[TowerTalk] RE: Crappy PL259's

[DMartin560@aol.com]

Hi Kenneth,
My comments below.
Dwayne  KG4ADM


<<  I can Second (or third) this!  The use of crimp PL259 is wonderful!
  
  I use RF Industries crimp-on connectors for practically everything...except 
  PL259's on RG58 coax, they don't make a conn for it.  I use PL259, SO239, 
 NM, 
  NF, BNC, TNC, Mini UHF on Times LMR400 and LMR240 cable...either standard 
or 
  Ultraflex.  For PL259's on LMR400 cable the center pin is crimpable but I 
 usually solder it.
  The PL259 RFI conn I use is RFU-507-SI.  You can find info at < 
  www.tessco.com >
  I don't have the model number of the crimp tool handy.
  When I HAVE to solder a 259, I only use Amphenol silver.
  Just my opinion.
 
  73 Dwayne  KG4ADM
   >>
 Not needing any help with installing PL-259 connectors I've never looked 
into 
 crimping tools and have no knowledge of them.  I'd like to know what is 
being 
 crimped?  Perhaps the center conductor can be crimped OK but how does one 
 crimp to the shield in a Pl-259?  Any pressure on the shield will not be 
 supported by the dielectric under it.

KG4ADM-  The best way I can describe it is to Go to < www.rfindustries.com > 
, search under connectors for part number RFU-507-SI and look at a picture of 
the connector.  By the connectors design, the shield will be supported 
between the connectors inner part and the crimp sleeve.  The center conductor 
can be crimped but I usually solder it if convenient.
 
 In Type N connectors there is a rubber O-Ring seal that is pressed against 
 the outer covering as I remember for a water seal only.  This pressure 
 results in a denting of the center dielectric and eventual water leakage.  
 Other wise the Type N is a fair connector impedance wise at VHF and higher 
IF 
 the center pin pressure forward into the female part so the shoulder makes 
 continuos contact instead of just the smaller pin inside a very small 
squeeze 
 contacts.  To prevent eventual water leakage from the rear I have added RTV 
 Rubber Seal in the back if the connector and a length of shrink on tubing 
 over the rear part on to the cable or taped it if I didn't have the shrink 
on 
 tubing.
 
 One other thing about a serious deficiency of a Type N connector--in 
 particular outside in cold weather.  I had a Type N on coax with a solid 
 center conductor.  On a cold day about 35 degrees my antenna was dead.  The 
 solid center conductor "Contracted or Shrunk" so that it pulled the center 
 pin entirely from the female part in the connector on the antenna.  It was 
 originally flush with the end of the connector when originally installed.  I 
 set the shoulder back a bit inside the connector so the center pin was back 
 flush again.  I didn't check it again next summer to see where it was.  
Solid 
 center conductor wires can slip inside the coax due to differences in 
 expansion where the twisted stranded wire apparently cannot.  I'll have to 
 check that out in cold and hot weather with a test just for that with solid 
 conductor center wires in coax (which have less loss).  
 
 The Type N line of connectors relies on 3 or 4 small pressure fingers on the 
 very small male center pins which have far less contact area than the body 
of 
 the pin and reduce its power carrying ability.  This is why I say it's 
 necessary for the pin shoulder to make firm and clean contact.  Maintaining 
 this firm contact is almost impossible. This is why PL 259's have a center 
 pin contact advantage as it can't move.  I make sure the center pin has no 
 solder flow on the outside of it, otherwise clean and I even coat it 
Silicone 
 grease.  It remains RF clean.  I clean the inside of the SO-239 female 
socket 
 also regularly with a small diameter abrasive stick.  My connectors never 
 heat.
 
 Now back to the PL-259.  DeWayne what is and why do you use "Amphenol 
silver" 
 which I assume is a solder.  Regular solder works just great in soldering 
the 
 center pin and is a fairly low temperature solder.  What is the melting 
 temperature of Amphenol silver?

KG4ADM-  I should have been more specific here.  It's not a solder.  It's 
just the garden variety, but better quality, silver plated Amphenol PL259.    
 
 I recently recommended drilling the 4 holes in the PL-259 body with the next 
 larger size drill and beveling the holes for easy soldering as it also 
 exposes clean brass.  A ZL supported this practice with his post--smart guy. 
 
 Try it--it works  k7gco
  >>

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