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Thread: Max RF power for typical BNC connector?

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  1. #1
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    Default Max RF power for typical BNC connector?

    What is the maximum RF power that can be passed through a typical BNC connector?

    A web search didn't turn up any answer.

  2. #2
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    Licensed since 1977

  3. #3
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    Quote Originally Posted by PA5COR View Post
    Thanks.

    So, if my understanding of that info and my math is correct, 100W at HF frequencies shouldn't be a problem...

    Patrick

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    Absolutely no problem.

    But stick to a good brand and quality connector.
    A BNC is dimensionally almost exactly the same as a N connector so far as the areas that carry current and voltage, so it is good to a kilowatt or more safely.
    Not that i would ever do that to be honest, but 100 watt is no problem.
    The cable connected to it is the real problem.

    If you question this, look at the pin size of the BNC and compare it to a 50 ohm N connector. They are nearly the same.

    Look at the spacing between the pins and the "shield area" of the connector, and they are almost exactly the same.

    As a matter of fact, a type-N 50 ohm male will plug right into a BNC female and make a good connection although it won't latch. I use male "N" as quick connect to female BNC's, and male BNC's with the bayonet removed as a quick connect to N female!!! You just barely have to tweak the shield contact to make it work.
    Licensed since 1977

  5. #5
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    200W on HF is no problem, 100W on 2m is no problem either.

  6. #6
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    Quote Originally Posted by OH2WW View Post
    What is the maximum RF power that can be passed through a typical BNC connector?

    A web search didn't turn up any answer.
    The mil spec for the BNC states an rms max voltage of 500 volts up to 1 GHZ. The math ( E squared / R ) says 5000 watts. Which I find hard to believe. I suppose if the source and load Zo is truly 50 ohms that could be true. I do know that Navy gear in the '60's used BNC connectors up to 500 watts.

    73, walt

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    I've run 300 watts through them on 2 meters and UHF - no problems.

    My dad had a set of surplus power supplies that used BNC's for DC power connectors. I suspect it was for the high voltage capability. I think the supplies put out 150 or 200 V at up to 1 A. The connectors were never an issue, and I'd say if it was good enough for the military, it's good enough for me, even if it is very strange.
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  8. #8
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    Motorola uses them on their Micor base station power amps at VHF and UHF. Those amps were rated at 100+ watts continuous duty.

    I once wanted to test a Micor UHF PA, so i put it on a wattmeter and dummy load and attached a 1 watt exciter to it.

    Keyed it up for 24 hours straight, came back and PA was quite hot, but still putting out 100 watts.

    If the BNC connector can handle that sort of use at 450MHz, it should have no problem doing many times that in intermittant amateur service at HF.

    Joe
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  9. #9
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    A properly constructed BNC connector can withstand 500 watts at HF. This is for a matched condition of 50 ohms. Keep in mind that the BNC is typically used in UHF and SHF systems that run a couple of hundred watts. That is more electrically stressful than HF. But just to be on the safe side you should keep the RF power below 500 watts RMS.
    I'm sorry you don't have the experience or understanding to realize that others possess a skill set that you seem to dismiss as fantastical.

  10. #10

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    Quote Originally Posted by K0RGR View Post
    I've run 300 watts through them on 2 meters and UHF - no problems.

    My dad had a set of surplus power supplies that used BNC's for DC power connectors. I suspect it was for the high voltage capability. I think the supplies put out 150 or 200 V at up to 1 A. The connectors were never an issue, and I'd say if it was good enough for the military, it's good enough for me, even if it is very strange.
    150-200 Volts is "High Voltage?"

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