[NLRS] Coax to antenna feedpoints: an unbroken run or a rotor loop transition connection?

[Dr. Gerald N. Johnson]

Coax that is flexible has a stranded center conductor and so a bit 
higher loss than coax with a solid center conductor. For a tall tower 
that can justify using near rigid coax for all but the rotor loop. Even 
in LMR400 that's true. Use N connectors and use the type with a captive 
center pin. Else tension and thermal extraction will retract the center 
pin on the male and break the connection which often affects receive 
much more than transmit because even a microinch gap attenuates receive 
seriously and low power transmit arcs over that tiny gap. The classic 
UG-21 family are NOT captive contact. UG-1185 is captive contact.

73, Jerry, K0CQ

On 8/27/2015 11:19 AM, David Palm wrote:
>
>
> I have new antennas to put up for 50/144/222/432.  I may have time to get
> them up before the September contest.
>
> My question is whether most of you run an unbroken cable all the way from
> your lightning arrestors to the feedpoint of the antennas (with enough
> extra at the top to create a rotor loop), or whether you do a run from the
> arrestors to a junction box at the top of the tower, then transition to
> shorter rotor loop sections to the feedpoints?  It's an additional hassle
> and some loss involved in the second scenario, but now I'm thinking that in
> terms of being able to service individual antennas it would be nice to be
> able to disconnect them at the top of the tower and have only a relatively
> few feet of cable to wrangle with.
>
> Your thoughts would be helpful, as this will all be happening quite soon.
>
> 73,
>
> David  W9HQ
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