Perseid Meteor Radio...?

[Woodsey65]

Hi there,

I need some help.

On 11/12th August we are holding a Perseid Watch at Buster Ancient Farm, Chalton, Hants PO8 0BG, starting at 9pm. Plug over. Oh, it's free for members...

Here's the science bit. What we'd like to do to add a bit more 'atmos' is to have the sounds of the meteors as they burn up, as they must give off some kind of radio interference as they rip through our atmosphere.

Seeing them would also be nice (!), but this has been suggested by one of our members and we love a challenge!

Any idea how to do it, what do I need? I guess this should be simple....

It's a big site and I'd think they'd be up for a large array to capture any frequencies given off. I have an amp, mixer and pole, antenna cables.

What kind of receiver of gizmo would we need?

It can be done, can't it?

Regards,

David Woods

www.hantsastro.org

[Greg]

Dave,

You've got me thinking...

I've had a quick flip around google and found some interesting stuff..

Which Frequency is Best? A commercial communications industry has been built around meteor scatter communications. The most common region of the radio spectrum for commercial two-way meteor scatter operation is from 30 to 50 MHz. This region of the radio spectrum offers the best of many factors related to meteor scatter communications. The frequency is low enough that the ionized trails from meteors efficiently reflect (actually the ionized trails refract radio waves, but that's another story) signals, antenna sizes are manageable, good stable receivers and transmitters are readily available, F layer ionospheric propagation is relatively rare, D layer ionospheric absorption is low, and this frequency range is not widely used for terrestrial point to point communications, most of which have moved to high VHF and UHF frequencies. More information on the history and utilization of meteor burst communication is at:

http://www.k5kj.net/meteor.htm#Frequency

How to make one.

http://members.bellatlantic.net/~vze2n9fe/meteor/details.htm

Greg

[timetraveller]

hi Dave do you know anybody who is a registered Amateur Radio Operator in or around your local area if they hold their ( A ) licence they should have the equipment you'll need for meteor scatter and if your lucky they might even own the kit for moon bounce transmission which entails tracking antenna arrays etc Regards Pete

[Woodsey65]

Brilliant, Thanks for that! One of our members is also a HAM operator in Tarbert, Scotland, so I phoned him and there is a local radio club about a mile from here so will contact them as you suggest. I'll see if they want to come along....

I'm also going to attempt to video the event, but I guess I need some sort of image-intensifier as well. Hope it's not cloudy! Should be a great gathering.

It's also our first for HantsAstro! Radio/Video/Audio - No pressure!!!!!?

I'll keep you posted.

Thanks again,

Dave.

[ringz]

Dave,

How's about this site.

http://www.tvcomm.co.uk/radio/

This is the guy who was on The Sky At Night last year.

--

Martyn

[Woodsey65]

Thanks Martyn,

I have fired off an e-mail and await a response.

Just had a chat with a local HAM operator and is looking into it and will get back to me.

Seems few do Radio Astronomy... is there anybody other there....?

Dave

[timetraveller]

glad to be of help dave I am alo a Radio Ham got my licience back in the seventies are you aware that amateur radio operators have their own satalites built by amateurs and launched for them by NASA the Satelites have the designation of oscar 9/10 they are soley for amateur radio use for world wide comunication if any of your local amateure radio club members are members of the group they may be able to give your hants club an interesting lecture dont be fooled by the amateur status, either some of the leading electronics and radio communication experts in the world are radio hams we even have expert solar scientist amongst our ranks as radio communication is very dependant upon ionisation of the layers in the upper atmosphere

regards Pete

[Baskii]

Hi Woodsey,

We're also having a Perseid evening at the Wycombe AS, and I had the same idea that you did. I've been looking into it over the last couple of weeks and have gone as far as to hook a large aerial up to my hi-fi tuner and listen out for some distant FM stations (although with no success).

Like you I've done some research on Google and the basics seemed to be:

(1) Draw an imaginary line between you and the radiant of the meteor shower.

(2) Draw a line at right angles to this and find a city about 1000km away from you along this line (in either direction).

(3) Find a powerful VHF transmitter (output around 100kW) in the region of the city, on a frequency not occupied by a local transmitter.

(4) Get a receiver that can pick up this frequency, connect it to an antenna and point the antenna at the sky. You should hear static.

(5) When a meteor passes between you and the distant transmitter, you should get a burst of the distant VHF station.

Well, that sounds simple enough, I thought...

The Perseid radiant is roughly NE, so I used the "Ruler" function in Google Earth to draw a line 1000km in a SE direction from my location, and found Milan.

Using the web site http://fmscan.org/ I searched for a VHF station with a power of 100kW in the Milan area and came up with one on 93.1MHz.

I tuned my radio to 93.1, where there isn't a local station, pointed my antenna in a roughly SE direction and slightly skywards, and waited...

...and waited...

etc.

Looking into it further, it seems that the lower end of the VHF spectrum is better, in particular the ~50MHz VHF TV transmissions still found in parts of Europe. However you need a receiver capable of picking these up, typically a "scanner" (there are plenty of them on eBay). Also a dedicated VHF aerial, such as a 3 element Yagi is best.

Well - that about taps out what I've found on the subject so far. If anyone can correct any howling errors I've made here I'd be grateful!

[Woodsey65]

Hi Martyn,

Got a reply from Andy Smith and is really bang on for detail....

"Hi David,

You're in a good position to receive pings from the French Graves satellite radar on 143.050 MHz, likewise you should receive good pings on 55.250 MHz from Portugal and Beligium. Last year at Selsea I thought Graves was the most dramatic with Doppler shifts of several kHz being heard.

Equipment-wise, for Graves, a minimum antenna would be a Discone or amateur 2m yagi of 4 or more elements pointed towards eastern France, and angled up about 8-10 degrees, and a USB capable scanner or amateur rig that can be tuned to 143.0492 MHz. For 55.250 MHz a 6m yagi pointed south-west, angled up 20-30 degrees, and a similar scanner or rig tuned to 55.2492 MHz USB. No pre-amps are necessary, especially for Graves.

I hope this is of use,

Regards,

Andy Smith."

Then I got in touch with a local radio astronomer, who has offer to loan me the equipment to do this.

SGL at work. I'll let you know how it pans out.

Thanks to everyone who responded.

Dave

[steppenwolf]

Looking into it further, it seems that the lower end of the VHF spectrum is better, in particular the ~50MHz VHF TV transmissions still found in parts of Europe.

I can confirm that between 30Mhz and 50Mhz would be a better place to search (another 'radio ham' )

[Baskii]

Thanks Steppenwolf. I'm watching a couple of eBay auctions at the moment - hopefully I'll be able to pick up a suitable scanner for about £40.

Woodsey, I don't know if you've seen it already but Andy Smith's web site is fascinating - it has continuous readouts of radio reflections on the frequencies he mentioned. You can also embed a web page on your desktop showing the current meteor activity!

Good luck with the Perseids. If I have any success I'll let you know.

[Woodsey65]

Baskii, I'm doing the same, but will most like leave any bidding until after our gig. Can't have us both raising the bids!

His site is cool, the smaller blips are aircraft apparently...

I'll post on how we go.

Thanks again to everyone

Dave

[Woodsey65]

Got a Realistic Pro 2035 1000ch 25-1300Mhz scanner a few days ago (eBay) and fitted it with a MRW-100 super gainer antenna. Works and tests well, as I'm getting FM signals from over 60 miles away. Will be adding Sky-Pipe software to my laptop so I can record and display the radio signatures. Now after a 2m Yagi I guess so it's more targeted... any other ideas???

Am I turning into a Radio Astronomer...? :shock:

[starf]

david entwhistle et al were more than helpful when i tried using an icom ic-r5. unfortunately i got nowhere with this receiver/scanner as does not have a usm mode. don't forget that all the transmitters are switching over to digitial so your foray into analogue may be short lived.

[Woodsey65]

david entwhistle et al were more than helpful when i tried using an icom ic-r5. unfortunately i got nowhere with this receiver/scanner as does not have a usm mode. don't forget that all the transmitters are switching over to digitial so your foray into analogue may be short lived.

Is the Cosmos digital....? My plan is more than just meteor catching.

RA looks quite interesting :scratch:

[Baskii]

Well I gave it a go but had no joy at all. To be honest, I was using a receiver without USB so that was a serious drawback, but I had a decent 2m Yagi. I've decided to concentrate on the optical side of astronomy for now - radio is too much of a distraction and I'm not willing to invest the time and money at the moment!

Woodsey, keep us posted on how your foray into the long wavelength universe goes!