[TowerTalk] A new thread on connectors 8^)

[Bob K6UJ]

Terry,

Interesting information, thanks for sharing.
I am looking at an Amphenol bulkhead connector and an off brand barrel 
connector and I
see what you are talking about.  The threads on the barrel connector 
start about an 1/8"
from the end, whereas the threads on the Amphenol start very near to the 
end.
I haven't yet noticed any difficulty mating to the cheaper connector 
ends, as far as I remember
but this is good to know.  Another reason to get quality Amphenol 
conectors !

Bob
K6UJ



On 9/6/16 8:33 AM, Zivney, Terry wrote:
> A  new thread on connectors 8^)
>
> I was investigating inexpensive connectors for LMR-600 (to run up the tower
> to the different beams).  The genuine Times connectors were not considered
> initially because of the high cost of UHF connectors.  I wanted female UHF
> connectors so I could put male PL259s on the short flexible jumper cables to
> the stackmatch and antenna baluns.
>
> It seems that the crimpon tool needed for LMR600 is different and more
> expensive that the tools I have used for RG213, LMR-400, and RG8X. So,
> I ordered a pair of UHF female clamp-on connectors from W5SWL. (This is
> not a knock on his products).  The connectors arrived, sure looked great.
> But, before I put the connector on the sample RFC-600 coax, I tried
> it with a PL259 cable in the shack. To my dismay, I could not  get the
> two connectors to mate!
>
> I tried several different makes and vintages of PL259 connectors. THe
> genuine Amphenol solder-on PL259 went on only with the greatest difficulty.
> Some of the silver-plated teflon hamfest connectors would not engage at
> all.  The no-name crimp-on PL259s with the crimp center pins all worked great!
>
> Scratching my head, I grabbed a genuine Amphenol Tee.  The male part went into
> the W5SWL with no problem.  All of the different types of PL259s mated with
> the female parts of the Amphenol Tee with no difficulty.  The PL259s all
> worked with the genuine Amphenol SO239, too.
>
> Looking at the W5SWL female UHF connector, and  comparing it to the
> Amphenol females, I noted PART of the problem.  The W5SWL connector,
> like many other UHF female  connectors, including cheap barrel  connectors,
> starts the thread quite a distance from the end of the connector. Careful
> examination of the various male connectors showed the same thing. The cheap
> crimp-ons that worked with every female connector in the house have threads
> almost to the very beginning of the shell.  The genuine Amphenol PL259
> starts the thread farther back.  The hamfest specials start the thread
> very far  back.
>
> The problem is the combination of "missing threads" on the W5SWL female
> and the various males ment that there was no overlap of the  threads to
> screw the shell on.
>
> A trip to the Amphenol website to look at the specification drawings
> shows NO spec for where the  threading starts, just calling out the
> thread size.  This is true for both the PL259 and the SO239.
>
> This was the AHA! moment.
>
> I purchased an Ameritron ALs-1306 this spring to help with the DXing.
> I was unable to screw my existing jumper cables which had worked for
> years with the  Titan onto the Ameritron.  The Ameritron amp uses
> some UHF connector which is NOT an SO239, but appears to be a
> bulkhead  connector of some sort with threads looking very much
> like those on the W5SWL connector that started this investigation.
>
> BTW, all of the shells of the PL259s screw onto all of the female
> UHFs IF the center part of the connector (the part holding the male
> pin) is left off.  So, the threading size is correct, just not the
> threading position.
>
> Also, a look at phtotographs of connectors on various web sites
> suggests this problem could happen with N connectors as well, since
> the threading appears to be variable on them as well (the thread
> size is the same, and no spec is shown for the length of thread nor
> the starting position).
>
> I'm still looking for reliable information on female UHF connectors
> for LMR-600.
>
> Terry N4TZ
>
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