Listening to pings from meteors

[andrew....@googlemail.com]

If you’ve never heard these, then go to the link below and listen to what they sound like.

 

The sounds here are recorded by Spectrum Lab using a conditional action script to identify segments to record. The receiver is an UKRAA VLF receiver tuned to 23.4 KHz.

 

https://www.astronomy.me.uk/meteor-pings-recorded-at-lro-video-created-from-observations-prior-to-25-8-2025

 

Andrew

[Dimitry UA3AVR]

Andrew, are they from CW transmission?

воскресенье, 31 августа 2025 г. в 05:28:00 UTC+3, andrew....@googlemail.com:

[Andrew Thornett]

23.40 kHz 

Country		Station (web site link)	Transmitter (GoogleMaps link) * = high precision		kW		Remarks
D		DHO38 0000-0700, 0800-2400	German Navy - Rhauderfehn *		800		CW/MSK
D		DHO38	German Navy - Rhauderfehn *				CW/MSK

---

These are coded military very low frequency transmissions.

Andy

Sent from Outlook for Android

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From: sara...@googlegroups.com <sara...@googlegroups.com> on behalf of Dimitry UA3AVR <ua3avr...@gmail.com>
Sent: Sunday, August 31, 2025 9:10:19 AM
To: Society of Amateur Radio Astronomers <sara...@googlegroups.com>
Subject: [SARA] Re: Listening to pings from meteors

 

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[Andrew Thornett]

I have just realised I have been getting some stuff mixed up and talking a load of rubbish.....I am going demented my excuse is not feeling well this week....

So starting again:

The meteor pings are at 143.048MHz (NOT VLF sorry!). They are detected using a FunCube Pro SDR Dongle and Moxon aerial on my log cabin at about 3m height off ground and pointed SW towards Graves.

The transmissions are from Graves in France:

https://en.m.wikipedia.org/wiki/GRAVES_(system

For some demented reason, in my previous posts I started talking about very low frequency transmission, which is what I use for sudden ionospheric disturbance monitoring (SIDs). A recent result from that experiment (nothing to do with meteor pings) can be found here:

https://www.astronomy.me.uk/lichfield-radio-observatory-ukraa-sudden-ionospheric-data-sids-at-23-4khz-for-30-august-2025-compared-to-data-from-sid-monitoring-station-https-sidstation-loudet-org-data-en-xhtml

I hope it do not get confused like this during my talk/workshop/demonstration at EUCARA at the end of the week!

Thought for the week by the Bard of Lichfield:

Madness, madness, oh hail to the madness of the king!

He thought he knew, but behind was the queue,

Of those whose ideas were in a stew.

Andy

Sent from Outlook for Android

---

From: Andrew Thornett <andrew....@googlemail.com>
Sent: Sunday, August 31, 2025 10:44:28 AM
To: sara...@googlegroups.com <sara...@googlegroups.com>
Subject: Re: [SARA] Re: Listening to pings from meteors

 

[andrew....@googlemail.com]

I have just realised I have been getting some stuff mixed up and talking a load of rubbish.....I am going demented my excuse is not feeling well this week....

 

So starting again:

 

The meteor pings are at 143.048MHz (NOT VLF sorry!). They are detected using a FunCube Pro SDR Dongle and Moxon aerial on my log cabin at about 3m height off ground and pointed SW towards Graves.

 

The transmissions are from Graves in France:

 

https://en.m.wikipedia.org/wiki/GRAVES_(system

 

For some demented reason, in my previous posts I started talking about very low frequency transmission, which is what I use for sudden ionospheric disturbance monitoring (SIDs). 

 

 

 

Sent from Outlook for Android

---

From: Andrew Thornett <andrew....@googlemail.com>

Sent: Sunday, August 31, 2025 10:44:28 AM
To: sara...@googlegroups.com <sara...@googlegroups.com>

[Neil Smith]

The signal from GRAVES on carrier frequency 143.050 is intermittent, I think because of beam direction switching, so it misses a fair percentage of short pings. However, it's very useful as a meteor reflection demonstrator, because it illuminates a lot of sky and is loud. It's also great for looking at Moon doppler reflections and big targets like the International Space Station.

https://www.g4dbn.uk/?p=676

To get maximum benefit you need rather more than the usual 3 kHz bandwidth in a receiver as the ISS doppler can be up to about +-7kHz on some passes.

The relatively large ERP of the GRAVES system makes it much easier to look for Moon echoes than for transmissions from ham stations, although even that's fairly easy if you're in a radio-quiet location and have a decent antenna system that can follow the moon, or take advantage of horizon gain in the first few elevation lobes of a small yagi like my 9 ele.

You do need to steer the antenna pretty fast to follow the ISS on oblique passes though

I guess folks in North America might be able to see GRAVES echoes off the moon at low declinations with a common moon window, anyone tried that? Calculating the doppler shift is easy if you use wsjt-x to control your radio's tune frequency. 

Using GRAVES, if you beam east from the UK, you should see random meteor reflections during the typical early morning peak. I've had many contacts with stations all over Europe via meteor reflections on 144 and 70 MHz.

Neil

https://youtube.com/MachiningandMicrowaves