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Re: [TowerTalk] 40 meter vertical to 80 meters.

To: "TowerTalk Reflector" <>
Subject: Re: [TowerTalk] 40 meter vertical to 80 meters.
From: "Alex Malyava" <>
Date: Sat, 17 Mar 2007 17:11:34 -0400
List-post: <>
there are a few things you can do.
1 - use 2-4 wires top hat which is connected through 7MHz LC-filter
2 - put a top hat and use remotely controlled matching network to
switch the bands and match antenna's impedance on each band to 1:1
3 - same as #2, more complex matching network which needs no remote
switching, but you spend some time fine tuning it.
4 - same as #2, but choosing properly height of the mast and
number/length of hat wires you may get an antenna which you can feed
through simple serial LC network.

I am building 160-80-40 60 feet high vertical using the option #2.

#2 can be found at that page is in
russian, am not sure whether DL2KQ has english version of it, but you
can look at pictures/schematics.

#3 - bottom part of page, has 80-40 antenna.

#4 -

On 3/17/07, Lee Buller <> wrote:
>   Ladies and Gents,,,
>   Last year, I build a homebrew 1/4 wave verticle and mounted it on the 
> ground with 16 radials underneath it.  I am in the process of adding 16 more 
> radials.  The antenna is made out of aluminum tubing starting with and 1" 1/4 
> and going down to 3/4".  The length is 32 feet and with 16 radials under 
> resonates at least it is flat there...and the MFJ 259 says 
> it has imdedance of 55 ohms...R=53-55, X=3-6, Theta is 10 degress,  Works 
> good too.
>   What I want to figure out is how to had a "top-hat" to the antenna to bring 
> it down to 80 meters.  I know that the MFJ brand of verticals uses a top hat 
> loading scheme and I wonder how you calculate or figure out the capacitance 
> one would need to build something like this?  Or, is it trial and error?
>   In addition, the top of the antenna is fairly small tubing (I am afraid I 
> will bend it with to much weight or load) and I need to come down on the 
> antenna about 8 feet to install the top hat.  I guess one would have to use 
> trial and error to find the right combination of "spokes and Lenghts" to make 
> the capacitance hat.  Looking at the Handbook, it does not really have a 
> "formula" for such things.
>   Anyone have any insite?  Give me a starting point?
>   73
>   Lee - K0WA
> In our day and age it seems that Common Sense is in short supply.  If you 
> don't have any Common Sense - get some Common Sense and use it.  If you can't 
> find any Common Sense, ask for help from somebody who has some Common Sense.  
> Is Common Sense devine?
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