The Battle of the Radar Nets over Western Europe: 1944-1945

[Conslaw]

After the invasion of France, the Western Allies advanced across the Western Front in fits and starts, but as they advanced they established airfields and a network of radar stations on the continent. These new radar stations were close to established German radar sites, so planes over the front and well behind each other's lines were within the zone of both friendly and hostile radar. What were the tactical implications of this?

 

[Peter Gunn]

Well, if Joe Pilot took a frozen lasagna up in his Mustang, he might be able to microwave it by staying perfectly aligned with both enemy and allied radar waves...

 

[pbehn]

The Germans operated a passive system that used Chain Home signals.

Klein Heidelberg - Wikipedia

en.wikipedia.org

 

[buffnut453]

Well, if Joe Pilot took a frozen lasagna up in his Mustang, he might be able to microwave it by staying perfectly aligned with both enemy and allied radar waves...

Yeah...but he'd also be at risk of being unable to have children, unless he was wearing lead underpants. Of course, that upsets aircraft CofG....although it might have improved the balance of the P-39.

It's alright...I'm already wearing my coat. I know when I'm not wanted!!!

 

[Peter Gunn]

Yeah...but he'd also be at risk of being unable to have children, unless he was wearing lead underpants. Of course, that upsets aircraft CofG....although it might have improved the balance of the P-39.

It's alright...I'm already wearing my coat. I know when I'm not wanted!!!

You know the drill pal...

 

[pbehn]

Radar nets had been overlapping and being jammed from shortly after the fall of France.

 

[bada]

A nice read about the ww2 radars and countermeasures can be find found here:

http://www.radarworld.org/radarwar.pdf

 

[MikeMeech]

Radar nets had been overlapping and being jammed from shortly after the fall of France.

Hi
This graphic from 'The Battle of Britain' by Richard Townshend Bickers, page 32 shows both high and low radar coverage extending over the Calais area, indeed any German radar would always be overlapping with British radar coverage:

Even British GCI coverage would overlap with German radar systems, British GCI coverage in 1941 shown on this map from 'Watching the Skies' by Jack Gough:

Radar coverage was moved forward for D-Day with GCI and air search aboard ships to cover the landings, as seen in this photo from 'Radar at Sea' by Derek Howse, page 218:

Mobile sets were then moved ashore and advanced with the allies. I don't think there was a great problem with radars from the allies and Germans overlapping, however, problems arose from ground clutter when based offshore and the large numbers of allied aircraft overhead all with IFF which had to be 'interrogated' by the radar systems. Along with German jamming attempts this did mean there were problems with detecting low flying aircraft especially. On shore the mobile units had to choose their sites carefully to achieve a good performance and would never be perfect of course, but that was not due to German radar 'overlap'.

Mike

 

[pbehn]

Hi
This graphic from 'The Battle of Britain' by Richard Townshend Bickers, page 32 shows both high and low radar coverage extending over the Calais area, indeed any German radar would always be overlapping with British radar coverage:
View attachment 635229
Even British GCI coverage would overlap with German radar systems, British GCI coverage in 1941 shown on this map from 'Watching the Skies' by Jack Gough:
View attachment 635230
Radar coverage was moved forward for D-Day with GCI and air search aboard ships to cover the landings, as seen in this photo from 'Radar at Sea' by Derek Howse, page 218:
View attachment 635231
Mobile sets were then moved ashore and advanced with the allies. I don't think there was a great problem with radars from the allies and Germans overlapping, however, problems arose from ground clutter when based offshore and the large numbers of allied aircraft overhead all with IFF which had to be 'interrogated' by the radar systems. Along with German jamming attempts this did mean there were problems with detecting low flying aircraft especially. On shore the mobile units had to choose their sites carefully to achieve a good performance and would never be perfect of course, but that was not due to German radar 'overlap'.

Mike

Also, those arcs are the effective range a signal could be received at, they obviously transmitted much farther out.

 

[Milosh]

Not the best map.

 

[Milosh]

Diagram to show radar counter measures for Operation Overlord, 5/6th June 1944

https://www.nationalarchives.gov.uk...tern-europe/d-day/docs/defe-2-502-enlarge.jpg

 

[pbehn]

Not the best map.
View attachment 635326

That is a great map of the physical representation on the ground of the schematic of German night fighter defences in the Kammhuber and Himmelbett stations.

 

[Milosh]

Another map, Map of animal-themed code names for German WW2 'Himmelbett' radar stations plus of German fighter-bombers
https://ichef.bbci.co.uk/images/ic/976x549_b/p01z570h.jpg

There is a good web site on German radar defenses but can't find it now.

 

[MikeMeech]

Hi
Maps of the German air defence system are available in numerous publications, for example from page 19 of 'Luftwaffe Handbook' by Dr. Alfred Price:

And page 278 of 'Most Secret War' by R V Jones:

This latter book also has a map of German radar along the coast at D-Day:

These stations were also attacked by allied air power as well as 'spoofed' so degrading the system. The allies started landing mobile radar systems (GCI, air search, AA direction etc) on day one of D-Day, these were of course smaller in size than the fixed radar systems used by both the allies and Germany and would also have been less powerful on the whole.

Mike

 

[Conslaw]

It seems like the tactical aircraft from both sides could be tracked from shortly after they took off; but this really worked against the Germans. The Allies would have thousands of sortees, hundreds(?) of squadrons, taking off from at least a hundred fields at roughly the same time. How do you communicate the overall picture?

 

[JDCAVE]

The longer answer is quite complicated. The short answer is the Germans lost their more forward radar stations and the allies gained radar services as they advanced. The allies used radar on the continent to direct both day and night fighters as well as aniti aircraft batteries towards enemy aircraft to considerable effect. Post war, the British undertook elaborate exercises to understand the German radar services and running commentary using captured stations and operators in Denmark. To this end, they tested the effectiveness of their own countermeasures. They used large heavy bomber formations to test the enemy's defences. I have these post war documents and they make for a fascinating read.

 

[elbmc1969]

The longer answer is quite complicated. The short answer is the Germans lost their more forward radar stations and the allies gained radar services as they advanced. The allies used radar on the continent to direct both day and night fighters as well as aniti aircraft batteries towards enemy aircraft to considerable effect. Post war, the British undertook elaborate exercises to understand the German radar services and running commentary using captured stations and operators in Denmark. To this end, they tested the effectiveness of their own countermeasures. They used large heavy bomber formations to test the enemy's defences. I have these post war documents and they make for a fascinating read.

Please post, if you can!

 

[Snautzer01]

Hi
Maps of the German air defence system are available in numerous publications, for example from page 19 of 'Luftwaffe Handbook' by Dr. Alfred Price:
View attachment 635427
And page 278 of 'Most Secret War' by R V Jones:
View attachment 635428
This latter book also has a map of German radar along the coast at D-Day:
View attachment 635429
These stations were also attacked by allied air power as well as 'spoofed' so degrading the system. The allies started landing mobile radar systems (GCI, air search, AA direction etc) on day one of D-Day, these were of course smaller in size than the fixed radar systems used by both the allies and Germany and would also have been less powerful on the whole.

Mike

Original map of Bodenorganisation Großraum-Nachtjagd Luftflotte Reich can be found Ebay heavy Iron (Tanks Guns Ships Trains)

 

[BiffF15]

It seems like the tactical aircraft from both sides could be tracked from shortly after they took off; but this really worked against the Germans. The Allies would have thousands of sortees, hundreds(?) of squadrons, taking off from at least a hundred fields at roughly the same time. How do you communicate the overall picture?

If your systems could see that far, you would just report all airfields actively launching. Remember, they (the Allies in this case) will assimilate into flights, then squadrons, then start navigating. From nav they will further assimilate into packages, or Divisions. Once into squadrons, depending on German comms, you could easily start talking about where they were off a given point (bearing and range from what is now called a bullseye) which builds all airborne assets situational awareness. Once groups / packages start getting closer, you can switch to giving info in BRA, or bearing range and altitude if you have it, with your aircraft / flight / package being the reference point.

During Operation Southern Watch we would patrol the 32nd parallel. It covered a large swath of southern Iraq, and we usually had 3 bullseyes, called something like Seattle, Chicago, and New York. They were laid out that way so you would know where along the frontier there was activity. Allies could talk about aircraft launching in the vicinity of Berlin, then forming up NE, E, and SE of Berlin, and each with a heading or if holding we would call "marshaling". The key is to break things down into digestible chunks. With datalink these days, you see everything your controller does and it becomes a scope management problem for the fighters (bump / look out too far and you miss the gators closest to the canoe, looking in too close, and you miss setting up for the follow on problems).

Cheers,
Biff

 

[JDCAVE]

Please post, if you can!

Like I said. The answer is quite complicated. The radio countermeasures and bluffing exercises were highly developed during the latter stages of the war, while the German response was at times poor, other times mixed and at other times very good. The following narrative pertains to night operations by RAF Bomber Command, October 1944 through March 1945, which was the period when my father was operational. The aircraft in Bomber Command flew over the UK and on nearly all of dad's raids they flew south right down the centre of England, typically to Reading where they crossed the coast of France on a heading SE. Only on his operation to Bochum, November 4/5, 1944 did they cross the Dutch Coast and the Luftwaffe was ready for them and intercepted them at the Coast and stayed with the Force all the way to the target. 5% of the force despatched was shot down that night. But I digress…

Bomber Command employed a specialist Group (100-Group) the focus of which was to confuse and confound the German Ground Control Interception (GCI). On the raid to Chemnitz, March 5/6, 1945, 11 aircraft from 100-Group formed a MANDREL screen between positions 50o​33'N 06o​00'E and 49o​41'N 06o​00'E from 1855-2050 hours. (Intelligence raid analysis reports and interception tactics. Report No. 31-45. March 5/6, 1945. National Archives AIR 25/788) MANDREL was an airborne system designed to interfere with or "Jam" German Ground-based radar systems. When it was effective, and it often was, German GCI would have a difficult time determining from their long-range radars where the force was, and where they were headed until it the lead aircraft penetrated the MANDREL screen. Note that MANDREL and other 100-Group operations were often times laid on even when there were no major Bomber Command Operations, just to keep the German's on their toes, the Luftwaffe in the air and burning precious fuel. For a detailed description of the "Radio Countermeasures" employed by Bomber Command, see War in the Ether Europe 1939-1945, Radio Countermeasures in Bomber Command, An Historical Note, National Archives, October 1945 AIR 20/8962. Note that as German Ground and Airborne systems could home in on the H2S radar systems carried by Bomber Command, strict signals and radar silence was to be maintained until 5o​30'E on track and switched off at 5o​30'E on track.

On this night, a window-feint Bombing force from 100-Group, augmented with 21 B-24s from the 492 Bombardment Group (USAAF) bombed Wiesbaden between 2001-2008 hours. The purpose of the Window Feint Force was to draw enemy fighters into the air and away from the intended route of the Main Force of Bomber Command that were despatched to attack Chemnitz and Bohlen. In addition, to the Windowing force, three aircraft flew with the force to Chemnitz and JOSTLE was operated on VHF at 1931-2040 hours and HF at 2014-2334 hours (4020 KC/S). JOSTLE was a powerful airborne transmitter designed to interfere with or "Jam" German communications simultaneously across a range of VHF frequencies and making it difficult for GCI commanders to communicate to the Nachtjagd using VHF. (See "War in the Ether".) CARPET was operated on the 515-570 MC/s band at 1934-2332 hrs and PIPERACK at 1945-0008 hours. The purpose of CARPET was to Jam German ground Wurzburg radar, in the 500-580 mc/s band. See "War in the Ether". The purpose of PIPERACK was to Jam German radar, in the 95-210 mc/s band. It was later modified to cover the SN2 AI radar in the 63-93 mc/s band. See "War in the Ether". Two Mosquitoes operated PIPERACK in the Chemnitz/Bohlen area at 2125-2220 hours. In the Bohlen area, three aircraft operated JOSTLE on VHF as well as HF at 1931-2040 and on HF on the 3902 KC/S band at 2041-2104 hours at 2105-2131 hours and 2142-2350 hours; CARPET at 1922-0212 hours at 455-570 MC/S and PIPERACK 1939-0007 hours. AIRBORNE CIGAR (A.B.C.) was operated by 101 Squadron of 1-Group. AIRBORNE CIGAR (A.B.C.) was an airborne monitoring system whereby German speaking "Special Operators" scanned and monitored radio frequencies and alerted the "Y" Service in England on which frequencies the ground systems were to jam. See "War in the Ether". Five patrols of Mosquitoes targeted the response of the Nachtjagd in the target areas, the Frankfurt area between beacons, Bohlen, Chemnitz and over German airbases. (Intelligence raid analysis reports and interception tactics. March 5/6, 1945).

A further source of confusion to the German GCI became apparent when the Main Force of bombers bifurcated in the vicinity of Halle, and the trailing force from 5-Group turned SSE to attack the Oil Plant at Bohlen. This force followed a different and more southerly return route.

The route that night:

March 5-6, 1945 Target Chemnitz - Google My Maps

March 5-6, 1945 Target Chemnitz

www.google.com

So how did this play out? The aforementioned Intelligence raid analysis and interception tactics report above and Boiten and Mackenzie (See Boiten, T and R. MacKenzie. 2008. The Nachtjagd War Diaries: An Operational History of the German Night Fighter Force in the West, April 1944-May 1945. Red Kite. 400 p) outline the following...

The MANDREL screen obscured the initial approach of the two forces, but successful plotting commenced as the bombers crossed the Battle Line. The plotting was confused in the initial stages however and the enemy estimated the target as Mainz and directed two Gruppen of Nachtjagd in that direction. Once Window had dispersed, the position of the force was clarified and continuous and accurate plotting of the two forces flying north easterly towards the Target Areas. At 1942-2002, II NJG.2 was ordered to Elster Beacon and at 2005 was informed the target was Mainz. At 2054-2117 the force was plotted flying towards the target and there were reports of bombs falling on Halle at 2120-2126, but this was rescinded at 2133 and at 2154 bombs were reported as falling on Chemnitz.

Between Andernach (Turning Point "G") and Bad Hersfeld, three bombers were shot down, including possibly 431 Squadron KB.858 which crashed at Oberweidbach at 2020 hours. This aircraft may have been shot down by any one of 3 Nachtjager: Maj Hubert Rauh of II.NJG4, Maj Max Eckhoff of Stab II./NJG2 or Oblt Kurt Matzak of Stab IV./NHG1. Rauh flying a Junkers Ju.88 shot down three bombers with his forward firing cannon 2022-2050 hrs. Oblt Matzak in a Bf.110 shot down a Halifax in the Siegen area at 2030.

By 2020 hours, the German controller had realized that the large Chemnitz/Bohlen force was a major threat and the stream was systematically and accurately plotted and regular updates were sent to the Nachtjager. By 2035 hours, III.NJG.4 received plots of the force in the area NE of Erfurt and also II./NJG2 at 2054 hours. At least another six bombers were shot down at 2036-2115 hours, between Bad Hersfeld and Aschersleben. These included Lancaster PB.557 from 460 Squadron, Halifax NR.131 from 10 Squadron and 103 Squadron Lancaster PB.563. As the force separated NW of Halle towards the targets of Bohlen and Chemnitz, two bombers were lost (including 426 Squadron Halifax, NP.799) as they collided at turning point "I".

Over the Target Area and on the return route, Boiten and Mackenzie relate the following details about the battle between the Bomber Command force with the Nachtjagd. The Chemnitz force received most of the attention from the Nachtjagd, particularly from NJG5 in force in the Target Area from 2152 some 15 minutes after the bombing had begun, with at least six bombers lost in the Chemnitz area at 2150-2210 hours. Two Lancasters (from 424 and 170 Squadrons) collided, and another four Lancasters from 425, 35, 576 and 635 Squadrons were shot down, likely as a result of fighter attacks. A 192 Squadron Halifax had completed its bombing run at 2150 hours when it was attacked by a Ju.88. During a corkscrew manoeuvre, it collided with another bomber (possibly 434 Squadron Lancaster KB.842). Control of the Halifax was regained although it had lost five feet of its nose. The Ju.88 made two more attacks. The pilot decided to head towards Soviet lines and crashed near Kety Poland, some 290 miles E of Chemnitz. Lancaster KB.842 was attacked by another Ju.88 and received heavy damage. It managed to limp home to the UK where it was written off after crash-landing. Along the homeward route from turning points "K" and "L", three Lancasters and one Halifax were shot down by the Nachtjager: 625 Squadron Lancaster PD.375 crashed near Scharzenberg following a night fighter attack, 153 Squadron Lancaster PB.872 crashed near Rossbach. Halifax RG.502 from 102 Squadron crashed near present day Nova Viska and 625 Squadron Lancasters NG.240 crashed near Kovarska at 2142-2210 hours. RAF Bomber Command losses over the continent amounted to thirty-one aircraft: Twenty-two bombers from the Chemnitz force and five from the Bohlen force. A further two Mosquitoes and one Halifax and one Stirling from 100-Group were lost. The Nachtjager claimed nineteen bombers including five by Major Eckhoff. Twelve Nacthjager were lost, including aces Geschwaderkommodore Obstlt. Walter Borchers, who was shot down by a mosquito flown by W/C Gibb DFC of 239 Squadron, and Maj Hans Leichhardt of Stab II.NJG5. It is unclear if this loss was due to return fire from a Bohlen raider or was the second aircraft shot down by W/C Gibb.

A total of 683 aircraft successfully bombed Chemnitz and a further 6 bombed alternate targets. There were 31 abortive sorties (including Cat "E") and 20 aircraft were missing. Photographic reconnaissance on March 7 and 15, 1945, which included several USAAF raids March 2, 3, and 5, 1945, indicated the old town and areas surrounding it stretching to the north as far as the main railway centre were completely devastated. Many factories south of the town were severely damaged and there was some damage to the railway facilities. The attack on Bohlen was not a success.

Dad remembered "We lost one aircraft; Flying Officer Reitlo was killed and he had flown 2nd dickie with me to Duisburg on February 21st. The poor bugger didn't last very long. I think he had six or seven trips and that was all. So, the morning of the 6th found us back in Middleton St. George, after ten hours and fifteen minutes, finishing our 27th trip."

Edit: I have a number of wartime and immediate post war documents on 100-Group and radio countermeasures. There is an excellent PHD thesis by Thomas Withington, 2017, BOMBER COMMAND'S ELECTRONIC WARFARE POLICY AND SUPPRESSION OF ENEMY AIR DEFENCE POSTURE DURING THE SECOND WORLD WAR, University of Birmingham.

https://etheses.bham.ac.uk/id/eprint/8076/1/Withington18PhD.pdf

Jim