Testing Coax Cable Connectors

Just a short video on how I test UHF connectors. There are some really good UHF connectors and they do not have to be Amphenol, and there are some really bad connectors.
Outside of barrel connectors, which can be significantly long in electrical degrees, I've found very little reason to go beyond close mechanical inspection and high voltage breakdown and leakage current testing.
I use UHF style connectors in my HF antenna and lower VHF antenna systems for what I think are very good reasons.

[@lifeoutwest1598]

Thanks for posting this Tom, I've learned a lot about connectors here. I had bought LMR 400 coax with Pl 259's from DX Engineering and there coax was fine but there Coax Connectors they used were so cheap, light and gave me so much failure I had to finely cut them off and buy good PL 259's and put them on the coax.

[@Jerrythenerdful]

I find high pot or high voltage testing to be more important than SWR tests on cables. :) Of course SWR is important and must be good, but a HV test will show assembly errors.

[@tonywhite846]

@@Jerrythenerdful Yes very good video. Very informative.

[@tonywhite846]

Yes. I would like to see his procedure for soldering the pl259. Which i know
would be good. His time is defenitley limited. I use mostly Crimp connectors
for the lmr 240 , 8x connectors because of heat and the foam dielectric. To
me they are just as good if not better.

[@KB4QAA]

Great stuff, Tom! Miss your participation at The Zed, but understand why. Cheers, b.

[@raymondbruns3291]

Thank you Tom for this really informative video. In the last part of the video you test a N type connector. They're you noticed arching between the inner shield and the center pin. Isn't it so that when the connector is connected that part is insulated by teflon?

[@runeye5825]

Excellent demo Tom, keep the good work very educational. Rune, LA7THA

[@barrykery1175]

Excellent demo. Thanks for posting. Barry, KU3X

[@harrisleck3960]

Tom, would you post the circuit and construction details of your HiPot tester please. Harris K9RJ

[@josemariatrueba4568]

In a 50 ohm system 1800 volts means that power is 64.8 Kw. If connector is seeing a high impedance load, then quite small RF power will developed high voltages. Only 100w may be arching 1800 volts against a 32 Kohm load.
BTW... Tom didn't tell us what frequency he was using in his tests but I'm pretty sure that arching would appear sooner the higher the frequency.

[@JxH]

HiPot is DC. At ~10kV, some your points are obviously less consequential.

[@JxH]

What's funny is I just bought some Coaxial Lightning Protectors, devices designed to arc at just moderate voltage. So sometimes the goal is the opposite. 🙂

[@SkyCharter]

9:00 Don't confuse mismatch loss as resistive "heating" loss when the loss is caused by an impedance bump.

[@Jerrythenerdful]

Mismatch loss is really just another way of expressing SWR that creates standing waves. The standing waves "stand", they do not travel. The effect of standing waves is to increase current levels and/or voltage levels along a transmission line.
I can have a transmission line of 10:1 VSWR, which is a mismatch loss of 4.807dB, and have virtually 100% energy transmission to the antenna.
The phasing harness in a collinear is a great example. If we have a 75 ohm 1/4wl cable feeding a 50 ohm element that line has a SWR of 75/50 = 1.5:1. This VSWR is a "mismatch loss" of 0.177 dB. That loss mismatch loss is meaningless. If I used Commscope RG11/U cable in the harness, the loss of that 1/4 wave cable would be 0.0184 dB or 99.58% eff, despite clearly having a having "mismatch loss" of 0.177dB. If I combined two of those cables to one point, and fed that point with a 50 ohm cable, the 50 ohms cable would have a near perfect SWR at 50 ohms. The harness loss would be twice the loss of one cable, or 0.0368 dB.
This is why mismatched cables are a standard way of splitting and combining systems, and whuy nobody cares about mismatch loss. They care about real loss.
Mismatch loss does apply when a 50 ohm generator like a standard transmitter through a large attennuator pad drives a mismatched load with no effort to correct the impedance seen at the source.
If you do not understand this, get a copy of Reflections by Walt Maxwell and read it, or build a system and measure it.

[@Brenda-jf2pe]

I think Amphinol is made in China now if I am not mistaken! I have some old ones made in the USA wonder if they are good? JohnBoyUtah KJ7TBR 🇺🇸😎🎙📡73’s