[time-nuts] TV Signals as a frequency reference

[paul swed]

Hello to the group.
Been staying clear of the thread as many good comments.
Several things happened that made the color burst signal useless for most
people.
Yes the networks had Cesium's about 3 of them at CBS and the network feed
carried that quality.
but about 1980 a device called a frame synchronizer became popular. $25,000
each. This essentially locked the video to the local house reference.
Generally a free running ovenized crystal. At that point what was sent over
the air had no relationship to the network reference. The benefit of this
device is it allowed glitch-less switching between network and local feeds.
(Staying clear of a gen-lock discussion and terrestrial network microwave
links.)
It was the CBS network color burst that I tinkered with in 1990 to
ultimately see the satellite doppler shift on the CBS signal and other
effects.
Bad news it sort started me on the time-nuttery path and drugs like HP 5360
counters interfaced to computers.
Today the modern mpeg/atsc has none of these qualities and really doesn't
need it. Frame buffers exist in every TV. (Amazing) Originally I thought
ATSC might have value.
Regards
Paul
WB8TSL

On Fri, Mar 30, 2018 at 8:52 PM, Bob kb8tq <kb8tq at n1k.org> wrote:

> Hi
>
>
> > On Mar 30, 2018, at 6:13 PM, Hal Murray <hmurray at megapathdsl.net> wrote:
> >
> >
> > fgrosz at otiengineering.com said:
> >>  Now that analog TV has gone away, so
> >>  have these signals.
> >
> > What do the local TV stations use for a frequency reference?
>
> Anything from a crystal oscillator to a Cs standard. It’s very much a
> “that depends”
> sort of thing. If Crazy Bob is the chief engineer it might be a hydrogen
> maser ….
>
> >
> > Are there low cost receivers that also produce a good reference
> frequency?
>
> As noted earlier, color burst references were a big deal a long time ago.
> Depending
> on how they do what they do it might still be a good bet. The big risk is
> that it could
> be a good bet “most of the time”.
>
> Bob
>
>
> >
> >
> > --
> > These are my opinions.  I hate spam.
> >
> >
> >
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