[TowerTalk] Rotor Loop Question

[KD0Q]

Hi Gedas,

What I did was coil the bundle around the mast 3 times so the bundle winds
and unwinds, less lateral flex that way.  A 45 deg PVC elbow protects the
bundle from the top plate.

Here's a pic of the mock-up I did -
http://s171.photobucket.com/user/gathorne/media/Rotor%20Loop/DSCF0528.jpg.html

Here's the actual tower install -
http://s171.photobucket.com/user/gathorne/media/Tower/DSCF0536.jpg.html.
Zoom in and you can see the white 45 deg elbow.

73, Glenn - KD0Q


On Tue, Nov 15, 2016 at 7:25 PM, Wayne Kline <w3ea at hotmail.com> wrote:

> Hi Gedas
>
>
>     I have  in the past with multi antennas on one  mast,   I grouped the
> coaxes together  ( the most I  had was three coaxes
>
> RG 213 )  I  taped them in a loop and inserted  the  coax in a 1" id HD
> tubing/hose  .   This prevented  the edges  from chaffing the coax
>
> in the rotation .
>
>   As for hardline   to coax    I   run them just  below the  rotor shelf
> and then group the coax up one leg  into the  hose  cover .
>
>
> Wayne   W3EA
>
>
> ________________________________
> From: TowerTalk <towertalk-bounces at contesting.com> on behalf of Gedas <
> w8bya at mchsi.com>
> Sent: Tuesday, November 15, 2016 6:58 PM
> To: towertalk at contesting.com
> Subject: [TowerTalk] Rotor Loop Question
>
> I am hoping to get a better idea on how to implement my rotor loop for one
> of my towers. The tower is a 70' aluminum universal that I use for my VHF &
> UHF antenna in addition to a short rotateable dipole for 40m. The stack
> consists of: a 17B2 at ~85', a 23 elem 70 cm yagi at ~81', a 5 elem 6m yagi
> at ~76', and the 40m dipole at ~71'. I am using new Davis BuryFlex (a low
> loss RG-8 type coax) for all my loops. I have 3 runs of 7/8" heliax going
> up the tower for 6m, 2m, and 70 cm, and use the BuryFlex for the 40m
> dipole. All 3 heliax ends currently stop about 1' below the very top of the
> tower plate. That top plate BTW is a square aluminum plate with sharp
> edges. I plan to use a sawzall to cut the corners off and file them smooth
> to help lessen the chances of damage to the coax loops if they touch that
> plate while rotating the mast.
>
> Today I made my initial connections of the BuryFlex cables to the antennas
> and roughly taped all of them in place along the booms and down the mast. I
> have all 4 rotor loops tightly bundled together and held in place with
> electrical tape every foot or so. I formed the rotor loop with a length of
> about 5' and have it secured to the mast several inches below the 40m
> dipole then to the top of the tower about 6" down off the top.
>
> Here is the issue.....that bundle of 4 coaxial cables seems to be so stiff
> & easy to get twisted up into a mess it just does not seem like it will
> work well when I raise the tower back up. The tower is currently tilted
> over via a home-brew mechanism I designed & built and can work on the loop
> in comfort so I can try different ideas. I am wondering:
>
> 1. What is the best length for the loop(s) to be? And what shape should
> the loop be? I define the loop to be the lowest place on the mast where the
> cables are taped to the first place the bundle is taped to the tower top.
>
> 2. Should I separate the bundle of cables so it is not a single stiff
> "clump" of cables ? I.e., maybe just let all the coax loops droop freely
> and not be bound to each other?
>
> 3. I am able to change where the ends of the heliax ends up near the tower
> top....how far off the top should the heliax end to make the best rotor
> loops?
>
> Appreciate any thoughts and ideas you may have.
>
> Gedas, W8BYA
>
>
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