[mythtv-users] Electrical power in my cable line? Is that bad?

Jay R. Ashworth jra at baylink.com
Fri Sep 7 14:44:04 UTC 2007

On Fri, Sep 07, 2007 at 07:21:24AM -0600, Brian Wood wrote:
> The reason 60 cycle AC hum moves up the screen is that the NTSC frame
> rate is not really 60/sec, but 59.something (sub-multiple of 3.579545
> color subcarrier which, if it were 3.600000 would result in a precise 60
> Hz. frame rate).

59.97.  It used to be 60, back in the days when black and white
programming actually moved with no chroma subcarrier.

Fun fact: the 3.58 oscillator in a TV used to be the most accurate
frequency source a general consumer could get their hands on -- *when
the TV was tuned to a network color program*.  The local affils used to
pass through the actual subcarrier from the network.

Clearly, they don't anymore.  :-)

-- jra
Jay R. Ashworth                   Baylink                      jra at baylink.com
Designer                     The Things I Think                       RFC 2100
Ashworth & Associates     http://baylink.pitas.com                     '87 e24
St Petersburg FL USA      http://photo.imageinc.us             +1 727 647 1274

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