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Re: [TowerTalk] Was PayPal, Now Mast Insertion Depth

To: WA6RKN <WA6RKN@ARRL.net>
Subject: Re: [TowerTalk] Was PayPal, Now Mast Insertion Depth
From: "Roger (K8RI)" <K8RI-on-TowerTalk@tm.net>
Date: Mon, 16 Feb 2009 16:20:34 -0500
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
>
> I am installing a rooftop tower.  How deep into the tower to the rotator is 
> a good depth to go for how many feet of mast above the thrust bearing?
>   
First we really need to know how high above the roof you plan on, or 
would like to put the antenna and the size of the antenna. Then there is 
the question of whether the tower is guyed or simply a tripod bolted 
through the roof to reinforcements.  With a simple tripod or small tower 
I'd mount a small to medium tribander just above the top of the 
tower/mast.  With this type of installation just a sleeve would make a 
good thrust bearing rather than going to the extra cost or a bearing.  
Even on the big array here, I'm going to replace the ROHN TB-3 with a 1 
or 2' long sleeve. I may add another sleeve about 20' down in the tower.

Typically I like to mount the rotator down into a tower by at least 5 to 
10'. On mine it's down in about 25', but the mast extends nearly 30' 
above the top of the tower and is heavily loaded.  You can see the 
rotator motor sticking out to the left just above the bottom of the 
photo.  http://www.rogerhalstead.com/ham_files/Tower29.htm

73

Roger (K8RI)

> Thanks
>
> Joe Wolfe
> WA6RKN
>
>
> ----- Original Message ----- 
> From: "N7mal" <n7mal@citlink.net>
> Subject: Re: [TowerTalk] PayPal As a Method of Payment for Tower Parts, etc.
>
>
>   
>> Like many folks on this list I don't give a dam about pay-pal I signed up 
>> to
>> learn about towers and aerials not about some rummies using
>> paypal.............
>>     
>
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