[time-nuts] GPS antenna installation problem

Alan Melia alan.melia at btinternet.com
Mon Mar 2 10:43:25 UTC 2009

Hi Hal, No, not as far as I know, and it is only intended to happen for a
short (stub mast) distancce. The method I would use is to cable cleat two or
three pieces of cord (use two or three cleats "in series" over 2 or 3 inches
of jacket) on the jacket/sheath before dropping the cable down the tube.
Support the weight of the cable on these....it will depend on your fixings
etc....you may need to drill small exit holes or slots for the cord exit.
Fasten the cords to take the weight, keeping the strain off the N-type brain
clamp. Messy but essential.

The used of adhesive shrink-sleeeving on the N-type body and the sheath my
also give some extra support. The sheath and braid will stretch inder the
weight whereas the inner and inner dielectic will not, this is what causes
the pin whidrawal. I believe.

How much cable will a connector support??....none in my opinion!! The creep
will just take longer! Practically maybe a couple of feet, it depends on the
stiffness of the sheath material.

Another thought is that if you are using heavy cable like RG-8, force it
back up the mast an tie-wap it at the bottom as well. This wont work with
RG-58 though.

Richard, crimp connetxors dont solve the problem either because the weight
is supported on the braid. They need adhesive shrink as well to provide
jacket to connector-body support even in normal applications. I have
repaired a lot of crimp connector systems that have failed this way, just
under flexing and not any weight. I think it is what gives the system a bad
name in some quarters.

Alan G3NYK.

----- Original Message -----
From: "Hal Murray" <hmurray at megapathdsl.net>
To: "Discussion of precise time and frequency measurement"
<time-nuts at febo.com>
Sent: Sunday, March 01, 2009 11:50 PM
Subject: Re: [time-nuts] GPS antenna installation problem

> > Take the cable down and remake it, add strain relief,  and all will
> > probably be well.
> Is there a standard trick for how to do the strain relief when the antenna
> setup to have the cable go up the inside of the mounting pipe?
> ---------
> Thanks everybody for all the roof/antenna hints from a week ago.
> --
> These are my opinions, not necessarily my employer's.  I hate spam.
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