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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

Carnaby
14-09-2009, 15:08
Two links

Picture (http://serialconsign.com/images/2008/07/knickebein.jpg) of a Knickebein Aerial, Article (http://s110605900.websitehome.co.uk/beams/beampage.htm), with drawing

Just noticed the TNA lat/long for 'Whitlands' above is wrong. The NGR for the hamlet (not the RTG) is SY306911, approx 50/42N 2/59W

Graham

PNK
14-09-2009, 21:03
Carnaby, Lyme Regis seems to have shifted a bit north!

I also had a quick look for any signs both on GE and the last few decades of OS maps but nothing is shown.

Any idea how big the site would have been in plan form? I assume a good quality air photo would show one up but the online versions are a bit muddy for detecting lattice shadows.

Carnaby
14-09-2009, 21:23
Carnaby, Lyme Regis seems to have shifted a bit north!
Any idea how big the site would have been in plan form?.

Error now corrected above - your message slipped in just I was correcting the reference!. There is only one TNA file relating to J Beams. I wonder if they were dismantled soon after the jamming began - possible by 1943?

Graham

PNK
14-09-2009, 23:00
There is only one TNA file relating to J Beams. I wonder if they were dismantled soon after the jamming began - possible by 1943?

Depending on how the land was aquired I suppose it could have all gone by the time the 1947 National Aerial Survey began hence invisible.

The sites could also have been reused for other purposes and therefore look entirely different.

RadarArchive
09-05-2010, 21:03
I think I may have located the remains of the one at Ravenscar, which is a very large circular pad, surrounded by a fairly low brick wall. I was never sure exactly what it was, but it sounds like it could be this. I have some photos of the remains, but haven't scanned them. I have found an aerial photo in Bing maps, but don't know how to link to it.

Cheers,

Ian

Carnaby
09-05-2010, 22:02
Ian, could you supply the NGR for the site - sounds promising?

Graham

David Thompson
09-05-2010, 23:24
The circular pad is at MR94/973013 . There is a radio mast very close to the NW and also some wartime concrete hardstandings . I visited this area last month and the view from here is excellent and well chosen as the site for a radar station.
This station is mentioned in the book Halifax Squadron, the wartime bombing operations of 640 Squadron, self published by Bill Norman . He quotes a then wireless mechanic at the RAF's Radio Track Guide Station Ravenscar as working with a Swab transmitter and also a Darkie TR9 set , the latter being used to give a bearing and distance to a prominent local feature, usually Scarborough.
Just down the coast at Bent Rigg Farm are the remains of a CHL radar station with several buildings still remaining; MR94/992008.

RadarArchive
10-05-2010, 06:14
Just down the coast at Bent Rigg Farm are the remains of a CHL radar station with several buildings still remaining ; MR94/992008 .

Just a small point of pedantry. The site was not CHL but rather CD/CHL. Although it operated on a 1.5 metre wavelength, it had a different primary function and used very different structures.

The map reference is indeed the structure I was referring to. The pad must be about 30 feet in diameter.

Cheers,

Ian

Carnaby
10-05-2010, 10:54
The RTG site is HERE (http://wtp2.appspot.com/wheresthepath.htm?lat=54.39659113635884&lon=-0.5038807683494241&gz=19&oz=8&gt=1), and the second site is HERE (http://wtp2.appspot.com/wheresthepath.htm?lat=54.39276817062671&lon=-0.4756253957748413&gz=18&oz=8&gt=1)

Thread on second site HERE (http://www.airfieldinformationexchange.org/community/showthread.php?4523-Ravenscar-Bent-Rigg-Farm-CD-CHL&p=45215#post45215)

OT but referring to David's post #8, I guess the Swab was a Marconi SWB (short-wave broadcast) device manufactured in many forms. The BBC used 100kW versions for their Overseas Service during and after WW2. A few links - Dorchester Radio Station (http://www.gb4imd.org.uk/dorchester.htm), SubBrits Ongar site (http://www.subbrit.org.uk/sb-sites/sites/n/north_weald_ongar_radio/index.shtml), SWB type 8 (http://www.airwaysmuseum.com/Museum%20SWB8.htm)

Graham

Carnaby
28-09-2010, 11:42
South Barrule was a Radio Track Guide in the Isle of Man.

Spelled as South BarrOle the location was 54-08-11N, 04-28-25W

It appears to be here (http://wtp2.appspot.com/wheresthepath.htm?lat=54.13669115618941&lon=-4.70647796251066&gz=18&oz=8&gt=1), and was still active 5 July 1946.

The beam was almost north/south and ran very close to West Freugh and Valley. The line of the concrete is consistent with a N/S beam. Another site at Llangollen had a beam which intersected South Barrule.

Llangollen's seems to be here (http://wtp2.appspot.com/wheresthepath.htm?lat=53.025720045229505&lon=-3.201566103007881&gz=18&oz=8&gt=1) at 53-01-32N, 03-11-58W. Again, the angle of the concrete looks about right.

Source: AIR20 / 6147 Radio Track Guides Scheme in the British Isles: policy

A number of other sites have been 'Google Mapped' with no remains.

Graham

Carnaby
28-09-2010, 14:34
The South Barrule RTG beam had a marker beacon at Llanfaelog, just to the south of RAF Valley. Location given is 53-13-5 N, 04-28-25 W, which puts it about here (http://wtp2.appspot.com/wheresthepath.htm?lat=53.218251305267735&lon=-4.474957287311554&gz=19&oz=8&gt=1). Though I guess this is something else, the orientation of the perimeter fence (a few degrees west of a N/S E/W box) seems more than coincidental as it lines up with the beam angle.

If anyone ever gets up there it may be worth checking. A Google Street view is here (http://maps.google.co.uk/?ie=UTF8&ll=53.218497,-4.477712&spn=0.004375,0.013733&t=h&z=17&layer=c&cbll=53.218588,-4.475655&panoid=hVTXaK8odFXWVJuIQw5C-w&cbp=12,122.71,,1,1.31).

Graham

Dave Smith
28-09-2010, 18:57
The location of the Llangollen RTG site is close to the Ponderosa Cafe, a popular spot on the Horseshoe Pass road. While walking around there about 20 years ago, I found concrete blocks which appeared to be aerial anchorage points. Thanks for identifying what it it was all about!

canberra
28-09-2010, 19:18
I hadnt heard of this sort of system before, it strikes me as a very early form of eureka which then gave birth to TACAN.

Carnaby
28-09-2010, 19:42
I hadnt heard of this sort of system before, it strikes me as a very early form of eureka which then gave birth to TACAN.
The main difference between RTG and the later Eureka / TACAN systems was that in RTG the ground station sends out the beam and the aircraft is purely passive. In other systems the aircraft and ground station 'electronically talk' to each other.

The RTG stations in 1946 were:
Spitalgate
East Kirkby (called East Kirby)
Lindholme
Tadmarton
Marlborough ?
Church Lawford
South Barrule
Prestwick
Llangollen
Okehampton ?
Hendon
Northolt
Lat/Long for some are available - nothing on Bing or GE, other than the ones mentioned above. Italics denotes intended stations.

Graham

kebecker
28-09-2010, 20:07
Graham

do you have the latÚlong for Spitalgate╔

Sorry about the question mark I have a damn biligual key board and have no idea how to get some of the symbols to appear, and I am to lazy to go to the control panel!

Carnaby
28-09-2010, 20:12
lat/long for Spitalgate

552-54-30N 00-36-34W I note from the three I found the site is a short distance away from the precise reference. Good hunting

Graham

kebecker
28-09-2010, 20:42
this farm is in about the right place, to the north of the airfield



http://maps.google.com/maps?t=h&hl=en&ie=UTF8&ll=52.908915,-0.601587&spn=0.005992,0.02105&z=16