Looking for "Datatrak" info / recordings of ~130-145kHz LF radio band - Page 1
Forum section: electronics / projects

author: philpem
author_rank: Frequent Contributor
timestamp: October 26, 2015, 12:47:01 am
content: Hi there,I've picked up an old (read: ancient) first-gen Datatrak receiver. For those not aware, this was an old geolocation system which operated on the LF radio band from the 1980s up until a couple of years ago. It functioned similarly to Decca Navigator, but on land instead of sea.Before I either try and make it run 68000 BASIC (or something) or gut it and reuse the case, I'd like to see if I can at least generate a signal it recognises as "valid enough to say something other than 'FAIL' on the serial port". To that end, does anyone have copies of the following?Any recordings of the Datatrak frequencies (133.477kHz, 146.705kHz UK, and quite a few others in the 130-150kHz range) made while they were still in operation. I've found a few Youtube videos but the audio is quite poor.T. Scorer (1990). Vehicle Location System. Paper presented at the International Conference on Navigation NAV90, The Royal Institute of Navigation, London, September 18-20, 1990. (I've seen this referenced, but it's not in any library catalogue I've checked this weekend -- here's the TOC:http://www.gbv.de/dms/tib-ub-hannover/019676190.pdf)A. G. Scorer (1991). The Development of Datatrak. Journal of Navigation, 44(1), pp 37-47. doi:10.1017/S0373463300009711. (Apparently covers an early version of Datatrak - this would be nice to have for the "how did it start" angle, and I suspect the later paper may reference it)Got thisTony Scorer and David Last (1995). The Current Status of the Securicor Datatrak System. Journal of Navigation, 48(2), pp 204-214. doi:10.1017/S0373463300012662. (if I could pick just one of these papers, this would be it)Got thisI was quoted £49 each for the latter two research papers by the British Library... if anyone knows a more wallet-friendly way to get hold of them, please let me know! I plan to ask the local library tomorrow on my way home from work...This is probably one of those "fool's errand" projects, but at the moment the thing is sat on my desk, I've managed to figure out what a few of the serial port commands do, and I've figured out the IF frequency (somewhere around 20kHz). I just haven't got it to do anything particularly useful...And frankly, I find the whole "what did we do before GPS?" angle to be rather interesting. The curse of the radio amateur I guess!Cheers,Phil.

author: AF6LJ
author_rank: Unknown
timestamp: October 26, 2015, 12:54:04 am
content: We did a lot of very cool things before GPS and will revert back to them when the next huge CME is thrown out way.There was your system which relied on a number of stations for radio location, there was LORAN A and C, OMEGA and good old fashion VOR. I miss OMEGA, I use to have a VLF receiver that could pick up the timing pulses. I'll bet with a couple of reference locked AFGs you could even create a test signal to find out if it works.What a Cool project.

author: philpem
author_rank: Frequent Contributor
timestamp: October 27, 2015, 12:26:36 am
content: Quote from: AF6LJ on October 26, 2015, 12:54:04 amMaybe! I stumbled across some papers on using LORAN as a fallback for GPS due to the latter's ease of jamming... So the old ways seem to have some merit.Quote from: AF6LJ on October 26, 2015, 12:54:04 amThank you!Well, I've got the Tony Scorer and Scorer and David Last papers, but they're not terribly useful - they're more a technical overview than any in-depth examination of the system. I've found a couple more, but they're all in the conference proceedings from the Royal Institute of Navigation and thus aren't held by any of my local libraries that I can tell...I've also got a list of alternative Datatrak frequencies for other countries:Code:131.70 kHzLocations unknown141.7647 kHzBelgium: Momignies Beauwelz (004E1020 50N0100), Ravels Poppel (005E0200 51N2700), Veurne Houtem (002E3720 51N0038)Luxembourg: Burmerange (006E1900 49N3000)Netherlands: Bocholtz (006E0100 50N4900), Drieborg (007E1300 53N1300), Nieuwe Tonge (004E0800 51N4300), Slootdorp (004E5500 52N5000), Winterswijk (006E4300 52N0200)131.80 kHzLocations unknown132.5000 kHzAustria: Amstetten (014E5032 48N0123), Bisamberg (016E2312 48N1837), Bregenz (009E4204 47N2655), Gmunden (013E4546 47N5538), Horn (015E3610 48N4350), Oberpullendorf (016E3311 47N2715), Passau (013E3536 48N3218), Zurndorf (017E0755 48N0041)132.80 kHzLocations unknown133.20 kHzLocations unknown133.24 kHzArgentina144.6000 kHzNetherlands: Bocholtz (006E0100 50N4900), Drieborg (007E1300 53N1300), Nieuwe Tonge (004E0800 51N4300), Slootdorp (004E5500 52N5000), Winterswijk (006E4300 52N0200)144.6305 kHzBelgium: Momignies Beauwelz (004E1020 50N0100), Ravels Poppel (005E0200 51N2700), Veurne Houtem (002E3720 51N0038)145.20 kHzLocations unknown145.50 kHzLocations unknown – see 145.5100kHz below145.5100 kHzAustria: Amstetten (014E5032 48N0123), Bisamberg (016E2312 48N1837), Bregenz (009E4204 47N2655), Gmunden (013E4546 47N5538), Horn (015E3610 48N4350), Oberpullendorf (016E3311 47N2715), Passau (013E3536 48N3218), Zurndorf (017E0755 48N0041)146.40 kHzArgentina and possibly South Africa146.50 kHzLocations unknownApparently the Argentina network was active as of June 2014, going by this:So if there's in anyone in that area of the world with a longwave receiver that goes down to ~130kHz reading...From what I can gather, the UK network is gone-ski. Nothing currently transmitting on the allocated frequencies -- or so I've been told. If anyone's got an LF / LW antenna and a receiver kicking around I'd love to be proven wrong!There was an eBay advert for one of the masts, which ended today:http://www.ebay.co.uk/itm/MAST-160-ft-GUYED-RADIO-MAST-IN-10ft-sections-EX-DATATRAK-/311466221228(alas, according to the seller, Datatrak had been in and stripped out the transmitter hut beforehand and left the mast behind).Still working on getting copies of the NAV90 paper, also looking for this one if anyone has it. A book references it and claims it includes actual technical data (!):Hartinger H, Willson MJ, Cousins N (2001): Augmentation of satellite positioning with an LF system. Paper presented at the International Conference on Navigation NAV01, The Royal Institute of Navigation, London, November 6-8, 2001.Cheers,Phil.

author: AF6LJ
author_rank: Unknown
timestamp: October 27, 2015, 12:52:44 am
content: There was another system you might be interested in; ARGO DME, a Cubic Corporation product.It was a "portable" DME system used by oil companies in the 70s through the late eighties.The signals in your video sound a lot like those. ARGO DME rain between 1700 and 2.1 MHZ (this is from memory)

author: electrovito
author_rank: Newbie
timestamp: July 11, 2016, 12:51:05 pm
content: Hi there.Stumbled across this tread via Google.I have the old installation manuals for the Datatrak units as I used to and do still fit the newer GPS version. This has the commands in when you are talking to it.I also have about 30 old LF/UHF and GPS/UHF units, old antennas and the programs we used to commission the vehicles with.Message me if you have any questions.Al

author: philpem
author_rank: Frequent Contributor
timestamp: July 23, 2016, 07:28:13 am
content: Quote from: electrovito on July 11, 2016, 12:51:05 pmThanks very much for your kind offer! I've sent you a PM.

author: M7NOG
author_rank: Newbie
timestamp: October 31, 2021, 10:10:54 pm
content: Hello!I realise it has been 5 years since this topic was active but was wondering if any of you guys managed to get documentation on these systems, and I tried to PM Al but his inbox is full (or it says it is to new members trying to PM people!) - to ask if you still have any of the LF gear?Derek

author: electrovito
author_rank: Newbie
timestamp: November 01, 2021, 09:03:02 am
content: Hi DerekI sent some manuals to Phil but confess I did not get round to sending the hardware. I still have some MK4's (LF/UHF) Mk5's (GPS/UHF) and a shed load of MK6's (GPS/GPRS) (As my work has just recently changed to our own inhouse tracking system.)I have recently been driving round the old LF stations across the country to see what state there in and if there are any useful bits and bobs in.I have got the book Hofmann-Wellenhof, Legat, Wieser. Navigation principles of positioning and guidance if anyone wants some screen shots?not sure why you could not PM me though.......Al

author: philpem
author_rank: Frequent Contributor
timestamp: November 01, 2021, 10:56:58 pm
content: Quote from: electrovito on November 01, 2021, 09:03:02 amI think I've still got those manual -- I don't think I ever got to look at the Mk4 hardware, I mostly have Mk2s. Although I did eventually pick up a Mk2 TrakBak with antenna, which means I now have the 8051 ROM (for the radio board).I've been slowly reverse engineering the Mk2 design -- I had a dead one I've desoldered and de-layered, then scanned the PCB layers. The RF stage is fully reverse-engineered at this point, with the CPUs still to do. The Mk2 ASIC is a bit of a black box.I've got a website page on my Mk2 reverse engineering project:https://www.philpem.me.uk/datatrak/startI've built a fairly simple Datatrak signal generator based on a DDS chip, but hit a bit of a snag in that the code (in the Mk2 ROM) which decodes the time-of-day ("clock") signal isn't terribly obvious.I've got recordings but haven't (yet) managed to demodulate them back to phase data.Quote from: electrovito on November 01, 2021, 09:03:02 amInteresting! Have you found anything?I did see a few things pop up on ebay - a rubidium frequency source and a roll of co-ax cable labelled as a "delay line". Sadly I haven't found anything else -- the navigation transmitters seemed to be long gone. I can't help but wonder if some enterprising ham got hold of them.From the people I talked to, the exciter was a VME-bus based thing with a 68000 processor and some custom hardware. That drove a MOSFET high-power longwave RF transmitter. The signal is phase-modulated so there's no data stored in the carrier amplitude -- so a Class E amp would be more than enough. I think they mentioned that the whole transmitter setup was called a "Nav Rack".Quote from: electrovito on November 01, 2021, 09:03:02 amI'm not sure I've seen that one -- is there anything good in it?CheersPhil.

author: CaptDon
author_rank: Super Contributor
timestamp: November 03, 2021, 02:57:52 am
content: I was an avid user of the 100khz Loran-C system and nearly cried when it was decommissioned. What a sad day when we lost the back-up to GPS!! I had some nice Raytheon ChartPlotter gear and a T.I. avionic unit which I used in a Class-A tractor trailer!! When I first got into S.W.L. the old Loran-A system was still active and very prominent on amateur 160 meter receivers!!! Fortunately, most of my Loran-C gear could also read Nema-0182 GPS data strings so the equipment didn't end up in land fills. E-Loran I guess has never been deployed?? Why did they rip down all the nearly new solid state Loran-C sites when E-Loran could have used the same towers and transmitters??? I guess they needed some way to make Nautel rich and waste taxpayer dollars???

author: electrovito
author_rank: Newbie
timestamp: November 03, 2021, 09:45:17 am
content: Hi Phil.You have been busy!Not a lot left in the old LF cabins as they did strip them out when the decommissioned them. (I am sure one of the old technicians said he has an LF transmitter in his garage! (pity he does not have 3!!)) Ill ping you a google images link of them now and how they were back in the day. (over you personal email.)Funnily enough they did leave the MK4 and the Mk5 units I fitted in the cabin that is open as you will see in the photos.The book is a general description of what it was and how it is similar to the other sea based navigation aids as previously discussed. I don't think it will tell you anything you don't already know!Al