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I fully expect I'm in a group of one.
But especially as the QCX was first requested and now being
offered as field optimised.......
Imagine the gods gave were kind hearing the rarest of rare DX
when you trip over the feeder and it pulls out the back of your
radio, or the patch lead that was OK when you packed it away you
find is no longer.......
I know I don't want to be fudging with SMA connectors and mini
coax with minimal hand and soldering tools on a hill top or worse
still atop a ski jump.
SMA's were not "invented" to be a regularly disconnectable
connector, then add to it some dust & dirt "grinding paste"
and who knows how durable it will be on the trails.
At least some BNC's styles are available as "Solderless" that
will suffice for field repairs to get you out of trouble, even
then cable preparation can be a faff when you discover at the most
inconvenient time you have a bad cable.
in the past either by luck or by design the QRP labs enclosures
for the U3 has allowed for substitution and the drilling out &
fitting of a female shielded Banana Plug receptacle, more commonly
known as a SO239
Assembled PL259 can be reclaimed easily enough on hill tops,
although solderless and non-crimp also exist, the cable can be
remade without the need of a soldering iron for field day repairs
if need be if I have forgotten to pack a few spares......
We all have a favourite
"Shack Standard" RF Connector and like all good standards, they
are far from it......
If the QCX enclosure had what ever the preferred end up
being "RF Out" suitably separated from the next connector then we
all could pick & choose "our own" favourite SMA, TNC, SMB, BNC
Chassis socket. Or whatever........?
On 06/08/2020 14:49, Jim Mcilroy via
At one stage in my professional life I worked in a components
factory which made SMA, TNC, SMB, BNC and you name it. We also
made semi-rigid and flexible cable assemblies for space and
general aviation applications.
The network analysers we used had SMA on the ports as we
measured up to 26GHz in the day. They were good for more than 50
mate/demate cycles but they were of high quality.
I agree that TNC is a resilient connector and would like to see
it used more.
If a connector fault was reported or something sent back we
would measure what we could and if in doubt pot the connector
and section it to see how the assembly materials fared. I did
see one example of a faulty SMA where some metal of the inner
connector dislodged, made its way through the dielectric to the
outer core and short circuited.
PS BNC connectors are OK up to 4GHz
On 06/08/2020 14:39, Dave wrote:
The SMA is only rated for 50 mate/demate cycles, and that is for
the real gold plated versions. Quite a nice connector for
applications that call for a very few disconnects, like inside
There is a reason why the BNC is found on scopes and signal
The TNC is a close relative of the BNC, without the
vibration induced connection noise.
I have to admit to a preference for BNC.
What kind of issues have they seen?
The NanoVNA group
has been seeing some issues with SMA connectors.
It's too bad TNC connectors aren't more prevalent in
amateur equipment. I have some LMR cables with TNC
connectors and they really are quite robust...