Looking up a station?

General scanning discussion forum. Talk about anything to do with scanners, equipment, VHF/UHF reception and the art of catching those illusive signals!
Post Reply
User avatar
Dom
Regular
Regular
Posts: 33
Joined: 05 Feb 2010, 16:47
Location: North Wales

Looking up a station?

Post by Dom » 03 May 2010, 23:02

Ok I've got a problem. I've found this station and I have no idea what it is, I've no idea where it's coming from and I've no idea what it's for.

To give some detail it's longwave USB.

Where could I find the info on it, please?

island_state
Regular
Regular
Posts: 66
Joined: 10 Oct 2007, 13:41
Location: Scottish Borders

Re: Looking up a station?

Post by island_state » 04 May 2010, 00:55

A good start would be telling us the frequency! :D

Andrew
Banned
Banned
Posts: 2066
Joined: 07 May 2004, 09:07
Location: 55.36'N 4.39'W (I075 OR/UO)
Contact:

Re: Looking up a station?

Post by Andrew » 04 May 2010, 07:39

In some cases even tapping the frequency and mode into Google etc could help too, not always, but give it a go.
Banned Account

User avatar
Dom
Regular
Regular
Posts: 33
Joined: 05 Feb 2010, 16:47
Location: North Wales

Re: Looking up a station?

Post by Dom » 04 May 2010, 08:56

I've tried google, I've looked it up in the 'scanner directory'. I was reluctant to stick up the frequency because I wanted to find out what it is myself.

145.0 kHz USB. It's a repetitive 1970's space beep. and is still going now as I'm typing this.

StoatTB

Re: Looking up a station?

Post by StoatTB » 04 May 2010, 10:37

I originally thought it was a non-directional beacon (NDB) used by aircraft for navigation purposes, but that's higher up the LW band. I can hear one for Glasgow Airport on 331kHz with the CW ident of GLW.

On the frequency that you've given (145kHz USB), it's totally different and sounds like a pulse followed by an echo.

http://www.mediafire.com/file/mddzjjhm2g1/DW_A0030.wav The one you reported...

http://www.mediafire.com/file/zzmzerzdt ... 0031_1.wav Glasgow Airport NDB for comparison...

Apologies for the poor sound quality as it was done on a digital voice recorder in a hurry.

7hz
Regular
Regular
Posts: 79
Joined: 15 Feb 2010, 23:13

Re: Looking up a station?

Post by 7hz » 04 May 2010, 11:25

I am getting this signal quite clearly:

http://www.mediafire.com/file/wmj2zxgmw ... z_beep.mp3

Someone did a 'video art' piece about it in '96 - http://ftvdb.bfi.org.uk/sift/title/831052

Haven't found any more info yet.

StoatTB

Re: Looking up a station?

Post by StoatTB » 04 May 2010, 11:43

I think the mystery maybe solved...
Datatrak
Datatrak is a medium-area LF automatic vehicle location (AVL) system operating in the UK, Benelux countries, Germany and Austria. It is operated by Securicor Information Systems in the UK and by Siemens-Datatrak in mainland Europe. It was originally developed to fulfil a need for the monitoring of Securicor's own parcel and security vehicles, however it is now marketed to a number of other customers. The system is a conventional hyperbolic positioning system where a number of stations making up a chain transmit in sequence on a common pair of frequencies in the band 130 to 170 kHz. The receiver calculates it's position and communicates this back to the control centre (Swindon in the UK) by means of a UHF radio system that provides similar coverage to the LF network. The system is enhanced by the provision of Event Activated Tracking (EAT) or 'Trak Bak' as Securicor call the product. This allows a stolen vehicle to be tracked and aprehended. Also, the UHF component may monitor various inputs from the vehicle, providing a telemetry function.

There are apparently 14 sites in the UK but their location is unknown. The sequential transmissions are clearly audible at around 145 kHz in the UK, the interesting thing about them is that they 'warble' as if FSK modulated at around 20bps. Using Manchester coding, the transmission would still be usable for positioning as long as the phase were averaged over many symbols.

7hz
Regular
Regular
Posts: 79
Joined: 15 Feb 2010, 23:13

Re: Looking up a station?

Post by 7hz » 04 May 2010, 11:46

Just found that as well :-)

http://alancordwell.co.uk/radionavigation/systems.html

Now, where are the transmitters?

Also, from what I understand, we'll be hearing different transmitters at differing timing depending on where we are, right?

StoatTB

Re: Looking up a station?

Post by StoatTB » 04 May 2010, 12:05

7hz wrote:Just found that as well :-)

http://alancordwell.co.uk/radionavigation/systems.html

Now, where are the transmitters?

Also, from what I understand, we'll be hearing different transmitters at differing timing depending on where we are, right?
I'm not sure if it would be like the NDB beacons, which are usually 'live' towers in as much as they radiate rather than carrying any antennas, they are the antenna. I've seen one near to where Yeti lives, a now abandoned NDB with heavy porcelain mast insulators at the bottom.

From my limited understanding, that's how they would work - a bit like a radar pulse I would guess... :? Timing and the return data from the UHF link would be the key factor, I think. I does appear to be a form of DF'ing.

User avatar
Dom
Regular
Regular
Posts: 33
Joined: 05 Feb 2010, 16:47
Location: North Wales

Re: Looking up a station?

Post by Dom » 04 May 2010, 12:26

Mmm most interesting. I've got a half decent sample I'm looking at with some quite nifty software and I can safely say, it's not an echo.

I'll stick up my sample, just as soon as I decide on which file site to use.

Post Reply

Who is online

Users browsing this forum: No registered users and 3 guests