Ian Roberts wrote:
>
>
>
>Vic Rosenthal wrote:
>>
>> Chuck Counselman wrote:
>> >
>> > Yes, I appreciate that a UHF connector must not
>> > be used where it might get wet, and that mechanically it's a piece of junk.
>>
>> I think the "UHF" connectors are great, appropriate technology for 1-2 KW HF
>> applications, as long as you waterproof them. Properly installed, there's
>> nothing junky about them. Actually, in my experience the most important
>factor
>> (after installation and coax seal), is that the so-239 be of high quality to
>> insure good contact to the center pin.
>
>The term "UHF" is a complete misnomer in discussing these connectors.
>They are strictly HF devices. VSR above around 140 MHz is too high.
>The better types use PTFE, bakelite or similar insulation (won't melt
>when heated with a soldering iron). Some Taiwanese types melt down at
>soldering temps.
>Some don't "wet" readily with solder, especially around the earth plane
>and the plating needs to be scraped off to achieve a bond. A gold-plated
>inner is probably a plus factor.
>
The main problem with both connectors is quality - but in different
ways.
With the "UHF" the problems is manufacturing quality of the cheaper
ones, as Ian says... so buy MIL-spec ones.
With N, the manufacturing quality is generally good, but there can be
big problems with the way we hams use them. When a loose-pin type of
plug is fitted without a cutting jig, the pin can wind up a long way
from the correct position, and sooner or later it will pull back or push
through. Also, we try to fit them to unsuitable cable such as 9913 where
you have to file the inner conductor and usually get it tapered and/or
off-center (yes, I know you can buy special center pins, but "real hams"
don't). All these things are failures waiting to happen.
I still have a few Ns in the 432 1.5kW setup, but those are new plugs
with captive pins and have been fitted very carefully. If they're not
OK, they let me know pretty quick, and then are replaced with 7/16.
Start looking out for 7/16 at hamfests. They used to be very rare in
Britain, but thanks to the cellular industry they quite suddenly
started to appear as surplus over the last year or two.
73 from Ian G3SEK Editor, 'The VHF/UHF DX Book'
'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.com/g3sek
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