[time-nuts] Using digital broadcast TV for timing?

Bob Camp lists at rtty.us
Wed Feb 8 17:21:02 UTC 2012


Hi

These days the easiest solution might be to put an Ethernet device a few
floors up (where you can see the sky) and haul packets on down to the bottom
of the canyon. 

Bob

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Chris Albertson
Sent: Tuesday, February 07, 2012 9:01 PM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Using digital broadcast TV for timing?

GPS requires a good view of the sky,  Hard to do in say the 7th floor
of a 40 story building if you have no windows.   I'm wondering about
using the new digital TV signals for timing.

I'm pretty sure there is time code in the signal and I'm pretty sure
the bits are clocked at a very accurate rate.   Also TV receivers are
very easy to find and put "hooks" into.      I'd bet the broadcast TV
signal could be almost as good as GPS.

The plan is to try and phase lock a local oscillator and use a very
long time constant on the loop filter.   I bet the TV transmitters are
locked to GPS and over a long enough time are as good as GPS.  Also in
many cities there are many TV transmitters, should be able to take
advantage of that.

 Before I try some experiments anyone want to tell me why I'm wrong?
-- 

Chris Albertson
Redondo Beach, California

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