How to use Information Exchange

This page is intended to help people who are seeking or offering assistance with matters relating to BBC engineering. To contact the originator of an item below, create an email by clicking the relevant link. I will forward your email to the intended recipient. If you would like an entry on this page click here to create an email.

Bing Tone Generator

Keith Wicks writes: I'm looking for information on bing tone. I remember we used to use this slowly pulsating signal before startup of the main radio networks in the early 1960s. I think it was described as the least disturbing signal to have to listen to for long periods.

Does anyone know what the frequency and waveshape were, and are there any publications on the subject? I ask because I occasionally have the need for something similar and thought I'd build a generator. I'm hoping to find a circuit of a transistorised Bing Tone Generator, if such a thing was ever made, but a valve circuit would be of interest too.

Any help would be much appreciated.

"Digger" Dimmock

Gavin Dimmock writes: I found your web page and email while searching online for information about my late grand father, James William Dimmock.

He was employed by the BBC between July 1946 and May 1972 when he retired. I believe he worked in S.P.&.I.D. and, for a time at Bentinck House. I have very little information about his working life and am keen, if possible, to discover more.

I believe he was possibly a draughtsman. His nickname (I do not know why) was “Digger”.

If you are able to provide me with any suggestions of how to proceed, or where to go next, I would be so very grateful.

Alexandra Palace - colour date?

John Escolme, BBC History Manager, writes:
"I am trying to find out when Alexandra Palace was equipped for 625 line colour production.
Did they get it done in time for the Wimbledon colour launch 1
st July 1967, News and Sport from AP was at 1930 that day.
I suspect it was not ready, as only a select number of programmes went out that day in colour – officially, and all from, or via TVC.
Wimbledon, all week +Match of the Day
One Pair of Eyes, Sat July 1
The Virginian, Mon July 3
Impact, Thurs 6
th July
Late Night Line Up – all week   
This info comes from the RT at the time, so I don’t preclude colour coming from AP early, but it might be that AP was not ready for 625 line colour at all until News started in colour on BBC1 in 1969, which of course then was still coming from AP. I do realise there were colour tests from 1954, but that’s another matter.
Any ideas?

Disposal of Technical Instructions

In March 2016 I will dispose of Technical Instructions T4 and T6 (prints dated 1955 and 1949), unless you tell me that you would like them. UPDATE: Now held by Nick Cutmore.

Disposal of Eng Inf prints

In March 2016 I will dispose of the original Eng Inf prints that I scanned for this page, unless you tell me that you would like them. UPDATE: Now held by Nick Cutmore.

AM6/11, UN14/9, ADR F600-LB

Jonnie Wacker is looking for a schematic for an AM6/11 and analogue delay UN14/9. He also has an old BBC rack that contains an ADR F600-LB limiter and some PYE mic amplifiers (the type with half moon faders) and would like to get hold of the pinout/schematics for these units. "Thanks for the help much appreciated."

Technical Instructions

Nick Cutmore writes: "Before the BBC introduced the Apparatus in Code Order folders, technical information was held in "non unit code specific" TIs - each of which related to a particular specialisation such as "Recording" or "Sound". The information for each of these specialisations was published in a folder (or folders) in sections (the sections themselves were sometimes published individually as well in paper covers)." More….please click here.

Lister generator

Roy Craggs writes: "I have in my collection a Lister 9 kva genny, powered by an FR2, water-cooled engine. Believed to be from BBC Radio Scotland as part of the Cold War contingency planning for enabling radio stations to continue transmitting in times of national emergency, ie grid failure, due to bombing. Dating from the late 1950s, I have some service records and also the control cabinet which enables fine tuning of both voltage and frequency. I intend to show the rig at vintage shows and would welcome any info on these units deployed by the BBC, or any photos showing them installed. Unusually for Lister engines, they appear to have been supplied from the factory in black, rather than Lister green. Anyone out there remember them? All info gratefully received. Thanks"

Earlier Information Exchange requests

Please click here to see earlier Information Exchange requests.