[TowerTalk] Best Place to Buy Low-Loss Coax

NN4TT Dave Clausen nn4tt1 at gmail.com
Fri Oct 30 14:16:23 EDT 2020


A few years ago, I was working in a shop where we used Times LMR 400 coax
and Times EZ 400 NMH-X connectors which is a captivated pin / crimp ring N
male connector. Somehow, we got a roll of that Shireen LMR clone cable
instead of Times. Looked OK but as soon as I stripped it with the Times
tool and inserted it into the Times captivated connector, it was apparent
that the center conductor was ever so slightly smaller diameter than OEM
Times. Slid very easy in and out of the pin. Times fits very tight in the
connector (as it should). A sweep with an Anritsu SiteMaster showed bad bad
performance with that mixed connection as in high insertion loss and a
higher than normal SWR, especially above 700 MHz. HF sweep was less
pronounced but still there. The Times OEM cable / connector sweep was / is
much better.

I have no real thought about the Shireen cable as I refused to use it since
I only had access to the captivated pin connectors.  I would suggest using
a crimp or solder pin connector (N or PL259) with that cable if you use it
instead of a Times captivated connector. That loose connection could create
problems with PIM especially if you run high power or if you are combining
multiple bands through filters onto that one cable.

 FWIW, I have had great success with the Times LMR and crimp connectors for
years in basic commercial and amateur applications but in high RF
environments, I always used a rigid coax such as Heliax or RFS Cablewave
for trunkline and RG 142 or RG 303 for flexible interconnect jumpers such
as receiver multi-couplers, transmit duplexers and combiners and
wattmeters.

73
Dave
NN4TT

Sent from my not-so-new OnePlus 6T on T-Mobile.


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