Carnaby
14-09-2009, 12:44
Homing Beams (with dots to the left, dashes to the right), used by the RAF in WWII were of three types:
1) Standard Beam Approach - a low-power 360 degree beam to get an aircraft on to an airfield's runway.
2) Radio Track Guides (RTG) - a powerful long-range narrow-angle beam to get the aircraft to a particular location.
3) 'J' Beams - similar to the above.
An excellent example of (2) was via the Medium Frequency 'Leader' beacon at Derrynacross / Lough Erne which UK bound aircraft could pick up over the Atlantic. Once over Ireland aircraft could then pick up the RTGs from Prestwick, Squire's Gate, Silloth and Valley.
'J' Beams were RTG transmitters located in the UK beaming a homing signal into enemy occupied territory. Their main function was to confuse the Germans and hopefully throw them off the scent of the RAF's new GEE navigational system (The 'J' was deliberately chosen as it is very phonetically similar to 'GEE'). The beams were rotatable, and for a long period were used successfully by the RAF to find their way back to the UK.
I haven't found a photo of one, but they would be similar to the Luftwaffe's Knickebein aerials - a huge turntable-mounted array, several metres high and tens of metres in width to produce the required narrow beam.
They became operational between May and September 1942, and there is evidence that Luftwaffe Signals spent some effort in jamming them, whilst ignoring the important GEE transmissions. They were evidently flattered that the British had copied an valuable German invention!
From AIR14/1257, the known stations were:
A Ravenscar (Yorks) 54/24 0/30
B Cransford (Framlingham) 52/13/37 1/23/03
C Fulstow (N. Coates) 53/27/11 0/0/41
D Haine (Ramsgate) 51/21/26 1/23/14
F Whitlands (Lyme Regis) 57/41 2/03
J Sandhaven (Fraserburgh) 57/41 2/03
Lat/long co-ordinates given - not sure about stations E, G-I (if they existed). I couldn't easily locate any of the sites in Google Maps etc. (A challenge for someone :-D)
The other Air Ministry ruse to confuse the enemy scientists was by allocating misleading type and serial numbers to the aircraft electronic equipment. Hence T/R 1234 wasn't necessarily a Transmitter-Receiver. The Germans were naturally scrupulous in their numbering which was of great assistance to British engineers. A Luftwaffe transmitter type '1234' was definitely a later version than a type '1233', and serial number '999' was definitely manufactured before '1012'. This was not to be the case with later British equipment.
Graham
1) Standard Beam Approach - a low-power 360 degree beam to get an aircraft on to an airfield's runway.
2) Radio Track Guides (RTG) - a powerful long-range narrow-angle beam to get the aircraft to a particular location.
3) 'J' Beams - similar to the above.
An excellent example of (2) was via the Medium Frequency 'Leader' beacon at Derrynacross / Lough Erne which UK bound aircraft could pick up over the Atlantic. Once over Ireland aircraft could then pick up the RTGs from Prestwick, Squire's Gate, Silloth and Valley.
'J' Beams were RTG transmitters located in the UK beaming a homing signal into enemy occupied territory. Their main function was to confuse the Germans and hopefully throw them off the scent of the RAF's new GEE navigational system (The 'J' was deliberately chosen as it is very phonetically similar to 'GEE'). The beams were rotatable, and for a long period were used successfully by the RAF to find their way back to the UK.
I haven't found a photo of one, but they would be similar to the Luftwaffe's Knickebein aerials - a huge turntable-mounted array, several metres high and tens of metres in width to produce the required narrow beam.
They became operational between May and September 1942, and there is evidence that Luftwaffe Signals spent some effort in jamming them, whilst ignoring the important GEE transmissions. They were evidently flattered that the British had copied an valuable German invention!
From AIR14/1257, the known stations were:
A Ravenscar (Yorks) 54/24 0/30
B Cransford (Framlingham) 52/13/37 1/23/03
C Fulstow (N. Coates) 53/27/11 0/0/41
D Haine (Ramsgate) 51/21/26 1/23/14
F Whitlands (Lyme Regis) 57/41 2/03
J Sandhaven (Fraserburgh) 57/41 2/03
Lat/long co-ordinates given - not sure about stations E, G-I (if they existed). I couldn't easily locate any of the sites in Google Maps etc. (A challenge for someone :-D)
The other Air Ministry ruse to confuse the enemy scientists was by allocating misleading type and serial numbers to the aircraft electronic equipment. Hence T/R 1234 wasn't necessarily a Transmitter-Receiver. The Germans were naturally scrupulous in their numbering which was of great assistance to British engineers. A Luftwaffe transmitter type '1234' was definitely a later version than a type '1233', and serial number '999' was definitely manufactured before '1012'. This was not to be the case with later British equipment.
Graham