[TowerTalk] N or UHF?

[Dan Hearn]

Roger, I have heard of problems with N connectors on the end of long cables.
There is reportedly a different thermal expansion  between shield and center
conductor which tends to pull the center pin out of the socket. Apparently
the UHF jobs are more tolerent of this. 73, Dan, N5AR

-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com]On Behalf Of K8RI on TowerTalk
Sent: Monday, October 16, 2006 1:25 PM
To: TOWERTALK at contesting.com
Subject: [TowerTalk] N or UHF?


It's just a small thing, but I'm running some LMR-600 and 5/8 Heliax up the
tower for six and two. From the rig to the antennas is roughly 228 feet.
The pigtails from the entrance bulkhead are LMR-400 UF.  I grounded the
LMR-400 cable jacket at the base of the tower using UHF bulkhead connectors
through a bracket bolted to the tower legs (waterproofed with flooded heat
shrink).

I can ground the two new cables the same way, or I can use a double female N
connector clamped to a leg of the tower. I'll be doing the same thing at the
top of the tower where the pigtails hook to the LMR-600 and Heliax.

The only drawback I can see with the N connectors is the lower voltage break
down and although they are inherently water proof/resistant that is placing
a lot of faith in a little gasket. Of course I can do the flooded heat
shrink treatment on those as well. OTOH clamping directly to a tower leg
probably gives the best angle for diverting lightning off the coax.

At six and two meters I doubt the extra loss for either type of connector is
worth taking into consideration. Due to RF exposure levels I'm limited to
380 watts key down (continuous) into the 2-meter array but at the 20% SSB
duty cycle I can still run the legal limit (when I get the amp).  I can run
the legal limit, any mode, on six.

Any one have any good reasons/thoughts for going one way or the other?

 BTW IF for some reason, some where along the line a message gets tagged as
spam *Please* remove that tag before replying as the message will get dumped
at my ISP and I'll never see it. The same is true for answering anything
with the word "Digest" in the subject. They will not come through. I haven't
received any messages with the word digest in the subject line since early
last spring.

Roger Halstead (K8RI and ARRL 40 year Life Member)
N833R - World's oldest Debonair CD-2
www.rogerhalstead.com

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