NBC was televising shows from a few of their radio studios before they were converted to TV studios.

This photo was taken in Studio 6A on October 5, 1949 during a radio-TV simulcast of ‘Break The Bank’. There were four in house “mobile units”…the red, green, blue and yellow units, and each had three TK30s and a set of portable scoop lights.

The reason “mobile units” is in parentheses is because these were hybrid units that didn’t use a truck. Instead, the cameras were cabled to an existing TV control room there in 30 Rock.

At the time this photo was taken, only 3H, 8G and 6B had been converted from radio to television, and by that I mean those studios had their own control rooms, a new staging area with the floor seats removed and overhead light grids. But, 6A, 8H, 3A and 3B did have TV camera cable connectors and were used as television studios with the images routed to other existing control rooms.

With these four in house units, shows could be done from all over the building and remember, many of them were only 15 minutes, so that meant a lot of locations were necessary to go from one to the next. With a rehearsal, some of the units could move between studios and be ready to go on another show in about an hour.

At times, these units were actually in service with a truck doing broadcasts from some of the many NBC theater locations before they were converted to television studios.

Below, NBC veteran Frank Vierling looks back on the transformation of NBC Studio 3A from radio to television.