The simple B-B-C jingle used between every 5 or so pieces of testcard music as a tuning signal.

BBC jingle

The BBC Home Service's news at 10pm on 14 August 1967 reports on the closedowns of the offshore stations as the Marine Offences Act comes into force.

BBC Home Service on the offshore radio closedowns

In 1941, the BBC began prefixing their transmissions to the European mainland with 'V' in morse code, a practice that was so successful they kept it up long after the end of the war. http://www.transdiffusion.org/2015/07/16/dot-dot-dot-dash

BBC 'V for Victory' tuning signal

BBC-1 on a Sunday afternoon in 1965 is repeating the imported US series "Arrest and Trial" when the sound disappears. Continuity put on a record and apologise.

BBC1 lost of sound during "Arrest and Trial" in 1965

We come out of The Sam Costa Show on BBC Radio 2 in 1968 into the Greenwich Time Signal - but not the one we're used to these days.

The Sam Costa Show into the old-style Greenwich pips

The independent broadcasting authority since 1964

BBC1 lost of sound during "Arrest and Trial" in 1965

Transdiffusion