Lisa Hancock <hancock4@bbs.cpcn.com> wrote:
> With satellites and competing companies that own their
> own fibre networks, does AT&T still carry broadcast
> transmissions today? If not, when did the transition
> start?
Anthony Bellanga <anthonybellanga@withheld> responded:
> Also in the later 1970s, emerging national-in-scope Cable-TV
> services such as HBO, CSPAN, CBN, CNN, etc. chose to distribute via
> satellite directly to local cable franchise operation centers rather
> than use Bell System facilities. I also don't know if Bell had
> enough landline VIDEO capacity using the technology of the time for
> all of the new emerging cable services, on a NATIONAL basis.
The "new emerging cable services" didn't emerge until satellite
distribution made them economically feasible. Before satellites came
along, cable television systems relied almost exclusively on broadcast
stations for their programming.
Given enough money, the cable industry could have built a microwave
network with sufficient capacity to distribute non-broadcast
cable-only programming nationally. But the industry never considered
it: the cost would have been astronomical. By the early 70s, the
industry had been around for 25 years, and there were far more cable
headends (by some two orders of magnitude) than broadcast stations in
the country. A ground-based microwave network for cable TV would have
had to reach many more end-points than the network AT&T was operating
for the broadcast networks. Headends in remote places like
mountaintops or barrier islands might never have been reached.
The first nationally-distributed satellite-delivered non-broadcast
programming service was Time Inc's HBO, launched in December 1975 on
Satcom 3R. Prior to its satellite launch, Time had been using
non-AT&T microwave to distribute HBO to its own cable systems in the
northeast. Time wanted to extend HBO's coverage nationwide, and
satellite was the only economically-feasible way to do it.
Once HBO broke the ice, other non-broadcast services soon followed.
By 1979, programming was available from Turner Communications Group
(WTCG, now TBS Superstation), Christian Broadcasting Network (CBN),
Southern Satellite Systems (Satellite Programming Network, or SPN),
USA Network, C-SPAN (sharing transponder time with USA), ESPN, and
Nickelodeon. A year later, Turner launched CNN, the first in a string
of non-broadcast services that now includes Cartoon Network, CNNSI,
CNNFN, Headline News, TCM, and TNT.
Of course, not all of these new services survived. CBN became ABC
Family; SPN morphed into CNBC. Others flashed across the horizon and
disappeared: Reuters "Newsview"; TEC (The Entertainment Channel); HTN
(Home Theater Network); MSN (Modern Satellite Network); Cinemerica.
But the basic financial model worked: operating a non-broadcast
satellite-delivered programming service proved to be a viable
business. These services now make up the bulk of the programming
offered by cable television systems on their basic and extended-basic
tiers.
Lisa continued:
> With satellites, is there a problem with transmission lag
> time?
Anthony continued:
> Radio/TV network broadcasting is different [from telephone
> conversations] in that a program usually originates from one
> point (or maybe a small number of locations) and is sent to
> "everyone" across the country...
Programming production studios sometimes have a trio of video monitors
sitting side-by-side:
- The first displays the program signal directly from
the studio.
- The second displays the downlink from the programmer's
own uplink, after a delay of about 0.24 seconds (one
round trip to/from a geostationary satellite).
- The third displays the downlink from the DirecTV or
Dish Network, after a delay of about 0.48 seconds (two
round trips).
It's fascinating to watch the same image signal jump from monitor to
monitor. But a home viewer would never be aware of it.
But two-way phone conversations make the round-trip delay obvious. I
often notice this on CNN when the studio anchor asks a question of a
field reporter who is using a videophone. After the anchor finishes
the question, we watch the reporter just standing there (trying not to
look too stupid) for a half second before answering.
Neal McLain
[TELECOM Digest Editor's Note: I've noticed the television set in
my parlor runs about two seconds later than the televison set in
my bedroom. That is to say, the bedroom set displays an image and
audio, then the same audio/video appears a couple seconds later on
the other set. I wondered about that, then I remembered that the
television in the parlor is fed from the cable through the DVR; the
television in the bedroom is cable through converter box straight
to the television. It must be because the DVR first puts the signal
onto the hard drive (which is where it gets to to feed the television
set. PAT]
Neal McLain (nmclain@annsgarden.com)