On Jun 7, 7:54*am, Owen Duffy wrote:
Jeff Liebermann wrote :

I like Thomas and Betts Snap-n-Seal connectors:

These are known generically as "compression connectors", and I
recommended the BNC type earlier, because when used with either a BNC-F
on the antenna, or a BNC/N adapter to an N-F they are waterproof, and
neither depends critically on the retaining nut torque for good
electrical connection (as do UHF, SMA and F connectors). Compression
connectors do not use a normal hex crimp tool, but a tool unique to
themselves, and in the rest of the world, the tools are pretty
inexpensive (US20).

Whilst I say they are waterproof, with force, it is possible to break the
front of the connector out of the connector body in the types that I have
tested.

If you use ordinary (ie non waterproof) crimp BNCs, you need to figure
some way to waterproof the cable jacket to the connector body. Most do
not lend themselves to glue lined heatshrink for this purpose. Of course,
you could always treat them like UHF series, and wrap the entire joint.

Owen

BNC's are still 50 or 75 Ohm. Old versions had different diameter
centre pins in order to acheive the correct characteristic impedance.

If you plugged a 50 Ohm plug into a 75 Ohm socket the larger centre
pin would splay out the female centre connector, so when you plugged a
75 Ohm back in again it wouldn't make contact. It used to be fairly
common practice to paint the body of the connector purple or green in
order to quickly identify the type and so prevent damage.

For the past 20 or so years most manufacturers have used the same
sized centre pin, but the 50 Ohm version has a PTFE skirt in order to
provide the correct charateristic impedance. So they are now
mechanically interchangeable.

UKM