The only coaxial cable (braided shield) I use are the Times LMR products or
equivalent with the LMR connectors. They have the captivated center pins...no
issues whether jumpers or cable runs up antenna supporting structures. On
hardline (non-air) the center conductor is bonded to the foam so it’s not
moving but the newer connectors have a captivated center pin as well. No
issues with thousands in the air.
We just deployed over 600 new antennas on distribution poles with two runs of
LMR-400 in our area with 4ea. Type N Male connectors at each pole just in the
area I work in...literally thousands of poles in the other states within our
company...it’s standard stuff.
We had hundreds of installations in service already with multiple connectors
per installation with no issues...
The modern N connector design is not the problem.
Now the older type N connectors where you have to go through the tedious
installation process of fanning the braid, the washers and rubber parts inside
the connector....soldered on center pin....junk...don’t use them. They have no
mechanical strength. You can quite literally twist them off. If they are
installed on a tower with any weight of the cable on them...they will pull off
pulling the center pin out of the connector. If that’s what you are using then
yes you will have problems. No one in the industry uses those type connectors
on towers and avoids them as jumper/patch cables.
Spend the money...prep the cables with the prep tools and put decent connectors
on decent cable...you will be rewarded with years of trouble free service.
Learn to properly weather protect your connectors or use 3m coldshrink
products. Any silicon grease near connectors guarantees tape won’t stick.
Never used in commercial installations except on O rings inside of hardline
connectors. Tape, mastic and more tape...or coldshrink.
Sorry for the tirade but if we adopted the stuff in common use in industry
where reliability
Is a priority we wouldn’t have these issues.
Cecil
K5DL
Sent using recycled electrons.
> On Dec 6, 2018, at 9:48 PM, Richard (Rick) Karlquist <richard@karlquist.com>
> wrote:
>
> I used to have many coax cables with factory installed type N
> connectors. Virtually all of them have sooner or later
> suffered from the center conductor pins either retracting or
> extending outward over time. Once the pin moves far enough
> either in or out, the connector will no longer mate. I have
> been able to temporarily rehabilitate some cables with the
> retraction failure by pulling on the center pin with vise
> grips. If they overextend, there is no way AFAIK to fix
> them besides replacing the connectors. Evidentally,
> none of these cables used connectors with a captivated
> center conductor. I have seen this in coiled up coax,
> coax hanging from a tower, and coax just laying on
> the ground. Coax used/stored only indoors seems to be
> immune from this problem.
>
> I would be interested in hearing from other people who have
> observed this problem. Am I somehow doing something wrong
> to cause this?
>
> Rick N6RK
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