Listening to Meteors on your FM dial.

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PaulB
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Listening to Meteors on your FM dial.

Post by PaulB »

In the December 1997 issue of Sky and Telescope, there is an interesting article on "Radio Meteors on your FM dial"

I am curious to know whether or not this works, and wondered if any body on here has ever tried it?

I'd like to have ago, because usually the weather doesn't play ball; and I used to be very active in the field of visual meteor observing.

I have all the equipment. A analogue tuner with a FM antenna attached to the roof of my house.

If you have any tips or have done this. Please contact me.
Paul Anthony Brierley
Observation Co-ordinator for.
Macclesfield Astronomical Society
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M54
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Post by M54 »

Read something along these lines about 3-4 months back, just not a clue where. Will search around.

Other question: What were you doing reading a 1997 edition of Sky and Telescope? :lol: :lol: :lol: :lol:
Davej
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Post by Davej »

Hi Paul,
Thought about this before but never tried it.
I should have done realy as I have got the right equipment and ext. ant.
this might be helpful for starters.
ATB
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LeoLion
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Post by LeoLion »

Hi Guys , Have you checked out under SPA 'Meteor' in the 'Header' above and worked through what is available on radio meteors . David Entwistle is an SPA officer of that section is a very active radio meteor man . If you watch Sky at Night on the Beeb you may well have seen him in Patrick M's garden in Selsey with his antenna and laptop . There has recently been an addition with more info on radio meteors on the SPA site and I feel quite sure David would be helpful with any enquiries. He posts quite often on 'matters meteoric' here.
Hope this helps :D

Len E
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Re: Listening to Meteors on your FM dial.

Post by david entwistle »

PaulB wrote:In the December 1997 issue of Sky and Telescope, there is an interesting article on "Radio Meteors on your FM dial"

I am curious to know whether or not this works, and wondered if any body on here has ever tried it?

I'd like to have ago, because usually the weather doesn't play ball; and I used to be very active in the field of visual meteor observing.

I have all the equipment. A analogue tuner with a FM antenna attached to the roof of my house.

If you have any tips or have done this. Please contact me.
Dear Paul,

Yes, in principle you can listen to meteor echoes using a broadcast receiver on the FM band. The complicating factor is that the VHF Band II spectrum (FM Band) is pretty congested and the bandwidth of the domestic receiver is very wide. This makes it difficult, but not impossible, to find a suitable bit of spectrum. It'll be a lot easier in remote locations and more difficult in densely populated regions. So, it'll be a lot easier from the north of Scotland, or north-west Ireland, than from the midlands say. You'd probably struggle to find a suitable frequency if you are in a major conurbation.

What you are looking for is a frequency with no local transmitters, but a strong distant transmitter. The first criteria is the difficult one, if you can find a quiet local channel, then the chances are that there will be something on it somewhere in Europe, or beyond. To reduce interference from adjacent channels, switch the receiver to mono, if you can.

If you find a suitable quiet channel, and you un-mute the receiver, you'll just hear white noise (hiss). Then, assuming there is a strong distant station on that channel, a meteor reflection will generate a burst of programme material. You may even receive the RDS (station ident) data during a stronger reflection. It is a common misconception that you'll hear "pings". You'll not hear pings using a FM receiver to listen to an FM transmission. You only hear "pings" using a single sideband receiver to receive an unmodulated carrier.

The only thing to do is give it a go. I'd suggest trying 105.0 MHz for starters and see how you get on. There are a couple of low power stations locally, but there wasn't anything powerful the last time I looked - a couple of years ago.

One disadvantage of this method of radio meteor detection is that the detection is difficult to automate. Computers aren't good at distinguishing programme content from white noise. This is one reason that the majority of radio meteor observers use a scanner, or communications receiver, rather than a broadcast receiver. One solution is to modify the receiver to give you access to some indication of signal strength and use the computer to log this and automatically detect increases i signal strength. That's a more advanced subject though and may require agreement from the other half, before you pull the stereo to bits...

Excellent timing for the Leonids, by the way.

Good luck,
David Entwistle
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Re: Listening to Meteors on your FM dial.

Post by david entwistle »

david entwistle wrote:The only thing to do is give it a go. I'd suggest trying 105.0 MHz for starters and see how you get on. There are a couple of low power stations locally, but there wasn't anything powerful the last time I looked - a couple of years ago.
Here are a sample of meteor reflections recorded using an FM receiver, on 105.0 MHz, over the last day (2009/11/22-23). Note the hiss gives way to programme content and then returns. The audio is encoded as .wav files.

Sample 1 (114 KByte)
Sample 2 (81 KByte)
Sample 3 (82 KByte)
Sample 4 (79 KByte)
Sample 5 (83 KByte)

Although I used a scanner, it was set up to behave just like a domestic FM receiver - wide (230KHz) bandwidth, low sensitivity, FM demodulation. The aerial is a four element Yagi, at 2.5m above ground facing east, horizontal polarization.

I'm not sure what the station is, but I think it may be Radio Prague, from the Czech Republic, which transmits with 100KW effective radiated power, if I remember correctly.
David Entwistle
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