Interesting comments on the cables. I was under the impression that LMR-600
UF ( ultra flex ) was plenty flexible to use up the tower including the
rotator loop area. It looks and feels heavy but does indeed appear to be
much more flexible than 1/2 heliax which one would never use for a rotator
loop. Has anyone has negative results with the 600Uf in such an application
as I have suggested I wonder? - Mike
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Roger (K8RI)
Sent: Tuesday, March 25, 2008 4:27 PM
To: Rob Atkinson
Cc: towertalk@contesting.com
Subject: Re: [TowerTalk] LMR and CNT
Rob Atkinson wrote:
> My advice--if you are considering going with LMR or CNT and the cost of a
> run of one of them, you may as well spend a bit more and go with 1/2 inch
> heliax LDF4-50 and get it over with. There's always this debate about
how
> on HF the reduced loss isn't enough to make it worth it but that's not the
> point--the stuff is almost indestructible with its jacket and solid shield
> it would probably jam a wood chipper and you'd be done with feedline
>
We all have different viewpoints. I replaced LDF4-50 with LR-600. For
my use (laying on the ground from the shop to the tower 6-pack and then
up the tower) I found the Andrew to be more fragile, (easily dented,
easily kinked, and has a much larger minimum bend radius than even
LMR-600). So once I finish all runs up the tower will be LMR-600 and the
LMR-400 currently on the ground will be replaced with 600 in underground
conduit.
I use CNT240 and LMR-400 runs from the antenna switches to the slopers.
As I use all crimp connectors I never noticed any problem, but both
cables are listed as tined copper braid over Al foil shields from the
suppliers. Neither CNT240 or the LMR cables are what you would call
flexible when compared to the RG8X family. The pigtails at the top of
the tower are currently LMR-400 ultraflex which has not proven to be all
that durable. The pigtails (with integral rotator loops) will be
replaced with Davis bury flex.
> forever. If you don't care about that go with 213. I have never really
> understood why anyone bothers with the times microwave coax. All that
>
It's good, it has a short bend radius and it's relatively inexpensive
and I find it to be very robust. The only cables that have given me
problems have been the Belden and the ultraflex versions of LMR-400.
I've had 3 runs of LMR 400 laying on the ground between the shop and
tower since last fall. They've been walked on, run over by the yard
tractor, tripped over and show no damage. Normally they'd not be on the
ground but some of this work started after the ground got kinda hard. IE
frozen last fall.
73
Roger (K8RI)
> expense for a feedline that is not all that robust.
>
> 73
>
> rob / k5uj
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