[TowerTalk] Crimped PL-259's

[Jim Thomson]

Date: Thu, 14 Oct 2010 08:41:08 -0700
From: Jim Brown <jim at audiosystemsgroup.com>
Subject: Re: [TowerTalk] Crimped PL-259's

> Almost no one except amateur radio and CB uses UHF (PL259) connectors anymore.
>
> Therefore you will mostly find them in ham and CB shops (and ebay).
>

The inference here is that UHF connectors are somehow outmoded. 

### They ARE outmoded.  There is no standard for UHF connector's.  If there
was, they would all be useable, and they are not.  The quality of UHF connector's
varies from superb to pure junk.  A lot of them are not 50 ohms.   They can't be 70 ohms
for RG-11  and  50 ohms  for RG-213....at the same time. 



Nothing 
could be further from the truth.  The FACT is that they are entirely 
satisfactory for systems operating below about 500 MHz, and 
mechanically, they have some significant advantages over most other coax 
connectors when installed on most coaxial cables .

###  what mechanical advantages?   They are not even waterproof !  




Those other newer connectors DO have advantages above 500 MHz, where 
their constant impedance characteristic  matters, and where their small 
physical size takes up less space.

Why is so much new equipment coming with N connectors, or with other 
smaller connectors?  Mostly because that equipment operates at those 
higher frequencies, where their advantages DO matter.

### The only connector's  offered  for  7/8"  and  1.25"  heliax is 
type N... and 7-16 DIN.      Andrew stopped making   UHF males  for
7/8"  heliax back in the early 90's.  The only connector you can get 
for LMR 1200 /1700 is  type N  and 7-16 DIN. 

##  7/8"  heliax and  1.25" heliax is the 2 x  most common sizes you see
in the cell industry.   7/8"  RFS brand 7/8"  heliax with a corrugated  CU
center conductor + outer conductor is aprx $2.35 per foot...cheap. Andrew
doesn't even offer  7/8" heliax with a corrugated center conductor...only 
a  copper tube.  Ditto with 1.25" heliax. 

##  RFS also makes both 7/8"  and  1.25"  heliax  with a corrugated Aluminum
outer conductor..and corrugated copper inner conductor.   Now this stuff is all
the rage in EU/Asia/China/India..and now NA.    The 7/8"  version is aprx $1.48
per foot !  it's only 22 lbs  per 100'  [ vs  45 lbs  for LMR-1200DB] . The spec's are
99.8% as good as the stuff using CU  for the outer conductor.   Having a corrugated
center conductor  means it  is a LOT more flexible than Andrew heliax  [with it's rigid
copper tube / kink prone].   From an install point of view,  flexible, light,cheap heliax
is the way to go. Braided cables  will suck water up on their braids via capillary action.

##  The cell industry  has completely swapped over to 7-16 DIN.  All the new gen 3+4
eq is 7-16 Din. Type N is obsolete.   7-16 Dins are plentiful on the surplus market.  You can't
blow up a 7-16 Din on HF.


Methinks that the poster of this comment needs to go back to study the 
fundamentals of transmission lines.

## I did.  RG-213  won't  work from the bottom of a tower to the top of a tower on 15M,
and that assumes you have BIG stuff between house and base of tower]   Hams have been
brainwashed into thinking RG-213 + UHF connector's is some sorta 'standard'.  Have folks
ever put a wattmeter at the top of their tower's..and measured their power..... with
exactly 1 kw CXR applied in the shack ??    They will get an eye opener, and then some.     



 The ARRL Handbook and ARRL Antenna 
Book are a good place to start.

##  The ARRL  handbook and Ant book  both need a serious re-write.    Did they finally
figure out how to build a balun ? 

Jim   VE7RF  



73, Jim K9YC