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Perseid Detection - Now Live Meteor Reports!


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1 hour ago, happy-kat said:

Is that giving the peak of activity for yesterday during the day on the morning?

It's 9 days overlaid. It starts with the count from 00:00 to 01:00 and runs through to 23:00 to 24:00 each day, so dark blue and brown show the peaks early on Sunday and Monday mornings. Dark grey is today.

There's still a raised level of activity.

image.png.628e382f31e184bb5372fa8264ca2900.png

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After setting up my ham radio receiver (with squelch turned on), I got hours of recording. This was my first time doing this, and I thought FM was the right modulation. Apparently I should've recorded in SSB...

Anyway, this is what I got, but I'm not sure if those are actual meteor radio-wave reflections, or just some noise issues: [See attached Screenshot]
Each peak sounds like this: [See attached audio file]

 

Any guesses?

Screen Shot 2018-08-13 at 11.01.58 AM.png

peak.wav

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1 minute ago, Stub Mandrel said:

I don't know! with SSB meteors sound like 'dooooo' dropping in pitch.

Can you check with the timing and see?

This recording began on 2018/08/13 10:40 PM and ended on 2018/08/14 2:00 AM (it was 03:20:00 long). I've got more recordings if that's not enough.

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I'm still getting detections, though the peak appears to have subsided from this morning for me.  This is the detection rate since yesterday lunchtime when I discovered the radio had de-tuned itself:

54545948_14thAugust.png.fe283e54bcb46f92fb4fcdc15e3a4b23.png

Shame about the equipment fault.  But useful info nonetheless.

@Coto: I listened to the audio file, but all I heard was a single very brief click.  One the otherhand, that's what I would expect for a carrier wave detection on FM.  You'll get a small, but fast decaying dc offset created by the FM detector, like a spike with a post-attack slope.  It won't carry any audio as there's no FM modulation.  The spike will be caused by the initial strike followed by the decay caused by Doppler on the signal, but the frequency change is small and very fast, so the FM detector output would would just be a click I think.  You might be able to see a reverse saw-tooth waveform from on an oscilloscope, which would help confirm if they are detections.

 

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@BiggerDigger: Thanks for the info! The single brief click is what each peak sounds like (the shorter peaks sound a bit quieter). Is there any analysis I can do, given my audio files to see if they are actual detections? My only guess would be to check timestamps, but I'm not sure if any of you, or any page online has got more precise timing than just "X meteors on the Nth hour".

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I doubt that it would be possible to correlate the times against the data that you have in it's current form.  There's no duration information on any of the events.

Try connecting the output of your .wav files to an oscilloscope (Spectrum Lab software should be able to do that) and look at the varying DC offsets coming out.  You might be able to derive a the doppler shift, if any, on the FM detector of your radio.  Bear in mind an FM detector will show a shifting DC bias when presented with a carrier wave signal subject to Doppler shift.

Armed with that, you may have some info on duration and profile of the reflection. That might be possible to correllate against other signals or detections.  But to be honest, I think it'll be a long shot due to artefacts introduced by the recording codec used to generate the .wav file.

For now though, I think all that can be said is that the clicks are consistent with what I might expect for detections using an FM demodulator.

Hope that helps,

Richard

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3 hours ago, Coto said:

You haven't marked the time of each peak (with at least minute-level accuracy), or just hourly (like you've presented on the graphs)?

I've got detections down to 1-second precision, but there is some inaccuracy in a standard computer clock. The graphs are just hourly totals.

I have so many detections it's virtually inevitable that one will line up with each of your peaks, they are from a few seconds to half a minute long. As B.D. say I agree your clicks are probably detections, but you need to use SSB to get long lasting signal from the ionisation trails which have hardly any doppler shift. It also converts the signal from the meteor head into a dropping frequency signal. FM will integrate that frequency shift into a single click.

Here's the latest update to 16:00 UTC, pretty much down to the pre-weekend level now. Today's curve is oddly smooth, I think that must just be chance:

image.png.acc1347f37f556ba87a1c04bd40c0726.png

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