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
>> _______________________________________________
>>
>>
>>
>> _______________________________________________
>> TowerTalk mailing list
>> TowerTalk@contesting.com
>> http://lists.contesting.com/mailman/listinfo/towertalk
>>
>
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|