[UK-CONTEST] UHF Connectors

[James Thresher]

>> One question, though: where can we get good connectors for the mid-sized
RG8-X cables? Coax connectors of all types seem to be designed for either
RG213 or RG58, so mid-sized cables always seem to end up as a bodge.

Someone may already have answered this (still catching up on emails), but
these are some of the best PL259's I've found, they are designed for AirCell
7 coax, but may fit other mid-sized cable

http://www.diodecomms.co.uk/product_info.php?cPath=58&products_id=72


James M0YOM

-----Original Message-----
From: uk-contest-bounces at contesting.com
[mailto:uk-contest-bounces at contesting.com] On Behalf Of Ian White GM3SEK
Sent: 04 February 2012 08:26
To: uk-contest at contesting.com
Subject: Re: [UK-CONTEST] UHF Connectors

Ken Eastty wrote:

>> Not from me.  The 'UHF' series has kept its place at HF for very good 
>> reasons.
>>
>Ian,
>
>Let us into the secret!  Apart perhaps from the cost difference what is 
>the 'very good reason' for using 'UHF' connectors at HF & why I've 
>hardly ever seen them used in 'commercial' installations (I'm not 
>thinking of PMR).
>

Sorry for the delay in replying... by which time, it has all been said!

Every connector series has its strengths and weaknesses. It's simply that
the 'UHF' series has *enough* good features to have kept its place as a
standard [1].

The PL-259 has by far the most rugged centre pin of all the common coax
connectors. It's big, solidly fixed in the plug body, easy to solder and
very hard to break. The main problems in the original design - the braid
connection and lack of cable anchoring - have been cured in the modern
versions. The lack of waterproofing around the ring is not a problem for
indoor use.

The non-constant impedance is not a practical problem up to 50MHz. It
usually isn't a problem at 144MHz either - everything still works, probably,
but even small impedance bumps can add together and cause confusing VSWR
readings. At 432MHz this uncertainty may be bad enough to activate VSWR
shutdown.

Other than that, the main weakness of the 'UHF' series is that there's a lot
of cheap rubbish around! So just don't buy that. Be prepared to spend a
little more for the 'improved PL259' with better cable anchoring and
generally better manufacturing quality.


One question, though: where can we get good connectors for the mid-sized
RG8-X cables? Coax connectors of all types seem to be designed for either
RG213 or RG58, so mid-sized cables always seem to end up as a bodge.



[1] If we were starting again, then we'd do it all differently; but that
isn't ever the point.


-- 

73 from Ian GM3SEK
http://www.ifwtech.co.uk/g3sek
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