Date: Tue, 26 Jun 2018 08:12:52 -0700
From: jimlux <jimlux@earthlink.net>
To: towertalk@contesting.com
Subject: Re: [TowerTalk] N connector, Re: UHF (PL259) soldered center
On 6/26/18 7:18 AM, Jim Thomson wrote:
>
> ## Forget what amphenol states. A teflon PL-259 will hi pot test a heck
> of a lot higher
> than a Type N. Type N uses a puny center pin, identical to a BNC.
Actually not - .120" (N) vs 0.053" (BNC) - you're looking at that
tapered guide pin, but that's not the current carrying part.
The center pin
> on any PL-259 is huge by comparison. There is no RF on the center pin any
> way. The
> RF travels down the outside of the mating female of the SO-239.
Uh.. Current in the center conductor is equal to the current in the
shield. technically, current in the outer surface of the center
conductor matches the current in the inner surface of the shield.
### Hi pot test a PL-259 vs a male...type N.
## There is NO rf current flowing on the outside of the pin of either a
type N nor a PL-259. The current instead flows down the outside of the
mating female cylinder that the pin plugs into. The center pin, or guide pin,
is just used
to mate the bottom end of the type N to the bottom end of the mating female
cylinder it plugs into...
which both have the same diameter. I was not referring to the inner surface
of the shield.
## PL-259 pin is 30% bigger diameter than a type N pin. Circumference is
also 30% bigger.
Which means the PL-259 will handle 30% more current. 30% more current = 69%
more power.
But the actual current is flowing down the outside of the mating female
cylinder..which is also 30%
bigger diameter in the case of a SO-239.
## although Teflon coax, like RG-393 will handle a lot of heat, you still
have to be careful with soldering the
center conductor on the coax male plug end. They really should be silver
soldered to take full advantage of the
teflon coax. Ditto with whatever is soldered to the mating chassis
female..assuming teflon is also used on the female.
## I crimp the shields when using 7-16 Dins with stuff like LMR-600 +
RG-393...using the crimping tool.
LMR-1200 uses an expanding ferrule on the inside of the copper center tube.
The braid is clamped.
Jim VE7RF
Jim
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