[TowerTalk] 90 degree coax bend atop a crankup tower

Richard (Rick) Karlquist richard at karlquist.com
Thu Jun 4 13:03:10 EDT 2015


On my HDX-5106, I have a 90 degree type N elbow at the
end of a 2 foot long cable arm.  There is a Kellem
grip that holds 106 feet of 7/8 inch diameter coax
that hangs down to the ground.  The end of the big coax
is connected to the 90 degree elbow.  THe other end of
the 90 degree elbow connects to a short run
of buryflex coax that runs along the arm to the tower
where it is spriraled around the mast.  There had
to be a connector involved at the top of the tower
anyway, so why not use an elbow.  (Yes, you do need
to avoid junky coax elbows, get a quality one).

Rick N6RK

On 6/4/2015 8:09 AM, Peter Dougherty (W2IRT) wrote:
> Hello all,
> I’m using an old LM-470 crankup tower and have a question about best
> practices in cable routing. At the moment I don’t have my coax feeds bonded
> to the top of the tower. Feeds from all four antennas, after forming the
> rotor loop, are taped securely to a cable arm. They make a sharp 90° bend
> and then dangle by gravity through two more cable arms in their run to the
> antenna switchbox mounted at the base of the tower. That 90 degree bend
> cannot be good for the bundle of cables. It’s high-quality stuff that’s been
> up there for 9 hot summers and 10 freezing winters now, and I’m thinking of
> replacing it either this year or next, as money allows.
>
> This picture shows how the cables are routed at present.
> https://db.tt/Hd3R7rrI.
>
>
>
> Is there a preferred method of routing cables that doesn’t involve a sharp
> bend like that? I’m imagining there’s quite a nasty impedance bump going on
> here, not to mention the potential for physical damage to the dielectric in
> the heat and cold, etc. If I’m going to spend hundreds of dollars in new
> feedline, plus the costs of having it installed (I cannot climb, myself), I
> want to ensure it’s done to best engineering practices this time. I also
> think having the lines bonded at the top of the tower would be a Good Thing,
> as well, so maybe a way to incorporate that and a new sweep or something to
> get the cables headed downwards more gently?
>
> Thanks in advance.
>
>
> ---------------------------------------------
> GO FRC!
> Peter, W2IRT
>
>
> www.facebook.com/W2IRT
>
>
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk at contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
>


More information about the TowerTalk mailing list