Friday, April 29, 2011

Fallschirmjäger Artillery during Operation Merkur (Mercury), Crete 1941

I only have a very limited knowledge of WWII German Airborne Forces, my primary area of interest being the British Parachute Regiment and Airborne Forces. I’m not certain of the origin of these photographs but believe them to be personally taken (or had taken) by a Fallschirmjäger Hauptmann (Captain) in an artillery unit assigned to the XI Fliegerkorps (Air Corps). Based on available Order of Battle data it is highly probable that it is Fallschirmjäger Artillery Section 7. The photos depict both the 10.5 cm L.G. (Leichtgeschutz – Light Gun) 40 (105mm Airborne Recoiless Rifle) and 7.5 cm Geb. G 36 ( Gebirgskanon -75mm Mountain Howitzer) in action in Kreta (Crete) during Operation Merkur (Mercury) in 1941. Both recoiless weapons were organic to the TO&E of artillery elements assigned to the Flieger-Division. However, confusion arises due to the same designation, L.G. 40, being given to both a 7.5cm and 10.5cm recoiless rifle. The Flieger-Division was also equipped with the 3.7 cm Pak (37mm Antitank Gun) which was motorcycle towed. The 75mm Mountain howitzers were organic, in 2 Sections (6 guns/section), to the Gebirgs-Artillerie-Regiment 95 (Mountain Artillery) of the 5th Gebirgs Division.

The SdKfz 2 Kettenkraftrad, which was initially designed as a light tractor specifically for the fallschirmjäger, can be seen in the photos as the prime mover for the Geb. G 36 ( Gebirgskanon -75mm Mountain Howitzer). Also seen in one photo are the Sd.Anh. 1 special trailers supplied with the SdKfz 2. Based on the photos it appears that the 750 ccm  BMW R75 Kraftrad (motorcycle) was sufficiently powerful to be used as a prime mover for the L.G.40 recoiless rifles.

Based on the limited view the radio set shown in the one photograph is probably the two-man pack Transceiver (Torn. Fu. a2). The set had a 1 watt power output, giving a range of 9 mi for CW mode and 4 mi for radio/telephone; based on data contained in TM-E 30-451, HANDBOOK ON GERMAN MILITARY FORCES, Department of the Army, 15 March 1945 issue. This particular radio set was standard for communications between infantry regiment (brigade) to battalion, and from battalion to corps.

Both the DFS 320 gliders employed in the invasion of Crete, and the GO 242 subsequently introduced in 1942, primarily as a supply glider on the Eastern Front, can be seen.

It appears that the photographs were taken both during the course of the battle in Crete, as well as the return to depot in Germany.

In several of the photos it can be seen that the captain is wearing the Iron Cross 1st Class, and Luftwaffe Pilot’s badge in addition to his Luftwaffe Parachutist’s badge. In one photo he appears to be talking with Reichmarschall Herman Goring.

A study titled, AIRBORNE OPERATIONS, A German Appraisal, CMH Pub 104-13, U.S. Government Printing Office, 1989, was written for the Historical Division, EUCOM, by a committee of former high ranking German Luftwaffe officers. The list reads like a who's who of the Fallschirmjäger. It follows an outline prepared by the Office of the Chief of Military History, Special Staff, United States Army, and can be read in its entirety at In that assessment the following was stated regarding the employment of artillery by the Fallschirmjäger during Operation Murkur. It was written by Oberst (Colonel) Freiherr von der Heydte (awarded Knight's Cross with Oak Leaves of the Iron Cross for action in Crete), an outstanding field commander of German parachute troops.

'The greatest headache for the German paratroop command was the lack of artillery in support of infantry fighting. The German paratroops were equipped with the excellent 75-mm. and 105-mm. airborne recoilless guns; both had short barrels and carriages made of light metal alloy. In suitable terrain the 75-mm. gun could be easily drawn by two men, and its elevation was the same as that of the 37-mm. antitank gun of the Army. The maximum range was 3,850 yards for the 75-mm. gun and 9,000 yards for the 105-mm. gun. Both had the following disadvantages:
a. A large amount of smoke and fumes was generated, and the flash toward the rear was visible at night for a great distance.
b. They could be used only as flat-trajectory weapons. Attempts to use the airborne recoilless guns as high-angle weapons were not satisfactory. Moreover, in an airborne operation it was seldom possible to carry along the necessary amount of ammunition or have it brought up later. Thus, as a rule, only important point targets could be attacked with single rounds, generally from an exposed fighting position.
Besides these weapons, 150-mm. rocket projectiles were used in the Crete operation. They were fired from wooden carrying crates, which also served as aerial delivery containers. These rockets did not prove successful; because of their high degree of dispersion they were suitable only for use against area targets and in salvo fire. However, the quantity of projectiles needed for such a purpose could not be transported on an airborne operation, and a Junkers JU-52 (German troop carrier aircraft) could carry and drop only four projectiles at a time.'

Oberst Freiherr von der Hydte
Commander of 1st Bn 3rd Fallschirmjäger Regt
at Crete

Sunday, April 24, 2011

WWII British Special Forces Night Vision Technology - "TABBY" RG Receiver

In a couple of blogs I have briefly discussed the WWII vintage British Type K Monocular “TABBY” Night Vision Device, also known as the Receiver, RG (‘Red-Green’ Infrared, O.S. 960 G.A., ZA 23119), and its use by British Special Forces.

These receivers were employed by Combined Operations Pilotage Parties (COPP's) from1942-1945; contained then state-of-the-art technology, equipment was 'top secret' until March 1944. existence of  COPP's was classified under the Official Secrets Act until 1957; Ministry of Supply acceptance label is present, signed and dated 27 Apr 1944, with inspector's Stamp Crown/R86 and No. 1004; identical units extensively employed at Normandy, D-day 6 June 1944. My principal interest in the receiver is historical rather than technical, but as an engineer I had done limited work on laser designators and fire-control systems (Honeywell SEAFIRE System in late 70's).
In and amongst more recognizable weaponry is the Type K
"TABBY" RG Infrared Receiver which appears as a WWII
British water bottle with an off-set top. Click on image for
enlarged view (from author's personal collection)
As can be inferred, the receivers were employed in the night operations of the  COPPist swimmer-canoeist teams. They were principally used to aid in recovery on-board the mother Royal Navy submarines from which they had launched, following the completion of their mission in assigned operational reconnaissance areas. The submarine carried an infrared transmitter lamp (Aldis-type, but invisible to the naked eye) in the 750 - 950 nm IR wavelength, and the CV-143 receiver tube operated in the same frequency range.

The following photographs are of a WWII Mark 9 Powered Aluminum Sectional Bulkheaded Canoe where else, but in an English Garden! A similar, but simpler 'Cockle', specifically the Cockle Mk 1** was used by the COPP's. Variants were also used by the Special Boat Squadron (SBS) and Royal Marine Boom Patrol Detachment (RMBPD) swimmer- canoeists in their operations. The craft is 18 feet long and had a 28 inch beam in order to permit passage through the diameter of a submarine hatch as well as interior passageways.
WWII Mk 9 Powered Aluminum Sectional Bulkheaded Canoe;
 Note relatively large tiller and port side sponson, matched by
 a starboard sponson (not visible), for added stability in an
 ocean environment
Same craft from the bow; Note components of mast providing
 for a use  of a latin sail, weather and security conditions permitting
Latin sail and mast assembly
Historical Background
The receiver represents the genesis in the application of infrared technology to military night vision. The primary infrared tube was first manufactured in 1939 and incorporated in this receiver as a military night vision device. It preceded the American M2 Sniperscope by four years.

In the history of war technology, this is Ground ZERO for night vision development. This British Infrared Image Tube was manufactured in 1939 for use in the SUPER SECRET "Tabby" or the OS 960 GA.ZA 23119. The world's FIRST Military "see in the dark, infrared night vision device!" This unit preceded the American M2 Sniperscope, which was first issued in 1943 by four years. Incredibly, this 65 year old electronic marvel is still functional. This is an absolutely amazing piece of technological and military history!
Various views of the Type K "TABBY" RG Receiver and
Carrying Case, showing acceptance label dated April 1944,
two months before D-Day
The ability to see in the dark, with no visible light, was a chance discovery from early Farnsworth television camera which were still in their infancy. Were the U.S. and Great Briton sharing this technology? Not likely. This was one of the most protected secrets of World War Two. It was classified "Top Secret" information. Even 10 years later in the Korean War, great secrecy surrounded the improved American M-3 Sniperscope. Strict instructions on how to destroy and bury the device were given in the technical manual so the device would not fall into enemy hands.
Night view as seen through RG Receiver using
only available light
Physical Description
The infra-red receiver tube is designated CV143 and is 41mm in height and 48mm in diameter. Operational parameters and characteristics of the tube, to extent known, are discussed below. This early technology is known as “0” generation. The tube and its battery power supply were sealed/soldered into the outer container (waterproof), which closely resembles a WWII British Army water bottle (canteen). A khaki canvas covering fastened over the unit, providing better handling in a marine environment, further conveys the impression of a water bottle. The unit weighs 3.0 pounds. The monocular eye-piece has a marked focusing adjustment with a range from '0' to about '3', but with only the numeral '2' showing, along with tick marks. Although the tube is installed in this specific unit, photographs of another disassembled tube show the serial number is hand written onto the glass with India ink. A super high tech, high voltage coating of beeswax is still on the glass barrel of the tube.
Sealed CV 143 Infrared Receiver Tube as integrated
into the type K "TABBY" RG Receiver circa 1944
Sealed CV 143 Tube showing the receiver lens
Complete Type K "TABBY" RG Receiver
unit showing resemblance to WWII British
water bottle
References to the Unit and its Employment
COMMANDOS AND RANGERS OF WORLD WAR II, J. Ladd, St. Martin's Press, New York, 1978; pp.59, 60, 62, 63, 67; SBS IN WORLD WAR II, G.B. Courtney, Hale, London, 1983; pp.5-6, 57; SBS THE INVISIBLE RAIDERS, J.D. Ladd, Arms & Armour Press, London, 1983; p.20, also see BRITISH SPECIAL FORCES, W. Seymour, Sidgwick & Jackson, London, 1985; p. 112-113 AND STEALTHILY BY NIGHT, I. Trenowden, Cercy, Midsomer Norton, Avon, 1995; p. 11, 27, 60, 62.

In STEALTHILY BY NIGHT; 'practiced launching, canoeing, swimming and recovery, camouflage and infra-red torch visibility trails. They bought privately most of the gear required and succeeded in getting two of the first infra-red transmitters and receivers in existence loaned to them. These had been produced for the RAF. Their principle is identical to the modern high-technology Infra-red light beacons, used by downed Tornado pilots in the Gulf War. Infra-red emissions, invisible to the naked eye; though visible to the pilot of a CSAR (Combat Search and Rescue helicopter) wearing night glasses. Or in the Case of the COPP RG ('Red-Green') seen through the glass of the receiver.'

In COMMANDOS AND RANGERS OF WORLD WAR II; 'RG Equipment: RG was a code name for a system of signals sent by a special lamp and received by a screen in a camera-like box. The receiving equipment included components capable of forming pictures and indicating the line of development for a gunnery night-sight, therefore the equipment was 'top secret until March 1944.'

In SBS IN WORLD WAR II: 'and the infra-red signaling gear. This RG equipment sent a beam of invisible infra-red light from an Aldis-type lamp, the signal being visible only when the beam was on a little black box-camera (actually olive-drab) with a screen, which when the beam was intercepted, showed a green spot against the speckle of green pin-pricks of infra-red light from the stars.'

Generation 0 Device Theory and Operation
Devices of this generation have so little low light amplification that as a rule more strongly, additional IR-illuminators must be used for observation. Therefore they are also called 'active night vision devices'. Basically in contrast to the other generations a transformation instead of an intensification of (IR-) light is achieved (one speaks here rather of image converter tube than an image intensifier tube). By the use of an IR-illuminator the user has mostly two crucial disadvantages: On the one hand the observation duration is depending on the usually big and heavy power source and on the other hand the user of such a strong illuminator is visible to other distant NVD-users (no real covert operations possible). The advantage of image converter tubes of the Zero Generation is a wide sensitivity in the deep infrared range (absolutely invisible illuminators can be used). The construction principle of the image converter tubes goes back into the 30's.
Structure, image converter tube:
* S-1 photocathode, coated with silver shifted cesium oxide
* Anode cone, ensures over high voltage acceleration focusing and turning the image (i. stands within the tube up-side-down)
* P1 phosphor screen, coating out of zinc and cadmium transferred phosphor
An automatic protection of the photo-sensitive tube does not exist (danger of damage with bright light, e.g. car headlights). Due to the chemical characteristics of the coatings a clear afterglow (of bright objects) is visible and the life span (service life) is limited.
If the user does not depend on the handiness of a system and do not mind their own IR recognizability, these devices are for instance well suitable for wildlife observations, although they are considered technically as outdated. The main working range of this generation is between 750 and 950 nm wavelength.
Schematic cross-section of CV 143 tube with basic
elements identified
If anyone might want additional technical data it can be found at; In addition please refer to another page in this same blog for an addendum to this page which describes a variant on the 'Tabby' IR receiver, the Type "CX" AN 24 A.P.W. 6815x, including detailed disassembled photographs of the receiver showing both the CV-143 tube and battery pack. 

Thursday, April 21, 2011

Communications at the Battle of Arnhem

In February 2004, on the occasion of the 60th Anniversary of the Battle of Arnhem, John Berry, the Managing Director of radiocommunications specialist ADTI, Ltd., conducted an in-depth technical analysis and published a White Paper entitled, ‘Communications at the battle of Arnhem: A modern day technical analysis’ which can be found at: Subsequent to the publication of that analysis, and drawing upon its findings, Maj John Greenacre of the British Army published a paper entitled, ‘Assessing Reasons for Failure: 1st Airborne Division Signal Communications during ‘Operation Market Garden” in the journal, Defence Studies of Autumn 2004 which can be found at:

It is hoped that most readers will acknowledge that ranked even higher than logistics and intelligence, effective communications has been and remains, the most important element of warfare.

Without going into the in-depth details of each author’s analysis (which those interested certainly can do using the cited URLs), two fundamental concluding points are made.
The first, by Perry, being that the technical performance capabilities of the two major wireless sets employed, the Wireless Sets No.22(vehicle borne) and No.68(man-pack) were capable of achieving a range of > 6 to 10db signal to noise ratio (modern military communications planning uses a 13db ratio as excellent) sufficiently adequate for reliable voice communications from the on-set of operations on September 17, 1944.

British Army Wireless Set WS No. 22 circa 1944 (with credit
to Pye Telecom Historical Collection)

Another view of a Wireless Set No. 22 (with credit to Peter PAOPZD
at Signals Collection)

Maj Greenacre’s analysis concurs with this assessment, He attributes the failure to lack of implementation/maintenance of correct communications procedures by commanders and signals staff of the 1st Airborne Division. He further states, ‘Many risks were accepted during the planning of Operation ‘Market Garden’. One of those risks was that communications for 1st British Airborne Division would be stretched. Deane-Drummond advised Divisional HQ of the difficulties that were likely to be encountered and the risk that this represented. ‘It was known, it was explained, it was recognised, it was accepted.’ The signals plan therefore had to be formed in the knowledge that they would be operating at the very limit of their resources. There was little flexibility available in the signals plan and adequate safeguards against breakdown either were not available or possible or were negated by the situation during the battle. Consequently when procedural mistakes were made the plan did not stand up to the situation.’ In conclusion he cites a prophetic quotation, ‘No signal plan [is] an isolated affair’.

British Army Wireless Set WS No. 68 circa 1944
(with credit to Pye Telecom Historical Collection)

In a addition to a background in intelligence, which initiated my original interest in the Battle of Arnhem, I have a reasonably extensive background in systems engineering. Essentially systems engineering is the discipline used to integrate total systems in order to achieve a given quantifiable level of performance, as well as maintaining, reliability (redundancy), maintainability (ease/speed of repair), availability(operability) and survivability also at given measured levels, all achieved within what is called a life cycle cost. It incorporates, the total operational environment, human operator(s), hardware subsystems, software subsystems, data transfer, normal operational, as well as alternative (casualty), modes of operation/ procedures, and most importantly the specific detailed interfaces between each of these elements. It includes the use of operational research, computer modeling/simulation, systems analysis, and various other engineering knowledge. In most final system design configurations a carefully balanced compromise of all these factors must be struck. Given that background I would like to draw an analogy to the delicate and demanding task of airborne operational planning as it evolved in World War II, and specifically in the case of Operation Market Garden.

With that perspective I would like to discuss what can be termed comprehensive negative synergy or ‘the perfect storm’. It is my personal opinion that this is precisely what resulted from the planning leading up to Operation Market Garden. Any one erroneous planning factor can impose a risk factor. However, when almost a comprehensive set of planning factors are in error, this does not constitute a balanced compromise. It is a preordained recipe for failure. My contention is that planning decisions that were made resulted in the following:

• Loss of the initial advantage of the element of surprise
• Loss of mass (Effectively down to brigade strength for 2 days, due to having to hold the DZ/LZs for the 2nd lift)
• Degradation in communications (Impact of DZ/LZ distances to objective on range of available communications equipment)
• Loss of effective command and control (Due to lack of communications)
• Severe degradation in logistics, loss of re-supply including spare wireless sets and batteries (Due to lack of communications)
• Degradation in concentration of available firepower (Due to lack of communications)
• Loss of available, albeit limited, maneuver element (Due to lack of communications)

If you have further interest in how communications and communications planning effected the outcome of the battle, please click on the home page menu bar 'Operation Market-Garden' for a detailed analysis of the planning for the operation.

Tuesday, April 19, 2011

Market Garden: Was Intelligence Responsible for the Failure?

The following is the conclusion to a research report titled; Market Garden: Was Intelligence Responsible for the Failure? (AU/AWC/NNN/2001-04), submitted by LtCol Philip G. Bradley, USAF, to the Faculty of the Air War College, Air University, Maxwell Air Force Base, Alabama, in April 2001:
Chapter 4
It is unfair to say that intelligence oversights and mistakes led to the failure of MARKET GARDEN for several reasons. First of all, it is not true that intelligence failed to paint an accurate picture of German troop strength and capability. The correct information was available along with accurate analysis. True, not all intelligence summaries agreed, but there was enough of a disagreement to warrant more investigation and certainly greater caution. Secondly, it is not true that failure to accurately assess the terrain around Arnhem caused the Allies to pick drop zones six to eight miles from the bridge. In fact, terrain was only a minor issue. Furthermore, on this issue Montgomery was inconsistent. If the German troop strength was deemed too weak to challenge ground forces, then why wasn’t it deemed too weak to challenge airlift assets?
The one instance that is clearly an intelligence failure was the lack of coordination with Dutch forces about alternate routes to Arnhem. However, this in and of itself did not cause MARKET GARDEN to fail. To the intelligence community's credit, they did accurately describe the difficult nature of the route that 30th Corps was to take.
If blame must be assigned, responsibility for MARKET GARDEN’s failure can be given to planners at the strategic and operational levels who seemed hell-bent on carrying out the operation for at least two reasons. First, there was an ever-increasing push to test airborne operations before the war came to an abrupt end. Second, Montgomery pressed the urgency of the operation in part to make sure that Britain got credit for delivering the knock out punch.
On this second point, General Miles Dempsey, commander of the British 2nd Army, provides evidence that the commander of an operation can significantly slant the perspective of the intelligence effort. According to Ryan*, Dempsey believed Dutch reports regarding German troop strength but couldn’t convince Montgomery. Dempsey did, however, send this information on to Browning’s 1st Airborne Corps. But since Montgomery didn’t endorse this information it gained no credibility. In fact according to Ryan reports of panzers in Holland were completely discounted at Montgomery’s own headquarters. In Montgomery’s own words, “We were wrong in supposing it (the 2nd S.S. Panzer Corps) could not fight effectively.”1 It might be more accurate to say that Montgomery was wrong and convinced all his subordinates to agree with him. 
*Cornelius Ryan; A Bridge Too Far

In the personal opinion of this blog author the final sentence far surpasses the term "gross English under-statement". It wasn't just Montgomery's subordinates, but peers and seniors as well. And substituting the word 'coerced' for 'convinced' would be far too mild an admonishment. If you have further interest, please click on the home page menu bar 'Operation Market-Garden' for a detailed analysis of the planning for the operation;