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Topband: Top Loading Advice

To: "" <>
Subject: Topband: Top Loading Advice
From: "Chortek, Robert L." <>
Date: Sun, 17 Mar 2019 22:01:54 +0000
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Fellow Topbanders,

I just finished replacing my damaged base loaded vertical and have a question 
about the optimum amount of top loading.

A bit of background - my new vertical is a 55' #12 wire supported by a 60' 
Spiderbeam fiberglass pole.  At the top there are 2 -41' top loading wires 
running roughly at 180 degrees from each other, angling down at about 45 
degrees.  The ends are at about 25' . Since the resonant point is about 2 MHZ, 
I am still using an air core base loading coil 6" in diameter made of No. 8 
solid copper wire to bring it to resonance at 1825 MHZ.

I could lengthen the top loading wires somewhere between  4 - 10' each (and 
reduce the amount of base loading needed), but it will bring the ends to within 
about 15' and  20' of the ground.

My question is this:  At what point will lengthening the top loading wires and 
bringing the ends closer to ground offset the improvement gained by reducing 
the amount of base loading?

As it is, the antenna is a HUGE improvement over my base loaded vertical (on 
the order of 6-9 db from stations in the RBN within the ground wave).

Should I leave it alone and be satisfied with the improvement or lengthen the 
top loading wires. If so, by how much?

Thanks in advance from any advice.


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