[TowerTalk] minimum height

[jeremy-ca]

The 1" was somewhat tongue in cheek. However the 1' in order to clear a coax 
loop is somewhat arbitrary and not supported by actual needs.
My home made boom to mast plates are 6" to 12" tall. With a 4 el 40M KLM 
getting even 2" of clearance below the plate was a chore. I had to use some 
scrap 2 x 4's to rest it on while tightening the 4 mast U Bolts; then whack 
the wood out with a hammer; never had any cable problems.

The 20 and 15M beams are low man on the other towers and 2-3" spacing has 
proved adequate for decades.

Carl
KM1H
----- Original Message ----- 
From: <NPAlex at aol.com>
To: <towertalk at contesting.com>
Sent: Monday, July 23, 2007 12:27 PM
Subject: [TowerTalk] minimum height


>
>
> Rusty,
> I think the recommendation from WA5ZUP is the one I would  follow and for 
> the
> reason he states, adequate room for the coax to flex and not  caught on
> anything.  The 1" spacing although possible seems to me to create  a great
> opportunity for the coax to get caught between the boom to mast plate  and 
> the top
> thrust bearing hardware.
>
>
> Regards,
> Norm W4QN
>
> =============================
> I haven't seen many recommendations on  this. I've googled and searched
> eham.net to no avail.
>
> What is the minimum  height above the tower top shelf recommended for an 
> HF
> beam (KT34A, FWIW). I'm  trying to run as short of a mast as possible 
> without
> impacting performance of  the  antenna.
>
> Thanks!
> Rusty
> K0FE
>
> =========================================
> 1  inch. As long as no part of the antenna or mount scrapes the tower you 
> are
>
> OK.
>
> Carl
> KM1H
>
>
>>I haven't seen many recommendations  on this. I've googled and searched
>>eham.net to no avail.
>>
>>  What is the minimum height above the tower top shelf recommended for an 
>> HF
>
>> beam (KT34A, FWIW). I'm trying to run as short of a mast as possible
>> without impacting performance of the antenna.
>>
>>  Thanks!
>> Rusty
>> K0FE
>>
>
> Message: 5
>
> Since most  tower manufacturers spec so many sq ft, 1' above the top of 
> the
> tower.   Then mounting the antenna 1' above the top would seem reasonable. 
> The
> main  thing is to have enough room for the cable loop, so it does not snag 
> on
> anything.
>
> John
> wa5zup
>
>
>
>
>
>
>
>
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