Roy Lewallen wrote:

Well, a scope will have a 50 ohm female connector, which should
tolerate any kind of male without damage.

That's what I was talking about earlier. I ruined the BNC inputs on
some of my older TEK scopes by using off-brand 50 ohm terminators
that were difficult to install. Apparently the male pin extended too
far into the female and spread the pins. Some cheap commercial coax
cable had the same problem. The scope bnc connectors are special and
had the multiplier contact for 10X probes, and were too difficult
and expensive to get and install.

I would often waste time debugging strange waveforms when it turned
out the problem was in the scope connector. Squeezing the pins
gently would make it work for a while, then it would come right
back.

You often see the problem on used equipment like spectrum analyzers,
sig generators and counters. Evidently someone went in with
needlenose pliers to try to tighten the legs, but instead squashed
them into a square instead of a circle. They don't make reliable
connections after that.

After discussing this, I'm inclined to get a handful of female
connectors to test the male coax hardware. If it ruins the connector
and cannot be fixed, toss it in the garbage where it belongs.

The only vulnerable connector should be a 75 ohm female connector
of the sort which has a smaller pin diameter.

I don't believe I've ever seen one of those, and you'll certainly
never see one on any commercial equipment except only possibly
some video-related units.

That's good - I don't think I've ever used or seen any 75 ohm
hardware, but maybe someone working on TV might run into the
problem.

Roy Lewallen, W7EL

Regards,

Mike Monett