, March 31, 2000 3:43 PM
Subject: Re: [TenTec] Re: Ten Tec antenna tuners
|
| >the tuner to the window feedthru plug. Beyond the window feedthru is 14ga
| >ladderline with a slow twist.
|
| What benefit is derived from twisting the feedline? Is it physical or
| electrical? From the 1920s and '30s issues of QST, I often find
| descriptions for adding "transposition blocks" on the feedline every few
| feet. This, in effect, forms a twist on the line as well, except that the
| twist is the reverse from the prior twist or transposition. If
| transpositioning the feeder was so popular then, why don't we see the
| technique discussed and used today when using balanced line?
|
| -Paul, W9AC
--
FAQ on WWW: http://www.contesting.com/tentecfaq.htm
Submissions: tentec@contesting.com
Administrative requests: tentec-REQUEST@contesting.com
Problems: owner-tentec@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|