The 1940s Broadcasting House Control Room - page 2

To the far left of the front bench was a junior operator known as "SB". Standing for "Simultaneous Broadcast" this sounded a very important job. Let me explain. At this time the Home Service was not a network but consisted of seven independent regional services, each with its own continuity. Much of the time, programmes came from London and were fed to Birmingham and on to the rest of the country but if a programme originated in Bristol, then the incoming line from Bristol had to be fed to Birmingham, the London continuity feeding only the local transmitters. Similarly, if Birmingham was the source then the feed to Birmingham had to be broken away to prevent a possible howl round. There was a 10 second switching pause between programmes in which to carry out this simple task which was given to a junior on the basis that they wouldn't dare miss a switch and also because they were available most of the time to do tea rounds. Quite a demanding job in itself as tea rounds were large and very heavy in the days of china cups and saucers. Behind the front bench were more bays, overflowing with amplifiers, power supplies, line equalisers, test gear and so on. Also lurking near the back of the control room, but not shown in the pictures, were six autochanger 78 RPM grams used for playing out line idents.

Line amplifiers
AC test bay

Above left: Some of the incoming and outgoing line amplifiers. Near the centre of the picture is the AC Test Bay, seen in detail on the right.

Distribution amplifiers
Left: Distribution amplifiers ('Trap Valves') with their power supplies below them. This type of amplifier was succeeded by C/9s.

Below left are the equaliser trays of the Greenwich Time Signal lines. The 'pips' actually came from Herstmonceux in Sussex. The signal sent was a continuous tone with 6 gaps every 15 mins. This was 'inverted' into 6 pips at BH. This arrangement made it easier to detect a line failure. Below right: GPA/4A amps looking a little out of place among the much older gear seen in other pictures.

Equaliser Trays
GPA4 Amplifiers

Relays and Trap Valves
Check receivers

Left: relays and more trap valves. Right: check receivers with the control room Tannoy intercom amp at the top of the bay.