#Datatrak hashtag - Bluesky

1 week ago

2001 Google Earth imagery showing a Datatrak navigation transmitter in Filey. There are nine outer concrete pads in a radius around the mast, which are possibly guy wires. A further two inner pads are near the central concrete pad. Near the centre of the radius is a large concrete pad housing a transmitter hut and a lattice antenna tower.

The same antenna tower a bit later on.

In 2011 the antenna tower has been completely scrubbed from the landscape.

Oh damn, there WAS a #Datatrak TX station in Filey. Looks like it stuck around until between 2011 and 2018. By July 2018 it had been completely scrubbed from the landscape and replaced with a wind farm.

I can't overstate how rare it is for one to be completely […]

[Original post on digipres.club]

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2 weeks ago

Fun fact: the ethereal #Datatrak sound even got into a short film. "145 kHz" by Ian Bell and Julia Childs at Another Wave AV Productions.

https://www.youtube.com/watch?v=krF8f1Ic690

collections-search.bfi.org.uk/web/Details/ChoiceFilmWo...

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2 weeks ago

I think the thing I'm most chuffed about with all the #Datatrak stuff isn't the reverse engineering. It's that I added "wav file output" as an option and one of the people who helped build the system now has it as his phone ringtone.

I'm not far off doing that myself... after some filtering it […]

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2 weeks ago

Dilution of precision plot for four Datatrak transmitters covering Eastnor deer park. Quite why you'd spend hundreds of pounds and hours of effort exposing a couple of deer to less than a Watt of LF radio energy, I don't know... *cough*

I won't say why I'm using Eastnor Deer Park as a test location, but also please don't tell Jonty. #datatrak

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2 weeks ago

Field strength plot for the old UK Datatrak network

Weighted Horizontal Dilution of Precision (WHDOP) plot for the old UK Datatrak network

Repeatable Accuracy plot for the old UK Datatrak network

Confidence factor plot for the old UK Datatrak network

This is what the old Datatrak UK network looks like in field strength, WHDOP, repeatable accuracy and measurement confidence factor.
These seem to match up pretty closely with Williams (2004).
If you want to play with it, it's on Github […]

[Original post on digipres.club]

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2 weeks ago

If anyone else is interested in the #Datatrak LF navigation network, it turns out Alwyn Williams' PhD thesis is on the University of Bangor's website for download:
research.bangor.ac.uk/en/studentTheses/predict...

This contains a […]

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2 weeks ago

macOS and Linux autobuilds 95% pass rate. Takes under a minute (each) to run.
Windows autobuild? 45%. Takes 20 minutes to run.

I'm on the verge of disabling the Windows autobuild and saying "screw that platform".

(this is related to my trying to put together a #Datatrak network simulator and […]

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2 weeks ago

Doing work while I occasionally watch my poor Thinkpad running number crunching to undo the effect of an IIR filter by brute force and ignorance.
#datatrak things.

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2 weeks ago

Anyone wanting to make a hokey #Datatrak transmitter in the 1980s/90s would have had a job on. The phase values go through an IIR filter on their way to the trigger (sync marker) template matcher.
If you use the trigger templates from the firmware, it only matches on '1' bits. If you use a sine […]

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2 weeks ago

great, now I have an #EMFcamp project crisis: do I do the cable TV, or do I try and talk some people into putting up big masts and bringing back #Datatrak for one weekend only?

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2 weeks ago