Radar and Electronic Warfare

[Mac Linehan]

Gentlemen- as an avid player of the original BTR I cannot tell you how pleased I am that Matrix is releasing Gary Grigsby's Eagle Day. Of course it has been necessary play the original and defend the Reich once again (runs just fine on XP; Mr. Grigsby did it right.)
I am indebted to Hard Sarge for supplying the 106 patches and Harley's editor. This was my first introduction to the editor (Harley - the word awesome comes to mind..) and of course the patch/editor combination gave me a completely new gaming experience. Hard Sarge commented that after playing Eagle Day, if he went back to the original, it would be a letdown. So- there is no doubt in my mind that with all of the familiar names involved-who helped to improve the original - Eagle Day will be a First Class Product.

Here are some thoughts and questions that have come to mind:

Early warning radar: Freya and Mammut are represented, but Wassermann is not. Mammut and Wassermann used the Freya 2.4 meter electronics with much larger antennas - Mammut a non rotating rectangle laying on it's long side for greater range and bearing definition (and had dipole arrays front and back to give full coverage;) Wassermann a tall very narrow antenna (for impoved range and height finding) that was capable of panoramic operation. Both were used to complement Freya. My understanding is that Freya was unable to give accurate height data; I am not sure of aircraft count. Perhaps the altitude and number of aircraft data given in the "list raids" menu of the game is representative of confirmation by various other sources (visual observers etcetera?) All this might not matter in game terms, I thought I would ask anyway.

Primary reference: Louis Brown: A Radar History of World War 2

"The deficiencies of Freya were a range shorter than the curvature of the earth imposed and a poor resolution of targets both in direction and in height, very poor in the latter. Both of these deficiencies could be reduced by increasing the antenna size while retaining the basic 2.4 meter circuitry of Freya. Increasing the number of dipoles caused a narrowing of the beam, which led to obvious improvement in the angular resolution but also concentrated the power thereby leading to an increase in range. Directional accruraacy was obtained through lobe switching.... Out of these considerations two complementary designs, Wassernan and Mammut, materialized from GEMA during the summer of 1940....

"Wasserman S (schwer or heavy) had an array of 188 dipoles in a vertical pattern mounted on a four meter diameter steel pipe 60 meters high, causing the British intellegence people to call it Chimney... This immense array of dipoles formed a thin, horizontal fan - shaped beam that could be moved up and down by altering the phase shifts in the transmission lines feeding the dipoles. This allowed a direct and rapid way of determining elevation to an accuracy of 0.75 degrees for aircraft lying between three and eight degrees; lobe switching gave azimuthal accuracy of 0.25degrees. At 100 km this localized the target in a box shaped region 1200 m high; 300 m long and 435 m wide for planes above 5200m. Aircraft 8000m high could be detected at 210 km, and very high fliers at 300 km. Mechanical rotation about the vertical axis allowed a 360 degree field of observation."

"The exceptional long range accuracy of Wassermann was used to determine the positions of individual forations of attackers, a process that took minutes of valuable time. The designers asumed that they would have to contend with multiple formations, and Mammut allowed thse to be tracked rapidly and accurately in the horizontal plane with no hight information. Mammut had 192 dipoles arranged in a fixed array 16 meters high and 30 meters wide mounted on four vertical steel beams. It's appearance secured for it the British intellegence nameof Hoarding (in American, Bill - Board.) It's wide array produced a narrow, vertical fan - shaped beam that could be pointed in a horizontal direction by altering the phase shifts in the transmission lines feeding the dipoles, just as done for Wassermann in the other direction. This allowed 100 degrees of coverage; lobe switching yielded a directional accuracy of 0.5 degrees."

"These two basic designs formed most of the luftwaffe's early warning throughout the war. Together they proved capable of dissecting the immense numbers of bombers that were to attack Germany as the air war proceeded, numbers which would have saturated Chain Home (50 meter; Great Britain.) Although these radars operated on a wavelength one - fifth that of CH, they shared it's unsuspected characteristic of being difficult to put out of action. The tall, spindly towers proved resistant to explosives, and the electronics and operation room was in a bunker. Later they proved vulnerable to rocket firing aircraft." pgs 280 - 281

Next:

German Night Fighter defense - the Himmelbett (or Kammhuber) line - was dependent on geographic boxes, each containing a Freya for early warning and one or two Giant Wurtzbergs (50 or 60 centimeter) to track bomber and night fighter for a Gound Control Intercept. Flak was also highly dependent on Wurtzburg for blind firing. Is this system represented abstractly? - perhaps within the scale of the game it is immaterial.

Airborne radars - will a wider range of equipments be represented (presuming that there is a relevance and impact on game play.)

I am not a radar specialist ( to my understanding there is a member of the forum who is,) just an enthusuastic amateur. I suspect many of the Matrix team as well as members of this forum are very well read in this particular subject. Well that's it for now. Thank you for you patience,

regards Mac