Alan Taylor
Which was the first rigged OB?One site [on the web] claimed that it was the Cenotaph Armistice event of 1937
However, I can confirm that … the first OB was the Coronation procession of King George VI.
Talk about jumping in at the deep end – having a Coronation as your shakedown programme for the first ever OB van. Apparently the picture vanished as the King approached and a swift kick to one of the racks solved the problem just in time. It later turned out to be due to be down to a dry joint. It appears that during the Coronation, the MCR was primarily manned by Marconi-EMI engineers rather than BBC staff because so much of the equipment was new to the BBC. After the rush of the Coronation, the MCR was withdrawn from operational duties for 6 weeks so that staff could become proficient with its operation.
Archived copies of Radio Times didn’t always list TV programmes, but sometimes did, while “Wireless World” in those days published a lot of articles about television and every week (it was weekly pre 1939): it published a list of forthcoming TV broadcasts and always mentioned OBs. By July 12th they were scheduling experimental OBs from Wimbledon of the Davis cup. Between 15th August and 4th September the OB unit were relaying pictures from Regent’s Park Zoo, primarily for the Radio Olympia show, where the BBC had a large demonstration area. Then there were OBs covering Air Racing from Hatfield (with disastrous radio links – see below), football from Arsenal, King George V dock, and shows from various film studios, starting with Pinewood. There were many other OBs before Armistice day.
The Coronation used a special trunk cable installed around parts of central London, but other shows used 64MHz radio links. Reception of those radio links was initially done from the aerial tower at AP, but they encountered problems, especially in windy weather. It was believed to be due to an intermittent connection in the TV transmitter aerial or mast creating unintentional radiation, but the problem was never resolved despite many attempts. The interfering signals were well over 10mV, while the received signal was less than 2mV. The interference manifested itself as very heavy white splashes on the screen and disrupted the frame synchronising too..
They then tried receiving from the other tower at AP, which was no better and after various experiments concluded that nowhere within a mile of the AP transmitter was suitable either. Finally by spring of 1938 they decided that receiving OBs from a site adjacent to a massive transmitter was futile and their search for an alternative led them to Swain’s Lane on high ground near Highgate. Successful experiments were conducted from a nearby church spire and they initially used a temporary tower at Swain’s Lane to raise the reception aerials. Then they built a permanent wooden tower, which was eventually replaced with a metal one which I believe is still there ( judging by satellite photos ). I worked at Swain’s Lane on many occasions when on attachment to Radio Links.
Many people talk of the BBC’s war contribution via "Beam Bending", using the TV transmitter at AP to disrupt the Nazi bomber navigation system. The original beam bending countermeasures applied to an earlier German navigation system, X-Gerät and that beam bending was done by non-BBC means. The BBC were deployed to defeat the more sophisticated Y-Gerät system. The most technical accounts I have discovered seem to suggest that the beams weren’t bent as such, but by using Swains Lane in conjunction with the AP Tx, they could rapidly identify the frequency used, tune the transmitter to that exact frequency and then connect the Swains Lane Rx to the AP Tx to create a deafening howl round on that frequency, which rendered the navigation system totally unusable. It was a very clever but subtle wheeze and it took the Germans quite a while to realise that the problems were due to British action rather than an inherent fault with their design. If the BBC had not done that, raids such as those on Coventry might have been much more commonplace. That disruption bought time which allowed other defences against bomber raids to become more effective.
I’m amazed at how much material is available on-line for research. Unfortunately much of it is not electronically indexed and has to be trawled through manually, but by following hunches, all sorts of stuff keeps cropping up.
Pat Heigham
Your mention of Marconi engineers reminded me that when movies became ‘talkies’, the sound guys were Marconi men, as no one else had a clue about sound. This could have been the reason that there was such antipathy between the camera and sound departments in the film industry (I thought it stemmed from the sound department insisting on shutting the camera into a sound proof booth! I believe that the scenes depicted in “Singin’ in the Rain” are pretty accurate).I worked for a Production Mixer on a couple of major features, and only discovered much later that he had been instrumental in working on Radar during the war – sadly he’s gone upstairs, so can’t ask him about it.
I recall a story about an OB radio link between North Wales and Morecombe(?) across the water. All fine during rehearsal, but come the transmission, the tide had come in and bounced the signal off line!
I once had a location practically under the Crystal Palace mast. Supplied with a Sennheiser 805 by the hire firm booked by the production, I had the greatest trouble with interference as the mic has an RF stage in the head amp. Careful orientation lessened the effect, but it made operation very tricky.
