On 07/03/07 07:28 am dabneyt@vaeye.com wrote:
> Would appreciate latest thoughts re best coax type for a 55 foot
> crank-up tower with the coax and rotor cables suspended (Kellem) from
> the top stand-off--OR-- does anyone recommend attaching cables to each
> of the lower stand-offs so that the cables form a loop at each stand-off
> as the tower nests. I have not raised the tower for the first time
> yet---my understanding is that it is probably best to let the cables
> slide throught the lower loops and hopefully coil neatly on the ground!
> ... and that some types of coax not only don't coil up neatly but also
> degrade in efficiency/line-loss as the internal insulation and center
> conductor deform with movement.
>
> RF is fed to tower base by LMR-400UF. Antenna (3 el Stepp) has not yet
> arrived--several month backlog...
>
> Thoughts/recommendations would be appreciated. I have superficially
> done a search of the archives and LMR-400UF sounds like a poor cable for
> suspension and coiling.
I have the HDX-555, but the principle should be the same. I used
BuryFlex from Davis RF (www.davisrf.com) and have it suspended from the
top standoff using a Kellem Grip. When I lower the tower, I let the coax
(and rotor and SteppIR control cables -- all taped together every foot
or so) coil into a large plastic garbage can (with holes drilled in the
bottom so it doesn't fill up with water) that I bought at Sam's Club for
(IIRC) $23.xx.
I know at least one other ham who did much the same as I have done, but
I don't recall what coax he's using. One of the locals here with a
tubular tower has the cables taped to each standoff, but again I've
never bothered to ask what coax he's using.
IMO, letting the coax hang from each standoff is putting too sharp a
bend in it.
73
Alan NV8A
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