A few questions about the AT&T "Long Lines" Coaxial Network

[Stanislav]

Most of my limited technical knowledge of video-related matters is haphazard and has just been picked up here and there over the years. (I never took any electronics or engineering courses.) So, I pose a few questions regarding the old AT&T coaxial network for those more technically-savvy members to answer:

(1)How many video signals could be carried simultaneously on one coaxial circuit? And how were they separated (were there discrete assigned frequencies/channels for each network, each special event or ad hoc feed, etc.)?

(2)Could anyone linked to the system theoretically pick up any feed that happened to be passing through their neck of the woods? Or were the end-users only fed the specific feed(s) over their connection that they were "authorized" to use?

(3)Were there ever any notable conflicts between users over the availability of a circuit?

(4)Were there ever any system-wide or regional failures of the system that impacted network programming?

 

[oldiesfan6479]

(2)Could anyone linked to the system theoretically pick up any feed that happened to be
passing through their neck of the woods? Or were the end-users only fed the specific feed(s)
over their connection that they were "authorized" to use?

From past personal experience...

If AT&T had all three networks coming through their local TOC, the local loop
to each station would have only their affiliated network.

That said, if your net had signed off for the night and you knew the Telco guy
on duty, you could get him to switch your feed to one of the other nets for a
while overnight. (Just don't forget to get it switched back.) Anyone remember
the "ringdown" phone? Pick it up and it automatically rings the local AT&T shop.

If you carried programs from more than one network, it's possible (my speculation)
the same thing was coordinated on an official basis, where the local Telco switched
you from one net to another for a given time period, during the station breaks.
I tend to doubt that most dual affils had two independent sets of lines coming in.

Years ago, instead of just a test pattern ID or (later) bars and tone, CBS would
send the WCBS-TV New York local feed down the net during overnights, so you
could watch the Late Late Show inside your station in Peoria or wherever.

 

[rwells2265]

If you carried programs from more than one network, it's possible (my speculation)
the same thing was coordinated on an official basis, where the local Telco switched
you from one net to another for a given time period, during the station breaks.
I tend to doubt that most dual affils had two independent sets of lines coming in.

I wonder if maybe the larger ones (Birmingham comes quickly to mind) did have two lines? Especially for situations where a station would tape-delay given programs on the secondary network to air later. While a 16mm kine would suffice for a small-market station wanting to run "General Hospital" at 4:30 p.m., I'd think the bigger guns would prefer to spring for the second feed. Just my guess.

Besides, with Birmingham's net landscape 1965-70, I'll bet AT&T had a job classification called Engineer In Charge Of Birmingham.

--Russell

 

[bpatrick]

Did that engineer also have Raleigh/Durham? From
1968-71 the same thing went on there, with WTVD/11
getting first call on CBS and NBC, and WRDU (WRDC)/28
getting the leftovers.

Here's a hypothetical: it's January 1969, the station
is in the Eastern time zone, is CBS primary, ABC secondary,
and carries "As The World Turns" at 1:30 (ET). Could it get
the Pacific feed of "Let's Make A Deal" at 4:30 (ET) if it wanted
to carry it, or would it be forced to tape the Eastern
feed at 1:30?