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Topband: questions on Slopers

To: <topband@contesting.com>
Subject: Topband: questions on Slopers
From: franknorton@home.com (Frank Norton KB8XU)
Date: Tue, 21 Aug 2001 20:05:25 +0100
Several years ago I installed 4 1/4 wave slopers around a 94 foot Rohn 45 
guyed with Phillystran. Please be kind, remember this all took place before 
resources like this reflector were available, and u were lucky if one other 
guy in the area radio society even listened to 160, little lone trying to 
transmit.

Suffice to say with all the feed points gathered at essentially a common 
node--pattern results were disastrous. What I had forgotten was the point 
or area of max radiation was indeed elevated quite nicely (compared to a 
base loaded vertical), but every antenna was in virtually the same 
spot--there was no separation--as in a 4 square, or tricorner vertical 
array. So no matter which antenna was active--the feed point had not 
moved--hence, no discernable pattern (even on the rare occasions I could 
get one of the legs to load.

Perhaps someone else found a way to make 1/4 wave slopers on 160 work off a 
single tower. If not at least this may give u some options to think about.

If u must abandon the inverted L and the 75 foot tower is ur main support 
structure, I would consider going to a separate guyed vertical for the 
transmit antenna. Unless u can afford one of those beautiful Titanex units, 
I believe u'll have to homebrew at least part of it. (I would consider 
integrating the MFJ 1792 as a starting base then top loading it...number of 
options). Alf Sommer, of Sommer Antennas makes a model T-50 which is an 
even better option...but more money. Here is the T-50 to give u some ideas: 
<http://www.sommerantennas.com/t-50.html>. Once u have reviewed all these 
and decide whether u really want to spend $500 plus on a transmit setup, I 
would reconsider the major asset u mention in the first line of ur post---> 
A nicely toploaded 75 foot vertical!

By the way I'm assuming u have already purchased a copy of ON4UN's book 
"Low Band DXing".  A reread of transmitting systems in there is always 
worthwhile. WITH UR SETUP SHUNTFEEDING THE TOWER WOULD BE MY FIRST CHOICE. 
It's cheap, and it gives u a starting system to compare any other 
installations to.

73 es gud luck de Frank KB8XU



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