[TowerTalk] How lossy are PL-259s at HF?

[Joe Subich, W4TV]

Amphenol Datasheet:
<https://datasheet.octopart.com/SO-239-Amphenol-RF-datasheet-11898728.pdf>

Unfortunately, I do not see dimension specifications for the
contacts ... only the body, threads and *internal* dimension
of the pin.

Wikipedia <https://en.wikipedia.org/wiki/UHF_connector>
gives the center pin of the PL-259 as "approximately 0.156
inch (4mm) diameter".

73,

    ... Joe, W4TV

On 6/18/2024 10:17 AM, charlie at thegallos.com wrote:
> 
> Rob,
> Totally agreed, and what eventually failed on that barrel connector
> (disclaimer, it was probably 5-10 years old)
> 
> Now here is a good technical question - WHAT is the spec for min/max
> diameter of the cup?  Rather than drag connectors (which is a good rough
> way) - I can drag a set of pin gages in a go/no go handle.  I was just
> wondering if you (or anyone on thread) knows?
> 
> 73 de KG2V
> 
> Charlie
> 
> 
> -----Original Message-----
> From: TowerTalk <towertalk-bounces at contesting.com> On Behalf Of Rob Atkinson
> Sent: Tuesday, June 18, 2024 9:16 AM
> To: towertalk <towertalk at contesting.com>
> Subject: Re: [TowerTalk] How lossy are PL-259s at HF?
> 
> I'd say when it comes to loss with UHF connectors the most critical thing is
> the machining of the male pin and the female cup fingers.
> Amphenol females are made so that you feel some resistance when you plug the
> UHF male into the jack.  That grip on the center pin is important.  Poorly
> made jacks that don't make good pin contact are where you have resistance
> and loss, so much so that in cases of 1 KW continuous duty, the jack burns
> up after several minutes.  A good jack will hold a PL259 body by the pin
> hanging down with the threaded collar loose.  If the PL259 falls out,
> something is wrong, either the male pin isn't the right size or the jack
> isn't holding it tight enough.
> 
> When shopping for UHF connectors at a hamfest, bring an Amphenol male and
> use it to test any connectors that have a UHF female involved.  Do not be
> enticed by pretty looking jacks that are silver plated with what appear to
> be teflon dielectric and gold plated pin cups.  In my experience these
> off-shore jacks may fail to hold the male vertically and will heat up if
> used.
> 
> 73
> Rob
> K5UJ
>