Re: Sun TV - Anecdote

["Dr. P. Sriram" <sriram@xxxxxxxxxxxxxxxxxx>]

On Tue, 9 May 2000, BGanesh wrote:

> Hi Dr. Sriram,
> 
>    Thx for the excellent how-to on clock sync.

good to note that it is appreciated. when i get going, it is compulsive
for me and i cant stop. if it helps someone understand something, then i
dont feel too bad.

> 
> Oh, this story goes a little bit back in time(1997?), when they were
> using VSNL to transmit to Singapore and downlink from there. You
                                          ^^^^^^^^
ahh, slip of the finger; you mean uplink

> would lose a little over second there. (speed of light calcs anyone?
> The satellite is ~35kms above the planet. Throw in equipment startup
                   ^^^^^^

ahh, one more slip of the finger; it's 35000 km. the round trip time is
usually well under 500 milliseconds, but since this is a constant, it can
be taken care of.

> One question : how many times have you checked the news clock against
> time1.iitm.ac.in ?
the first time i noticed it, it blew my mind; so, i have been checking
randomly about once a week for the last 3 months or so.

sriram

ps: more trivia. as of a couple of months ago, sun tv (and family) were
still using vsnl for uplink. they have several multi-megabit links from
their studios (near teynampet intersection) to vsnl. sun, surya, udaya etc
all feed through these links to vsnl and then up to the satellite. smaller
players like vijay still have small rooms at the vsnl facility where there
is a guy with lots of video players and tapes and a wall clock (!). the
video signal then is fed to vsnl for uplinking. this vsnl facility on
beach road is one of the most fun places i have visited. so much
technology, mostly applied in everyday use. all the internet pipelines,
the international speech circuits, cable tv signals all come there. and
they are all mixed up in the right proportions and sent on to appropriate
destinations.


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