in general funneled input from the six original studios and any number of temporary
remote ("NEMO") points into eight outgoing channels. Two of the outgoing
channels were reserved for NBC's Red and Blue networks. Two more channels fed
the transmitters of NBC's owned-and-operated stations in Chicago, WMAQ (which
typically carried Red network programing) and WENR (which generally carried the
offerings of the Blue network). The remaining channels were assigned to special,
temporary networks ("jobs", in the NBC parlance) set up for specific
occasions, and to NBC's secondary outlets in Chicago (KYW, owned by Westinghouse;
WCFL, owned by the Chicago Federation of Labor; and WLS, owned by Prairie Farmer
Magazine) which carried some NBC programing when the facilities of WMAQ and WENR
were otherwise occupied.
Given the fact that NBC had two networks to service, it was often the case that
two or more of the Merchandise Mart studios were simultaneously feeding programs.
Master control could thus become a busy room indeed. To learn how one control
operator could simultaneously switch two networks and two local stations, click
Before you leave this location, take note of the large empty rectangular on the
wall above on the left. Not long after this photograph was taken, a cartographer
from the Rand McNally Company was brought to master control to execute a commission.
For a number of days, and with the aid of a ladder and scaffolding, he first covered
this space with canvas and then painted a large map of the United States upon
it. He indicated all the cities where NBC owned stations or had affiliates. In
one corner he painted the old NBC logo (identical to the one you've seen elsewhere
on these pages) and a representation of an RCA model 4A microphone. Then, wherever
there was a station that carried NBC broadcasts, a hole was drilled and a small
colored electric light was installed: a red light for a station that carried the
Red network, a blue light for a station that carried the Blue network, and an
orange light for a station that belonged to NBC's Pacific Coast network. What
resulted was a grandiose visual representation of the NBC networks.
The NBC network mural as it appeared in September, 1989.
Over the years this
mural was modified to reflect changes in NBC's structure. After the Blue network
was sold to the entity that became ABC, the blue lights were removed. The holes
were filled and painted over. The Pacific Coast lights were changed from orange
to red. The representation of the model 4A microphone was replaced with with a
representation of a "modern" model 44A.
Notwithstanding this room's transformation into "Video Central"(and
notwithstanding NBC's eventual departure from the radio business), the map remained
in place until NBC left the Merchandise Mart. Its lights generally remained burning.
Engineers, some of them perhaps religiously, replaced those that had burned out.
In a way, the map was like a crucifix above an altar.
My son was especially fascinated by the map. He began coming to work with me on
occasion from his second year onward. By the time we learned we were moving to
a new facility he was in his teens. "What's going to happen to the map?"
he asked me. I didn't know. Nor did anybody else.
A group of preservationists formed among the NBC staffers. Eventually the company
announced it would try to save the map. At some point after we moved to the new
NBC tower, but before our lease at the Mart expired, the canvas was removed from
its mounting, rolled up and put in storage.
In the fall of 1995, NBC announced that it would give the map to Chicago's Museum
of Broadcast Communications. Hopefully the Museum will find a place to properly