These yet unusual and highly efficient electron tubes could easily have been adapted to the production of SHF radio beacons, but remained unnoticed and unrecognized. The least likely tube for British consideration was the lowly “Magnetron” tubes, simple constructions which utilized axially applied magnetic fields in conjunction with a cylindrical anode (Hull, Hennelly 1921). The use of magnetic fields was predicated on an observation made when developing discharge switching tubes early in the century. It had been observed that magnetic fields finstrated and actually inhibited the approach of electrons to target anodes. By using a tangentially applied magnetic field, it was possible to actually “load” the space between cathode and anode with ever concentrated thermionic electrons. Electrons experienced side-thrusting because of the strong magnetic field applied along the tube axis. A simple adjustment in the voltage bias between cathode and anode balanced the forces on electrons in their space. Electrons then orbited the cylindrical anode but could be made never to reach the anode. The combinations of magnetic side thrust and the forward kinetic energy of electrons could produce such a high density “space charge” that the tubes began acting as capacitors.
In their initial embodiments, these tubes were useful as switching devices. They also found use as amplifiers for a variety of radio applications. Alexanderson of General Electric purloined the design for use in shortwave applications. Magnetron tubes were yet little more than curiosities, a means for providing high current alternations at shortwave broadcasting frequencies. With the experimental innovation of a split anode cylinder, new and wonderful phenomena were observed. Split along its axis, the normally sohd cylindrical anode became the unexpected site where powerful SHF alternations were suddenly being generated. When pulsed with a powerful and sudden voltage application, their SHF output was significant. Furthermore such tubes proved stable over continued periods of time. The Magnetron Tube, once a mere curiosity of electrical science, suddenly revealed itself as the probable solution to the RADAR problem. Sidestepping the Farnsworth Multipactor, the Magnetron suddenly became the prime device on which British engineers focussed all of their attentions. Magnetron development was taken into the halls of Birmingham University, a top secret project headed by Robert Watson-Watt
Arranging several magnetrons in tandem proved impractical and difficult The resultant output of these combinations was greatly enhanced by the apparent coordination of alternations set up in each single tube. This was especially evident when connective circuits were properly adjusted. The concept of joining all of the tube elements in a single vacuum envelope became a developmental path which eventually led to the great success of the RADAR project, a “multicavity” magnetron being secretly developed. A honeycomb geometry, where six adjacent cores were drilled through a thick copper disc, formed the “multicavity” space. Directly through the center of this honeycomb was drilled a central chamber, the location of an axial cathode. The entire disc was sealed, highly evacuated, and placed between the poles of a powerful permanent “horn” magnet The cathode, curiously coated with thorium and caesium, formed the axis from which powerful pulses of thermal electrons were projected toward the inner cavity walls. Constrained by this magnetic field, space charge gathered between cathode and anode with the very first application of power. These “space charge” electrons became a veritable electron cloud, rotating around its emitter cathode.
As this rotating space charge passed each face plate of the separate semicyUndrical cavities, powerful clustering action occurred. This immediately set up coordinated resonations throughout the copper disc housing. Reacting back on the dense space charge, electrons began automatically clustering and cooperating with the cavity-induced oscillations. This effectively caused electron clustres to move with a specific orbit velocity around the central cathode.
The “cyclotron” frequency. Cyclotron frequency and cavity oscillation were coordinated by external cahbration, and SHF currents were drawn out of the device through a single wire probe. Energies of these frequencies required conductive hollow piping rather than wire lines. Waveguiding used copper piping of rectangular cross-section. Multicavity Magnetrons were powered by special highpower pulsing circuits, combinations of capacitance and inductance capable of sustaining several thousand volts of significant amperages. When so operated, SHF energy effects were deadly.
This energy, pulsed through concentrating reflectors produced megawatt SHF beacons. Such beacons produced such prodigious echoes from even the smallest metallic object, that receiving circuits could mark the relative distance of any such object with greatest accuracy. First RADAR installations used Doppler effects to compare each initial transmission pulse with subsequent echoes. The difference between these two positions on a luminous display scope could accurately range small objects though yet miles away. First tests with these revolutionary High Pulse Magnetron Systems were indeed impressive. The top secret RADAR project received the strongest encouragement and recommendation from no other than Sir Winston Churchill himself. His comment that “I have just witnessed the weapon which will win the War” stimulated the necessary inspiration which drove the small group of engineers toward the unstoppable conclusion of total success.
After that approval monies and manpower appeared, and RADAR became a matter of factory line production. The RDF (Radio Direction Finding) systems were deployed everywhere along the coastlands by 1940. Regardless of time and weather, British RAF and Naval forces were on first alert Nazi Luftwaffe and U-Boats personnel were continually shocked to discover that, despite their stealth and strategic maneuvers, their British antagonists were perpetually prepared well in advance. In the war to end Hitler and Nazism, RADAR won the war. As far as Allied military was concerned, RADAR was now the wave tool of choice.
As improved Magnetron Tubes made their appearance, RADAR became a powerful standard tool for Allied aerial and maritime forces alike. Magnetron systems became compact miniatures, and highly portable. Attack planes all carried their RADAR packages. Military flights and seagoing missions could now take place at night with absolute safety, a surprising precision in shellfire being the principal repellant for enemy forces on all fronts of the War. As with every aspect of the developing radio technology, RADAR had now become permanent military hardware. Surprise attacks could never occur as long as RADAR was sweeping the air and sea. The infamous Pearl Harbor was actually the result of distrust or permission. The RADAR operator, whose screen literally ignited with the glowing evidence of 2ui unprecedented incoming air assault, was repeatedly stalled while reporting his observation. Informed that his gear was probably out of order, he was ordered to recalibrate each component, until it was too late. Such questionable incidents find their solution in simple geopolitical models and answers. It is rather obvious that oligarchic forces in North America, the NAO (North American Oligarchy), wished the acquisition of resource and territory in the South Pacific; a condition which, contrary to much public opinion today, has actually been achieved. The highly industrialized and over esteemed island empire is nothing more than an offshore manufacturing facility for nationally based financiers.
World History
