e-Newsletter for March 2002
Requests for Information: Please contact me if you know -
Albert J. Boyle, Jr., Squadron Bombardier, 835th.
Wilbur S. Everman, 833rd.
WWII History Programs:
Our Associate Member, Robin Sellers, is a historian at the University of Tallahassee working on an Oral History Program.
From the British contact for the 95th Bomb Group Association:
We are working on the Red Feather Club and will have an open day on Sunday the 9th of June which is the end of the week celebrating the Queen's Silver Jubilee on the Throne. We are now looking for artifacts to put on display when it is a Museum. (Bought an 8th AAF mess tin and knife, fork, and spoon for starters). I expect over time we will obtain other items. We have also two Spitfire wheels and a couple of American clothes cases you were issued with. It needs advertising to the 486ers so that they do not get thrown out by their families when they pass on. Much has gone over the years from this and other ways. None of us thought to save much after getting home after the war; we were concerned to get back to civilian life.
Many may wonder what happened to Station 174 since it was last occupied during the 486th's tour of duty. Thanks to the web, you can take a virtual tour by visiting:
Station 174 now
Make sure to click on "Aerial Photo." Then compare
Station 174 then!
The map and image of Station 174 as it looks now can be zoomed in and out, and panned N/E/W/S. You'll see that the runways have been all but removed. The perimeter tracks still exist, as do several hangars, and the 835th and 834th hardstands.
The story of RADAR (RAdio Detection And Ranging) has the same roots as that of the Atomic bomb: James Clerk Maxwell's unification of the theories of Electricity and Magnetism in 1867. This new set of physical laws began investigations into many things which lead to the development of many devices we use today to simplify our lives, and entertain ourselves. Twenty years after Maxwell published his new theory, Heinrich Herz, a German Physicist, began investigations into wireless transmissions. His experiment consisted of two loops of wire at opposite ends of his lab. Both loops each had a small gap, while only one loop had a switch and a battery attached to it. Herz would close the switch allowing current to flow through the one loop. The gap prevented a complete circuit, but as charge built up at the gap a spark would be created. According to Maxwell's theory, as the spark leapt the gap it would create electromagnetic waves that would cross the ether and induce a current in the other loop. There, too, the current induced in the loop would cause a spark at the gap, or register on a meter. His experiment was successful, and opened the way for new "wireless" communication technologies.
Herz continued his experiments and quickly discovered the induced spark was actually composed of a series of weaker sparks. After some investigation he realized that the radio waves were emitted in all directions by the first loop, and were reflecting off objects in his lab. These reflections each caused a spark at the gap of the second loop. The implications of this phenomenon were not immediately realized. It wasn't until 1900 that Nikola Tesla, a Hungarian physicist, suggested that these Herzian, or electromagnetic, waves might be useful for detecting distant metallic objects, such as ships. Unfortunately, Tesla's political attitudes caused his fall from grace and he could not win funding for his research. Four years later, in Germany, Christian Hölsmeyer was able to put together a demonstration of this technology, and most of those who witnessed it were impressed, but unwilling to fund the project. It would be another 30 years before any significant research would be conducted in this field, and a working device put to use.
In the meantime, these new Herzian waves, as they were then called, revolutionized command and control of naval and commercial shipping. Fleet commanders lost some autonomy due to the ability of shore bound admirals to monitor and direct fleet operations via radio. Navigation was also improved by this innovation. Radio beacons began to spring up around coastal regions, which emitted well defined electromagnetic beams that could be detected by ships. These beams pointed along various points around the compass, and ships detecting these beams from several stations could then determine direction and locate themselves through triangulation. In spite of the utility of this new technology, there were drawbacks.
One of the problems with radio broadcasting was its lack of discretion. Anyone with a receiver could listen in on conversations not intended for their ears if they new which frequency to tune to. This, naturally, lead to the creation of new methods of cryptology. But, even if radio transmission could be encrypted, mere changes in the amount of radio traffic could signal a change in operational status and put adversaries on alert. This new technology was a double-edged sword: it was an important tool for communications, but the elements of surprise and secrecy were also compromised. The problems of omni-directional radio transmissions became apparent during WWI.
The English and Germans used radio to their advantage, as a navigational aid, and a communications medium. However, RADAR was not among the tools available to the admirals and air marshals of either side. Even so, RADAR was given a real life demonstration during an air raid on England. In 1914 the Germans were launching bomber raids against England using dirigibles, also known as Zeppelins. During one particular raid, the British detected an incoming raid through their radio communications. Using the direction finding stations along the coast, they were able to triangulate the position of the attacking dirigibles and direct fighters on an intercept course. While not radar in the conventional sense as we've come to know it, the British would refine this type of a "multi-static" detection and ranging system in time for WWII. This system took the code name of "Chain Home," and its purpose was not immediately clear to the Germans who took a different course.
In 1934 the Germans developed their own radar system. Unlike the British who used a system of transmitters and receivers (multi-static), the German system used a single (mono-static), rotating antenna, which emitted a string of pulses then "listened" for the echoes. This system proved to be superior to the English system. The latter was inefficient, because information from the various receivers had to be transmitted to a central command for processing, then relayed to those who could respond as the situation dictated. The Chain Home system created a fan of energy 110ö wide, which demanded much power. On the other hand, the German system provided range and direction immediately. Moreover, it was compact, easily transported, and gave 360 degree coverage. As a directed beam of energy it also consumed less power. The two completely different approaches to the applications of the theory confounded the Germans. This failure to recognize the Chain Home system for what it was would lead to the failure of the Luftwaffe's bid to crush the RAF on the Western Front, which resulted in the cancellation of the invasion of England.
Radar was now an essential tool for waging war, both against ships at sea, and in the air. Radar would also prove useful in the air as the war progressed. The RAF abandoned daytime strategic bombing, due to the terrible toll on aircraft and crews. Flying only at night, navigation posed a problem, until aircraft could be fitted with radio receivers and use the direction finding stations to navigate to their targets at night. The Germans were quick to adapt and began putting radar sets aboard some of their destroyer aircraft (Bf 110 and Me 410). Used in tandem with their Freya and Wörzburg ground radar stations, specially formed night fighter units could be directed to the invading bomber stream where they could use their onboard radar systems to shoot down individual bombers. The use of radar was thus far restricted to use against air targets. Using it against targets on the ground first required some other advances.
When the Americans joined the war, the British direction finding system would prove beneficial for overcoming the European weather. Specially outfitted bombers called pathfinders had specially designed radio receivers used for direction finding. These pathfinders would ride the beams of three transmitters to the target, with the rest of the bomber stream in tow. This system, designated "Gee," had several limitations. One limitation was effective range of the transmitters. Another was a requirement to fly higher as the targets became more distant to prevent the loss of signal caused by the Earth's curvature. These affects limited the range of "Gee" to 400 miles. This system was purely a navigational system, and did not allow bombing through overcast. Once in the target area, the bombers would use H2X systems to conduct bombing when the target was obscured. "Gee" was also sensitive to German jamming, and rendered almost useless. The system was improved with the development of the "Gee-H" and "Micro-H" systems.
"Gee" systems allowed an aircrew to determine their position directly. Another radio-navigation system named "Oboe," for the aural tone similar to the musical instrument, used only two ground stations. However, the ground stations determined the position of the aircraft and radioed the information back to the bombers. This system was limited to a range of 280 miles.
"Gee" and "Oboe" allowed the bombers to navigate to the target, but did not have the accuracy to allow the bombers to drop through overcast with reasonable expectations of hitting the target. If a target was obscured by weather, haze or smoke, the aircraft couldn't drop. This was overcome by the development of the British H2S, and American H2X (" Mickey") systems. A compact airborne radar system was made feasible by the invention of the Cavity Magnetron. This device allowed for the creation of a narrow microwave radar beam, with a minimal power requirement. A rotating antenna emitted a pulse then listened for the echoes. As the antenna rotated it would illuminate a 360 degree swath of ground surface. The image was projected onto a cathode ray tube and gave a 2 dimensional representation of the ground. The contrast between land and water made coastal areas very distinctive. Contrast between variations in terrain was more difficult to identify. Metallic objects, or buildings, created strong echoes, which made metropolitan areas stand out from the surrounding country side. Buildings identified in aerial photographs were selected as radar landmarks. In spite of these innovations, visual bombing was still the most accurate method of bombing. However, the weather over Europe was seldom ideal enough for visual bombing.
Of course, there was a price to pay for carrying this equipment. The transmitter/receiver was installed in place of the ball turret reducing the armament of the liberators and forts that carried these systems. It was also heavy, since it required, not only the antenna and its housing, but the equipment and "Mickey" operator. These aircraft were also expected to carry the same bomb load as the other aircraft, and carry smoke markers as well. This caused the pilots much anguish as they flew their lumbering charges.
Of course, for every measure, there is a countermeasure. Radio communications could be disrupted by overwhelming the receivers with powerful electromagnetic noise. The same applied to radars. For those who wanted to remain invisible to enemy radar another approach was used. The British recognized the effectiveness of German radar and began loading bags with strips of aluminum. The British gave this countermeasure the code name, "Window," and the Americans would refer to it as "Chaff." Periodically, a member of the crew would eject a bag of the foil from the aircraft causing false targets in German RADAR. The foil was cut to specific lengths and widths to effectively reflect the German radar waves. Late in the war the AAF would install "Spot Jamming" equipment aboard designated aircraft to jam German fire control radars. Still, optical systems provided enough accuracy to allow the FLAK batteries to inflict damage to attacking bombers. No system was fool proof, but any protection was better than none!
RADAR's technological advancement was spurred by war, but has found civil and scientific work, too. Airports and ships at sea use RADAR to monitor traffic. Scientists have used RADAR to probe the surfaces of the moon, and neighboring planets. Satellites with onboard RADAR image the Earth's surface to monitor land usage, ice cap size, and archeology. We even use the technology to cook our food.
USAF Handbook: 1939-1945, Martin Bowman
Deflating British Radar Myths of World War II, Gregory C. Clark
Adolf Galland, David Baker
Classic Electrodynamics, Jackson
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