Hello I am a beginner on radio and also In speaking english. I hope you will understand what I say.

Let's say I have an impulse generator and the air gap breakdown. I am already able to see the impulse breakdown wave in my oscilloscope and it's has about 1.2 ns rise time.

I know that spark gap will radiated electromagnetic wave on a wideband of frequency.

1.Can I count or measure the wave on frequency domain? If I can, what is the tool that I need? Is it spectrum analyzer? Or oscilloscope can do that?

2.continue from Question 1, does the impulse breakdown wave that I see on my oscilloscope have a relation with the electromagnetic wave radiated from the spark gap? I see some equation that related to the rise time to measure a bandwidth, but Im do not sure what it is.

My goal is to design an antenna to detect the electromagnetic radiated by spark gap.

Once again, I hope you understand what I mean. And I am sorry if its a silly question since I really am a beginner and if you have a suggestion topic for me to learn the detail for your answer, I will really thankful! Hope you all have a great life!


1 Answer 1


You could do it with a spectrum analyzer, but there's not a lot of point to it. If you know the rise time of a current impulse, then a quick estimate is that it carries significant energy at every frequency between 0 and the inverse of the rise time, e.g. 833 MHz for 1.2 ns.

  • $\begingroup$ Of course if Ramanda has a spectrum analyzer lying around, then I'd think it might be worthwhile to connect it to an antenna and measure the spectrum radiated from the spark gap, if only to see relative signal strengths. Of course the spectrum from his spark gap won't be the same as the spectrum from lightning, and I believe a lightning detector is his ultimate goal. $\endgroup$
    – rclocher3
    Dec 9, 2020 at 22:08
  • 1
    $\begingroup$ @rclocher3 yes, if you have one laying around there's no harm in it, but I wouldn't put too much effort (or any money) into getting one for the purpose :) $\endgroup$ Dec 9, 2020 at 22:20
  • 1
    $\begingroup$ True, especially when any cheap AM broadcast receiver will pick up the noise easily, then Ramanda will know to not worry about the frequency ;) $\endgroup$
    – rclocher3
    Dec 9, 2020 at 23:31
  • $\begingroup$ Ahh.. I hope I get the notification when someone answer or comment on my post.. thanks rcloher3 and hobbs you guys answer really help me!! $\endgroup$ Dec 11, 2020 at 22:30
  • $\begingroup$ We already have spectrum analyzer in high frequency lab. But using AM broadcast received will be on my list also. Thanks!! $\endgroup$ Dec 11, 2020 at 22:32

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