If you are concerned about abrasion look for a product called Spiral Wrap
which is normally used to tidy up cabling. Spiral wrap is perhaps a
sixteenth of an inch thick plastic which can be wrapped around the service
loop and further secured with some electrical tape. On my tower I have a
couple of places where the service loop naturally rubs so I used a second
layer of spiral wrap. This seems to do the job nicely for me.
Because I have two small stays from the very top of the tower to an
anti-torque arm just below the tower head, I have enclosed these meter long
stays along with their turnbuckles in rectangular plastic trunking used for
electrical wiring. This trunking snaps together but I have added
additional electrical tape to keep it together. Thus I try to ensure the
service loop of RG231 rubs against a smooth surface. The service loop
itself is quite loose and perhaps a bit longer than needed but it moves with
ease.
73 Doug EI2CN
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Robert Harmon
Sent: 30 March 2011 01:13
To: K8RI on TT
Cc: towertalk@contesting.com
Subject: Re: [TowerTalk] Rotator Loop Suggestions
Roger,
I have some LMR 600 ultra flex that I will need to do a turning loop
arrangemet with.
I am wondering if it is possible to do a 3 or 4 turn coil that is in a
spiral configuration
around the mast, then there would be little abrasion Just thinking.........
Bob
K6UJ
On Mar 29, 2011, at 3:41 PM, K8RI on TT wrote:
> On 3/29/2011 4:33 PM, Paul Saville wrote:
>> I have tried various configurations for a rotator coax loop, ranging
>> from a 10ft length of coax hanging in a single loop from the boom, to
>> rg58 wound fairly tight around the mast. It seems the optimum would be
>> to drop the coax as close in to the mast as possible to reduce the
>> turning radius, but far enough out to avoid snagging. Does anyone have
>> any hints or clever suggestions?
>
> I use a 3 turn coil of Davis BuryFlex(TM) about 16" to 18" in diameter
> to get a "large" turning radius laying on the flat top of the 45G . The
> large diameter puts less bending moment on the coax. The coax needs a
> flat surface on which it can skid. Even a second rotatorshelf/acessory
> shelf anywhere between the rotator and top of the tower will work for
> the shelf supporting the loop. with the outside end of the loop going
> down one of the tower legs.
>
> With the 18" diameter I can actually get by using regular LMR-400. I've
> not tried it with LMR-600, but I assume it'd work.
>
> The coil expands and contracts with rotation rather than bending in the
> normal manner so it takes a bit if calculating, or experimentation to
> get the right length to keep the coil on the flat plate.
>
> If using any of the UF versions such as LMR400 or 600UF the flat plate
> needs to be *smooth* and I have to emphasize the smooth, as the jacket
> of the UF cables is not only sensitive to UV it is easily abraded. This
> is where the BuryFlex shines as it has a very tough jacket that is
> strongly resistant to abrasion, plus it has about the same loss as
LMR-400.
>
> 73
>
> Roger (K8RI)
>
>> 73 Paul ZL3IN
>> _______________________________________________
>>
>>
>>
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>
>
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