Mow Cop and the Battle of the Beams
During the first few months of 1940, information gathered by decoding Enigma radio traffic,
the interrogation of captured aircrews and evidence which was gathered by airborne radio
monitoring, revealed the existence of a German radio navigational beam system. This was
being used by the German aircrews to accurately locate targets over the British mainland.
The first system to be discovered was named Knickebien (translated as Crooked Leg) by the Germans and had been developed from the widely adopted Lorenz aircraft blind landing system. A simple but effective countermeasure was urgently needed to prevent the German aircrews from using the system or at least to confuse the navigational information.
A system of radio 'jamming' was developed using hospital Diathermy sets which were quickly converted into transmitters and placed at various locations such police stations and public buildings. These transmitters would only be switched on when an air raid was imminent, so as to prevent the Germans from easily discovering that we had found the 'beams' and that we were taking preventative action.
X-Gerate was the next system to be used by the Germans. It was very similar in principle to Knickebien, but proved to be a more refined and accurate system needing sophisticated countermeasures. It was to be countered by using specially developed 'jamming' transmitters called Bromides, a name presumably chosen because it was to render X-Gerate impotent.
The task of setting up these 'jamming' stations fell on the newly formed RAF 80 Wing, Radio Counter Measures, whose base was at Radlett in Hertfordshire. Following the earlier attempts at 'jamming' using converted Diathermy sets, purpose made and more sophisticated jamming equipment was developed. These purpose made 'jamming' transmitters were known as ' Aspirins', a cure for the 'headache' that the system had posed to us.
In the early days of the 'battle of the beams', some 28 of these Aspirin transmitter sites were set up. Some were mobile units, the remainder were installed permanently on high ground.
Mow Cop became one of the permanent sites, chosen for it's unhindered coverage of the major industrial targets of the North West, from Trafford Park and other industrial areas of Manchester to the Liverpool docks and beyond.
Confusion surrounding the exact location of this site came from the account by Brian Johnson, who in his BBC book 'The Secret War', gave the location as Kidsgrove, Nr Crewe.
Mow Cop at that time was part of the Kidsgrove Urban District, the most likely cause of the wrong location being cited.
During October 1940, the Air Ministry requisitioned a meadow just of Congleton Rd, Mow Cop to set up the transmitter station. They soon began to install the equipment with the erection of two tall masts, several permanent huts, underground cabling and most significant, a sentry post to prevent unauthorised access. As with other jamming stations throughout the country, the local population would speculate as to the stations purpose. Was it for aircraft counting and spotting, some form of radio detection or a listening station etc. What was it for? It would not be until the mid 1970's that the true nature of it's purpose would be revealed. The Mow Cop site was fully manned by 80 wing personnel for the remainder of the war.
On the night of the bombing of Coventry, 14th and 15th November 1940, only six Bromide stations had come into operation, Mow Cop being one of these. Although Mow Cop would certainly have been to great a distance from the target to effectively jam the X-Gerate signals, the choice of it as one of the first six sites must demonstrate the importance that 80 wing attached to it as a jamming station. As it was eventually discovered, some unknown technical aspects of the jamming signal would have prevented it from being effective on that night anyway.
One of the RAF personnel stationed at Mow Cop was Mr. Jim Hickman. At the outset of war he was living at home in Harriseahead, and on joining the RAF was sent to train on radar. It must have been a surprise to say the least when he was given a chitty instructing him to report to the Mow Cop site which was only two miles from home. He was to spend the next two years carrying out his top secret work whilst being able to live at own home.
Another RAF man who served at Mow Cop between 1941 to 1943 was Mr. Cyril Fisher, who on arrival at his new posting in the middle of winter, chose to leave his train at Mow Cop station and was confronted by the arduous journey up the hill, carrying a full kitbag.
In a series of articles in the Congleton Chronicle, A J Condliffe tells us of the time that the jamming was so successful that German bomber crews missed the targets totally and carried on to Ireland before releasing their bombs. Mow Cop of course, got the blame. This and other incidents were confirmed as true by Jim Hickman and Cyril Fisher. A J Condliffe also tells of at least four RAF personnel who met and married local girls.
If anyone has some additional information or experiences of the RAF at Mow Cop, I would be extremely pleased to hear from you. Does anyone remember the two tall masts?
The story of the 'battle of the beams' is quite involved but extremely fascinating and is covered well in Brian Johnson's book, 'The Secret War' (published by BBC books - 1978)
A more personalised account of the events by the wartime scientific advisor R V Jones, can be found in his book 'Most Secret War'.
For more information, click on the link below for a good explanation of the beam systems. They are demonstrated using excellent graphics.