[Elecraft] New KAT500 pics from the Visalia DX convention

[hawley, charles j jr]

I once bought a non Ampenol right angle UHF adapter which became intermittant. I found a spring inside it making the corner instead of the Amphenol method of two silver plated rods, one screwed into the other at right angles.

Chuck, KE9UW
aka Jack, BMW Motorcycles

________________________________________
From: elecraft-bounces at mailman.qth.net [elecraft-bounces at mailman.qth.net] on behalf of Jim Brown [jim at audiosystemsgroup.com]
Sent: Tuesday, April 24, 2012 10:53 PM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] New KAT500 pics from the Visalia DX convention

On 4/24/2012 8:07 PM, Don Wilhelm wrote:
> Below 100 MHz, the UHF connector is perfectly adequate.

The notion that PL-259 and mating SO239 connectors are not good at VHF
(and even low UHF) because their impedance isn't close enough to 50
ohms  is one of those myths that is not based on fact.  A few years ago,
I spliced together 1,300 ft of Commscope 3227 (like LMR400, but with a
solid #10 copper center) that cut into 100 ft lengths for a DX trip.
There were a total of about 24 PL-259s and about half that number of
barrels, all Amphenols. The loss at 500 MHz measured by substitution
using HP test gear, was a dB or so less than the published spec for the
cable.

What folks seem to miss is that 1) while there may be a SMALL difference
in the Zo, the length of the connector is also small as a fraction of a
wavelength, and 2) the tendency of loss in ANY transmission line to
bring the VSWR back to unity.  Both of these factors tend to render any
small discontinuity meaningless below 1 GHz or so.

What matters FAR more is the QUALITY of the connectors used.  Most of
the deficiencies blamed on UHF connectors (and on BNC connectors) are
the result of the use of no-name JUNK connectors.  I use nothing but
Amphenols. They cost a bit more, but I've been bitten far too often (and
badly) when I've used anything else. Nothing like having a connector
fall apart, or melt because it's made of thin metal, or because wide
tolerance parts don't mate securely, or a dielectric that melts when you
try to solder the connector.  And a junk connector that fails 80 ft up
in the air can be both difficult to diagnose and VERY costly to replace!

73, Jim K9YC
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