[TowerTalk] TowerTalk Digest, Vol 69, Issue 70

[Steve Davis -Davis RF Co.]

Tnx Roger........
      Dave,  one other reason Bury-Flex Tm will work nicely on crank ups is 
that
the outer jacket (polyeth.) is denser than typically used PVC jackets (used 
on RG 8, 213, 214, many others); thus it will "slide" better if in contact 
with the metal tower... less friction..also it will settle downward/up more 
in a coiling fashion around the tower than equal diam. PVC jktd. coax.
  73,   Steve ,  K1PEK
DAVIS RF Co. , Div. Orion Wire Co., Inc.

Wire, Cable, RF Connectors and wire aerial parts.   LMR, Heliax, Eupen

Commercial / Military / & Custom Cable Design

tel:  978-369-1738     Fax:  978-369-3484
www.davisRF.com

> Message: 3
> Date: Fri, 26 Sep 2008 14:02:05 -0400
> From: "Roger (K8RI)" <K8RI-on-TowerTalk at tm.net>
> Subject: Re: [TowerTalk] Rotor Loop - How to ??
> To: Dave <dave.n7drk at yahoo.com>
> Cc: TowerTalk at contesting.com
> Message-ID: <48DD239D.8040802 at tm.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> Dave wrote:
>> I am in the final planning stages prior to the installation of a 4el 
>> SteppIR onto a 70' Trylon self-supporting tower.
>> The antenna will be positioned about 3' above the top of the tower.
>>
>>
> First: How many degrees rotation from your rotator?
> My preference (there are a number of ways to do this) I like to put a
> minimum of 2 and preferably 3 turns around the tower with the rotator
> loop.   If the tower doesn't have a flat top plate (like the 445G) I'd
> put supports on each leg at the top. I'd lay those three turns loosely
> on the top plate or supports. The coil needs to be able to expand and
> contract freely.
>> How do I prepare the coax and control cables for the transition from the 
>> rotating antenna to the fixed tower?
>> Do I fabricate lengths of replaceable cable just for the transition 
>> (rotor loop)?How do I route the cables? Multiple turns loosely around the 
>> mast like a spring? Just a single drooping loop?
>> How long should they be?
>>
> I use 3 turns of about 18" in diameter. Remember this must be able to
> move freely. It only has to hang up once to ruin the installation and
> that stuff is strong.
>> Any special coax? The antenna coax fitting is not accessible. Will 
>> Bury-Flex provide adequate service?
>>
>>
> BuryFlex should be more than adequate.
> As you can not access the antenna coax fitting and if you are running
> BuryFlex all the way I'd not bother with an extra fitting although I use
> them on my installation and I can not *easily* access any of the
> antennas.  OTOH it  might be kind of handy if you do have to take the
> antenna down.   Also if the coax fails the rotator loop is the most
> likely spot as it's moving against the tower.
>
> I'm sure others have different ways of doing it but this has worked for
> me over the years.
>
> 73 and good luck,
>
> Roger (K8RI)
>
>> Cheers,
>> Dave - N7DRK
>> Rice, WA
>>
>>
>>
>>
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>>
>> _______________________________________________
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