[UK-CONTEST] UHF Connectors

[Ian White GM3SEK]

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