Date   : Fri, 27 Nov 2009 00:26:37 +0000
From   : ats@... (Adam Sampson)
Subject: Teletext receiver revisited

"David Hunt" <dm.hunt@...> writes:

> IIRC there were some remote pumping stations and sluice systems
> connected via UHF to decode messages sent via the hidden VBI lines in
> Teletext.

There's also a slow data transmission that's phase-modulated onto the
Radio 4 longwave signal, used to remotely switch large electrical loads
on and off:

  http://www.energynetworks.org/rts/
  http://downloads.bbc.co.uk/rd/pubs/reports/1984-19.pdf

This includes a UTC time signal, so a Radio-4-synchronised clock would
be entirely possible (although using an off-the-shelf MSF, DCF77 or GPS
receiver would probably be easier).

-- 
Adam Sampson <ats@...      >                         <http://offog.org/>