Re: [amsat-bb] Flexible Coax

["Woody" <kj4so@xxxxxxxxx>]

Hi All:

I purchased a 500' roll of Flexi-4XL from The Wireman eight years ago.
According to the Wireman, this coax is Mil-Spec and rated for direct burial.
However, I would never bury coax directly in the ground because it is too
easy to damage the outer covering from rocks in the soil.  I always use PVC
conduit for underground runs of coax.

I moved to a new home a year ago.  I had 9 runs of Flexi-4XL that were
removed from service when the antennas were removed from an 80' tower and
three roof mounted antennas.  The coax had been in service for 6 to 8 years.
I have never had any problems with moisture in the coax like all of the
reports concerning 9913 coax.  All of the coax was used for VHF/UHF
antennas.  The 6 runs of coax from the tower were run underground to the
side of the "shack", using PVC conduit from the base of the tower, to the
bulkhead panel on the wall of the house.

Last winter, after reading more reports about water in 9913 style coax, and
also trying to decide whether or not to reuse the coax on some new antenna
installations, I decided to test the coax.  I picked three very long runs
that were approx. 120' long, and cut off the connectors that were installed
on the ends of the cable that connected to the bulkhead panel on the side of
the "shack".  The other end of the cables had been connected to PolyPhaser
lightning arrestors at the top of the 80' tower.  If there had been any
water in the coax, it would have shown up at the lower ends of the coax.
The coax was perfectly dry inside, with absolutely no signs of any water
damage.

I measured the loss at 500 MHz. on the remaining 6 runs of cable, using an
HP 8656A signal generator and an HP 435B power meter.  The measured loss on
all 6 cables agreed with the published loss characteristics of the cable.

All coax connectors were either Amphenol or Kings "N" connectors.  All were
solder-on, anvil/clamp type connectors.  These type "N" connectors use a
compressed rubber seal around the coax that seals out moisture,  UHF
connectors do not.  All connectors were wrapped with Scotch 88 tape and
coated with "Scotch-Kote" or "Coax Seal".

I do not use UHF connectors above 10 meters.  I will not use a Radio Shack
coax connector, and I will not use crimp-on connectors outside of the
"shack", or at high power levels.

The best source of coax connectors that I know of is "The R.F. Connection"
http://www.therfc.com/ .  He has good connectors at very good prices.  He
also sells the "9913" style large diameter center pins that can be used with
standard "N" connectors for the various coax with the larger diameter center
conductors.

Everyone has their own favorites, and opinions.  However, I do not remember
the last time I had a defective coax connection on a cable that I assembled,
and I have been doing this for over 25 years.

73,

Woody
KJ4SO



----- Original Message -----
From: "Kenneth M. Brockel" <kbrockel@monmouth.com>
To: <amsat-bb@AMSAT.Org>
Sent: Saturday, October 19, 2002 8:07 AM
Subject: RE: [amsat-bb] Flexible Coax


> Just a thought, Has anybody ever tried the coax from the Wireman called
> "CQ Flexi 4XL"? It is there product number #102 and I have used it for
> several now and it works great. I have never had any problems with water
> ingression or other related problems. I use this product all over my
> shack for my VHF,UHF & HF installations. If interested, check out:
>
> http://www.thewireman.com
>
> 73, de Ken, N2SMT
>
> > -----Original Message-----
> > From: owner-AMSAT-BB@AMSAT.Org
> > [mailto:owner-AMSAT-BB@AMSAT.Org] On Behalf Of Bill Acito
> > Sent: Friday, October 18, 2002 11:29 AM
> > To: amsat-bb@AMSAT.Org
> > Subject: [amsat-bb] Flexible Coax
> >
> >
> > Another "ping" to the group...  going through the ads, there
> > seems to be many, many different coax types available today,
> > and a lot of new coax "model" numbers out there (I haven't
> > really kept up since LMR400 and 9913 flex).
> >
> > I'm looking for recommendations on a flexible coax with the
> > least loss at UHF (432). It will not be buried.
> >
> > Thanks,
> >
> > Bill
> > W1PA
> >
> > ----
> > Via the amsat-bb mailing list at AMSAT.ORG courtesy of
> > AMSAT-NA. To unsubscribe, send "unsubscribe amsat-bb" to
> > Majordomo@amsat.org
> >
>
> ----
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