Boat Experiment (Part of Philadelphia Experiment Mock Up)
(Actually done in 2006, not 2007)
Hear John Briefly Discuss this on Truth Quest - Melodee and Dr E Karlstrom - 14 Aug 2009
from the team of
Dr. John Hutchison & Dr. Ronnie Milione
Allegedly, in the fall of 1943 a U.S. Navy destroyer was made invisible and teleported from Philadelphia, Pennsylvania, to Norfolk, Virginia,
in an incident known as the Philadelphia Experiment.
"A Highly complicated Piece of Equipment Had to be constructed in order to Unfreeze those who became "True Froze" or "Deep Freeze" subjects. Usually a "Deep Freeze" Man goes Mad, Stark Raving, Gibbering, Running MAD, if His "freeze" is for More than a Day in our time.
I speak of TIME for DEEP "Frozen Men" are Not aware of Time as We know it. The are Like Semi-comatose person, who Live, breathe, Look & feel but still are unaware of So Utterly Many things as to constitute a "Nether World" to them. A Man in an ordinary common Freeze is aware of Time, sometimes acutely so. Yet They are Never aware of Time precisely as you and I are aware of it. The First "Deep Freeze" As I said took 6 months to Rectify. It also took over 5 Million Dollars worth of Electronic equipment & a Special Ship Berth."
VISIT ALSO
Dr. John Hutchison & Dr. Ronnie Milione Navy Radar Systems
PLEASE VISIT THE FOLLOWING WEB SITE FOR MORE INFORMATION:
http://www.global-communication-networks.com/ - Dr. Ronnie Milione
All Rights Reserved
Copyrighted by Dr. Ronnie Milione & Dr. John Hutchison
Introduction
USS Eldridge (DE-173), 1943-1951
USS Eldridge, a 1240-ton Cannon class destroyer escort built at Newark, New Jersey, was commissioned in August 1943. She was employed on escort duties in the Atlantic until May 1945, when she departed for service in the Pacific. Eldridge was decommissioned in July 1946 and placed in the Reserve Fleet. In January 1951, she was transferred to the Greek Navy, in which she served as Leon into the 1990s.
Let's Begin.....
Project Rainbow was allegedly an experiment conducted upon a small destroyer escort ship during World War II, both in the Philadelphia Naval Yard and at sea; the goal was to make that ship invisible to enemy detection. The accounts vary as to whether the original idea was to achieve invisibility to enemy radar or whether the prize sought after was more profound: optical invisibility. Either way, it is commonly believed that the mechanism involved was the generation of an incredibly intense magnetic field around the ship, which would cause refraction or bending of light or radar waves around the ship, much like a mirage created by heated air over a road on a summer day. The legend goes on to say that the experiment was a complete success... except that the ship actually disappeared physically for a time, and then returned. They wanted to "cloak" the ship from view, but they got de-materialization and teleportation instead..
It has been claimed that the Philadelphia Experiment was partly an investigation into how Albert Einstein's "Unified Field Theory for Gravitation and Electricity" might be used to advantage in the development of electronic camouflage for ships at sea. Einstein allegedly published his Unified Theory around 1925-27 in German, in a Prussian scientific journal, but it was later withdrawn as incomplete. This research was aimed at using intense electromagnetic fields to mask a ship from incoming projectiles, mainly torpedoes. This was later extended to include a study of creating radar invisibility by a similar field in the air rather than in the water.
The story begins in June of 1943, with the U.S.S. Eldridge, DE (Destroyer Escort) 173, being fitted with tons of experimental electronic equipment. This included, according to one source, two massive generators of 75 KVA each, mounted where the forward gun turret would have been, distributing their power through four magnetic coils mounted on the deck. Three RF transmitters (2 megawatt CW each, mounted on the deck), three thousand '6L6' power amplifier tubes (used to drive the field coils of the two generators), special synchronizing and modulation circuits, and a host of other specialized hardware were employed to generate massive electromagnetic fields which, when properly configured, would be able to bend light and radio waves around the ship, thus making it invisible to enemy observers.
The experiment, said to have taken place at the Philadelphia Naval Yard and also at sea, took place on at least one occasion while in full view of the Merchant Marine ship S.S. Andrew Furuseth, and other observation ships. The Andrew Furuseth becomes significant because one of its crewmen is the source of most of the original material making up the PX legend. Carlos Allende, a.k.a. Carl Allen, wrote a series of strange letters to one Dr. Morris K. Jessup in the 1950's in which he described what he claims to have witnessed: at least one of the several phases of the Philadelphia Experiment.
At 0900 hours, on July 22nd, 1943, so the story goes, the power to the generators was turned on, and the massive electromagnetic fields started to build up. A greenish fog was seen to slowly envelop the ship, concealing it from view. Then the fog itself is said to have disappeared, taking the Eldridge with it, leaving only undisturbed water where the ship had been anchored only moments before.
The elite officers of the Navy and scientists involved gazed in awe at their greatest achievement: the ship and crew were not only radar invisible but invisible to the eye as well! Everything worked as planned, and about fifteen minutes later they ordered the men to shut down the generators. The greenish fog slowly reappeared, and the Eldridge began to dematerialize as the fog subsided, but it was evident to all that something had gone wrong.
When boarded by personnel from shore, the crew above deck were found to be disoriented and nauseous. The Navy removed the crew, and shortly after obtained another. In the end, the Navy decided that they only wanted radar invisibility, and the equipment was altered.
On the 28th of October in 1943, at 17:15, the final test on the Eldridge was performed. The electromagnetic field generators were turned on again, and the Eldridge became near-invisible; only a faint outline of the hull remained visible in the water. Everything was fine for the first few seconds, and then, in a blinding blue flash, the ship completely vanished. Within seconds it reappeared miles away, in Norfolk, Virginia, and was seen for several minutes. The Eldridge then disappeared from Norfolk as mysteriously as it had arrived, and reappeared back in Philadelphia Naval Yard. This time most of the sailors were violently sick. Some of the crew were simply "missing" never to return. Some went crazy, but, strangest of all, five men were fused to the metal in the ship's structure.
The men that survived were never the same again. Those that lived were discharged as "mentally unfit" for duty, regardless of their true condition.
So, what had begun as an experiment in electronic camouflage, ended up as an accidental teleportation of an entire ship and crew, to a distant location and back again, all in a matter of minutes!
Although the above may seem fantastic, one must remember, that in the 1940’s the atomic bomb was also being invented.
More information.......
The experiment was an attempt to move equipment and personnel through time and space using a Naval warship known as the USS Eldridge (DE-173), a destroyer escort. On August 15, 1943, a total of 181 men (176 sailors and 5 civilian scientists of which I was one of) were on board the Eldridge and along with one observation ship set out to sea for an experiment of which was never before attempted. Using technology that had already been proven successful on a smaller scale, the human factor was for the first time included within the scope of the experiments, whereas before only inanimate objects were used. We did, however, experiment with small animals during a dry run conducted on the 12th of August, 1943, which had horrifying results. There were three different agendas', which were:
1. a scientific agenda, which was to explore the time/space continuum for scientific discovery;
2. a military agenda, which since we were at war (World War II) the military wanted this technology for warring purposes; and lastly,
3. there was an extraterrestrial agenda, which was to map out the earth's planetary magnetic grid for interdimensional travel.
There was a CORE agenda, which was secretly held close at hand by those behind the scenes. I identify them as "those in the know", and their agenda was to REWRITE HISTORY!
The origin of the NAVY'S Top Secret project in 1943 when radar invisibility was being researched aboard the USS Eldridge. As the Eldridge was stationed at the Philadelphia Navy Yard, the events concerning the ship have commonly been referred to as the "Philadelphia Experiment". Having been the subject of different books and a reality show, only a quick synopsis will be given here.* The Philadelphia Experiment was known as the Rainbow Project to those who manned and operated it. It was designed as a top secret project that would help end World War II. The forerunner of today's stealth technology, the Rainbow Project was experimenting with a technique to make a ship invisible to enemy radar. This was done by creating an "electromagnetic bottle" which actually diverted radar waves around the ship. An "electromagnetic bottle" changes the entire electromagnetic field of a specific area - in this case, the field encompassing the USS Eldridge. While the objective was to simply make the ship undetectable by radar, it had a totally unexpected and drastic side effect. It made the ship invisible to the naked eye and removed it from the space-time continuum. The ship suddenly reappeared in Norfolk, Virginia, hundreds of miles away. The project was a success from a material standpoint, but it was a drastic catastrophe to the people involved. While the USS Eldridge "moved" from the Philadelphia Naval Yard to Norfolk and back again, the crew found themselves in complete disorientation. They had left the physical universe and had no familiar surrounding to relate to. Upon their return to the Philadelphia Navy Yard, some were planted into the bulkheads of the ship itself. Those who survived were in a mental state of disorientation and absolute horror. The crew were subsequently discharged as "mentally unfit" after having spent considerable time in rehabilitation. The status of "mentally unfit" made it very convenient for their stories to be discredited. This put the Rainbow Project at a standstill. Although a major breakthrough had occurred, there was no certainty that human beings could survive further experimentation. It was too risky. Dr. John von Neumann, who headed the project, was now summoned to work on the Manhattan Project. This concerned the making of the atom bomb, which became the weapon of choice for ending World War II. Although it is not well known, vast research that began with the Rainbow Project was resumed in the late 1940's. It continued on, culminating with a hole being ripped through space-time at Montauk in 1983.
The goal of this revisited experiment to be conducted by the fame John Hutchison and Ronnie Milione is to give you a general understanding of the research and events subsequent to the Philadelphia Experiment to be revisited.
The Real Historic Details
USS Eldridge (DE-173), 1943-1951
In 1912, a mathematician named David Hilbert developed several different methods of new math. One of these was known as "Hilbert Space." With this he developed equations for multiple realities and multiple spaces. He met Dr. John von Neumann in 1926 and shared his information. Von Neumann took a lot of the systems he learned from Hilbert and ran with it. According to Einstein, von Neumann was the most brilliant of mathematicians. He had an uncanny ability to take abstract theoretical concepts in math and apply them to physical situations. Von Neumann developed all kinds of new systems and math. A Dr. Levinson had come along and developed the "Levinson Time Equations." He published three books, which are now very obscure and almost impossible to find. An associate of mine did dig up two of them at Princeton's Institute for Advanced Study. All of this work was to serve as a background for the invisibility project which would apply the theoretical principles to a large hard object. Serious research into the subject of invisibility began in earnest in the early 1930's at the University of Chicago. Dr. John Hutchinson Sr. served as Dean at this particular time and was privy to the work of Dr. Kurtenhauer, an Austrian physicist then at the University.
They were later joined by Nikola Tesla. Together, they studied the nature of relativity and invisibility. In 1933, the Institute for Advanced Study was formed at Princeton University. This included Albert Einstein and John von Neumann, a brilliant mathematician and scientist. The invisibility project was transferred to Princeton shortly thereafter. In 1936, the project was expanded and Tesla was made the director of the group. With Tesla on board, partial invisibility was achieved before the end of the year. Research went on to 1940 when a full test was done in the Brooklyn Naval Yard. It was a small test, with no one on board the vehicle. The ship used was powered by generators from other ships, connected by cables. Another scientist, T. Townsend Brown, became involved at this point. He was known for his practical ability to apply theoretical physics. Brown had a background in gravity and magnetic mines. He had developed counter measures to the mines with a technique known as degaussing. This would trip the mines at a safe distance.
There was a big brain drain on Europe in the 1930's. Many Jewish and Nazi scientists were smuggled into the country. Much of this influx has been attributed to A. Duncan Cameron Sr. Although we know he had extensive connections, his exact relationship to intelligence circles is still a mystery. By 1941, Tesla had full confidence of the powers that be (FDR). A ship was procured on his behalf, and he had coils wrapped around the entire ship. His famous Tesla coils were also employed on the ship. However, he grew wary because as the project developed, he knew there would be problems with personnel. Perhaps he knew this due to his ability to fully visualize his inventions in his mind. In any case, Tesla knew that the mental state and bodies of the crew would be affected severely. He wanted more time to perfect the experiment. Von Neumann disagreed with this vehemently at the time and the two never got along. Von Neumann was a brilliant scientist but did not embrace metaphysics for its own sake. Metaphysics was old hat to Tesla, and he had built a successful legacy of inventions based upon his unique prescience. Part of what made his views so controversial was that during his experiments in Colorado Springs, circa 1900, he said that off planet intelligence had contacted him via consistent signal messages when Mars approached. This also occurred in 1926 when he had radio towers erected in the Waldorf Astoria and at his New York city lab. He claimed to receive information that he'd lose people if things were not changed. He needed time to design new equipment. Tesla's requests for more time were not heeded.
The government had a war to win and additional time was not granted. Tesla went through the motions but secretly sabotaged the operation in March 1942. He was either fired or quit. He is supposed to have died in 1943, but there is arguable evidence to suggest he was wicked off to England. A look-alike derelict is supposed to have been put in his place for the funeral. He was cremated the day after his body was found which was not in keeping with the tradition of his family's orthodox faith. Whether or not he died is controversial. That secret papers were removed from his safe has never been in question. Von Neumann was named director of the project. He did a study and determined that two huge generators would be required for the experiment. The keel for the USS Eldridge was laid in July 1942. Tests were done at dry dock. Then, in late '42, von Neumann decided that the experiment could be fatal to people, just as Tesla had suggested. Ironically, he still got upset at the mention of Tesla's name. He decided a third generator would do the trick. He had time to build one but never got the third one to synchronize with the other two. It never worked because the gear box was incompatible. The experiment went out of control and a Navy technician was zapped, went comatose for four months and left the project. They pulled out the third generator. Von Neumann wasn't satisfied, but his superiors weren't going to wait any longer.
In July 20, 1943, they decided it was ready and made tests. Duncan Cameron Jr. and his brother, Edward, were in the control room to operate it. The ship was no longer at anchor and orders came by radio to turn it on. Fifteen minutes of invisibility ensued. There were immediate problems with people. They got sick, some experiencing nausea. There were also mental illnesses and psychological disorientation. They needed more time, but the final deadline was given for August 12th, 1943. The orders came from the Chief of Naval Operations, and he said he was only concerned with the war. Trying to avoid damage to individuals involved, von Neumann tried to modify the equipment so that only radar invisibility would be achieved, not literal sight invisibility. Six days before the final test on the Eldridge. However, for three to six minutes, things looked good. It appeared it might work without any devastating effects. They could see the outline of the ship - everything was gone. There were problems. The principal radio mast and the transmitter were broken. People were jammed in the bulkheads. Others were walking around in an insane state. Duncan and Edward Cameron did not suffer the same trauma as their shipmates. They had been shielded in the generator room which was surrounded by steel bulkheads. The steel acted as a shield to the RF energy. As they witnessed things falling apart, they tried to shut off the generator and transceivers but were unsuccessful.
Ships Log - Notice the Date!
U.S.S. Eldridge, July 25, 1943
U.S.S. Eldridge at sea in 1944
U.S.S. Eldridge at sea in 1944
U.S.S. Eldridge at sea April 25th, 1944
U.S.S. Eldridge at sea in 1944
U.S.S. Eldridge at sea in 1944
U.S.S. Eldridge at sea April 25th, 1944
U.S.S. Eldridge at sea April 25th, 1944
SHIPYARDS
Philadelphia Naval Yard, November 1947
Newport News Shipyard, October 17th, 1944
Norfolk Naval Yard - Helena Annex, December 12th, 1944
Norfolk Naval Yard - Portsmouth, December 12th, 1944
Let's talk about RADAR
 Figure 1: radar principle | The electronics principle on which radar operates is very similar to the principle of sound-wave reflection. If you shout in the direction of a sound-reflecting object (like a rocky canyon or cave), you will hear an echo. If you know the speed of sound in air, you can then estimate the distance and general direction of the object. The time required for a return echo can be roughly converted to distance if the speed of sound is known. |
Radar uses electromagnetic energy pulses in much the same way, as shown in figure 1. The radio-frequency (rf) energy is transmitted to and reflects from the reflecting object. A small portion of the energy is reflected and returns to the radar set. This returned energy is called an ECHO, just as it is in sound terminology. Radar sets use the echo to determine the direction and distance of the reflecting object.
Radar is an acronym for
Radio (Aim) Detecting And Ranging
The word „Aim” was inserted during the time of the World War II approximately. Later, it was left out again since RADAR doesn't concern only aims, however.
The basic principle of operation of primary radar is very easy to understand, however, the theory can be quite complex. An understanding of the theory is essential to correctly specify and operate primary radar systems. Implementation and operation of primary radars systems involves a wide range of disciplines including building works, heavy mechanical and electrical engineering, high power microwave engineering and advanced high speed signal and data processing techniques. Some laws of nature have a greater importance here, though.
Radar measurement of range, or distance, is made possible because of the properties of radiated electromagnetic energy.
- This energy normally travels through space in a straight line, at a constant speed, and will vary only slightly because of atmospheric and weather conditions. (The effects atmosphere and weather have on this energy will be discussed later; however, for this discussion on determining range, these effects will be temporarily ignored.)
- Electromagnetic energy travels through air at approximately the speed of light,
- 300,000 kilometers per second or
- 186,000 statute miles per second or
- 162,000 nautical miles per second.
- Reflection of electromagnetic waves
The electromagnetic waves waves are reflected if they meet an electrically leading surface. If this reflected wave is registered again at the place of the origin, this is a proof of this that an obstacle is in the propagation direction.
Radar Basic Principles
The following figure shows the operating principle of a primary radar. The radar antenna illuminates the target with a microwave signal, which is then reflected and picked up by a receiving device. The electrical signal delivered by the receiving antenna is called echo or return. The radar signal is generated by a powerful transmitter and received by a highly sensitive receiver.
Figure 1: Block diagram of a primary radar
All targets produce a diffuse reflection i.e. it is reflected in a wide number of directions. The reflected signal is also called scattering. Backscatter is the term given to reflections in the opposite direction to the incident rays.
Radar signals can be displayed on the traditional plan position indicator (PPI) or other more advanced radar display systems. A PPI has a rotating vector with the radar at the origin which indicates the pointing direction of the antenna and hence the bearing of targets.
The Radar Equation
The radar equation represents the physical dependences of the transmit power, the wave propagation up to the receiving of the echo-signals. Furthermore can be assessed the performance of radar sets with the radar equation.
Argumentation/Derivation
At first we assume, that electromagnetic waves can propagate with ideal conditions without disturbing influences.
If high-frequency energy is emitted by an isotropic radiator, than the energy propagate evenly to all directions. Areas of same power density therefore form spheres ( A= 4 π R² ) around the radiator. At incremented spheric radius the same value of energy spreads out around on an incremented spherical surface. That means: the power density on an assumed area becomes lower with an increasing distance of the radiator.
Figure 1: nondirectional power density
So we get the formula to calculate the Nondirectional Power Density Su
| PS = transmitted power [W] SU = nondirectional power density R1 = Range Antenna - Target [m] | (1) |
If the irradiation is limited on a spherical segment (at constant transmit power), then results an increase of the power density in direction of the radiation. This effect is called antenna gain. This gain is made by directional irradiation of the power. For the directional power density apply:
Sg = directional power density G = antenna gain | (2) |
Of course in the reality radar antennas aren't „partially radiating” isotropic radiators. Radar antennas have to have a small beam width and an antenna gain up to 30 or 40 dB. (e.g. parabolic dish antenna or phased array antenna).
The target detection isn't only dependent on the power density at the target position. In addition of this it depends by the reduction how much is back reflected actually in direction of the radar equipment. To be able to determine the utilizable reflected power, the value of the radar cross section σ is needed. This difficultly comprehensible quantity is dependent on several factors. It is that way plausibly at first, a bigger area reflects more power than a little area. That means:
A Jumbo jet offers more radar cross section than a sporting aircraft at same flight situation. Beyond this the re-reflecting area depends on design, surface composition and the using materials.
This is said summarized till now: At the final destination the reflected power Pr arises from the power density Su, the antenna gain G and the very variable radar cross section σ:
| ||||||||
Simplified a target can be regarded as a radiator in turn due to the reflected power. The reflected power Pr then becomes the emitted power.
Since there are the same conditions as on the way there on the way back of the echos yields himself for the power density at the receive place Se:
Figure 2: Connection between
formula 3 and 4
| Se = power density at receive place Pr = reflected power [W] R2 = range antenna - target [m] | (4) |
At the radar antenna the received power is dependent on the power density at the receive place PE and the effective antenna area AW .
| PE = power density at the receive place [W] AW = effective antenna area [m²] | (5) |
The effective antenna area arises from the fact that an antenna doesn't work loss-freely i.e. the geometric measurements are available not quite as a receive area. As a rule, the effect of an antenna is smaller than these have geometric measurements suspected around the factor 0.6 to 0.7 (Factor Ka).
Applies to the effective antenna area:
| AW = effective antenna area [m²] A = geometric antenna area [m²] Ka = Factor | (6) |
For the power at the receive place PE arises therefore:
  | (7) |
(8) |
The way there and way back was looked at separately at the argumentation till now. With the next step both ways being summarized: Since R2 (Target - Antenna) is the distance R1 (Antenna - Target) at once, this is taken into account now
  | (9) |
Another given equation (however, this one shall not be derived in this place) puts the antenna gain G in connection with the used wavelength λ.
| (10) |
This is convert to the antenna area A and put into the upper equation. After the simplification it yields:
| (11) |
After the converting to the range R the classic form results for the radar equation:
  | (12) |
All quantities which have influence on the wave propagation of the radar signals were taken into account at this radar equation. Beyond this the dependences of the sizes were illustrated and summarized in the classic radar equation at least.
Until after this theoretical attempt can be used the radar equation very well also in the practice e.g. to determine the efficiency of radar sets. The form of the classic radar equation isn't, however, suitable for these extended considerations yet. Some further considerations are necessary.
Obtained on a given radar equipment most sizes (Ps, G , λ) can be regarded as constant since they are only in very little ranges variable parameters. Against this the radar cross section represents a quantity to be described heavily and therefore 1 m² is assumed as a practical oriented value mostly.
  | (13) |
Under this condition that value of the received power PE is interesting, which in the radar receiver causes an even still visible signal. This received power is called PE min. Smaller received powers aren't usable since they would lost in the noise of the receiver. The occurred into the radar equation received power PE min causes that with the equation the theoretically maximum range Rmax can be calculated now.
An application of this radar equation is the determination of the performance of radar units to compare each other.
Influences on the maximum range of a radar unit
All considerations in connection with the radar equation were made under the prerequisite till now that the electromagnetic waves can propagate under ideal conditions without disturbing influences. In the practice a number of losses appears, though. These cannot remain unconsidered since they partly reduce the effectiveness of a radar unit considerably.
To this, at first the radar equation is extended by the loss factor Lges.
  | (14) |
This factor summarizes the following listed kinds of losses:
- L D = internal attenuation factors of the radar unit on the transmitting path and the receive path
- L f = fluctuation losses during the reflection
- L Atm = atmospheric losses during the propagation of the electromagnetic waves in direction of the target (and the way back)
Piece of internal losses arise in the main thing at high frequency components, like waveguides, filters but also by a radome. Obtained on a given radar unit this kind of loss is relatively constant and also well measurable in it's value.
As permanent influence, still has to be called the atmospheric attenuation and reflections at the earth's surface.
Influence of the earth's surface
An extended, lesser-used form of the radar equation considers additional factors, like the influence of the Earth's surface and does not continue to classify receiver sensitivity and the atmospheric absorption. 
In this formula, in addition to the already well-known quantities:
| Kα= | Dissipation factor in place of Lges. | Az= | effective reflection surface in place of σ |
| Ti= | Pulse length | K= | Boltzmann's constant |
| T0= | absolute Temperature in °K | nR= | Noise figure of the receiver |
| d= | Clarity factor of the display terminal | γ= | Reflected beam angle |
| δR= | Break-even factor | Re= | Distance of the absorbing medium |
The factor with the trigonometric functions represents the influence of the Earth's surface. The earth plane immediately surrounding a radar antenna has a significant impact on the vertical polar diagram. Radar Reflections from Flat Ground
| By the combination of the direct with the reflected echo, the transmitting and receiving patterns of the antenna change. This influence is substantial in the VHF range and decreases with increasing frequency. For the detection of targets at low heights, a reflection at the Earth's surface is necessary. This is possible only if the ripples of the area within the first Fresnel zone do not exceed the value 0.01 R (i.e.: Within a radius of 1000 m no obstacle may be larger than 1 m!). |  |
Specialised Radars at lower ( VHF-) frequency band make use of the reflections at the Earth's surface and lobing to maximise cover at low levels. At higher frequencies these reflections are more disturbing. The following picture shows the lobe structure caused by ground reflections. Normally this is highly undesirable as it introduces intermittent cover as aircraft fly through the lobes. The technique has been used in ATC ground mounted radars to extend the range but is only successful at low frequencies where the broad lobe structure permits adequate cover at higher elevations.
  | Free space vertical pattern diagram |
| Effect of ground reflections | |
| Gray, my dear friend, is every theory: here it is the idealized cosecant squared- diagram! |
Raising the height of the antenna has the effect of making the lobbing pattern finer. A fine grained lobing structure is often filled in by irregularities in the ground plane. Specifically, if the ground plane deviates from a flat surface then the reinforcement and destruction pattern resulting from the ground reflections breaks down. Avoidance of lobe effects is one of the prime considerations when selecting a radar location and the height of the antenna.
Distance-determination
The distance is determined from the running time of the high-frequency transmitted signal and the propagation speed C0. The actual range of a target from the radar is known as slant range. Slant range is the line of sight distance between the radar and the object illuminated while ground range is the horizontal distance between the emitter and its target and its calculation requires knowledge of the target's elevation. At this this one, however, to and way back must taken into account. Therefore the following formula arises for the slant range:
| t = measured time [s] R = slant range [m] |
The Distances are expressed in kilometers or nautical miles.
Derivation of the equation
Range is the distance from the radar site to the target measured along the line of sight.
v = speed |
Figure 1: principle of radar | ||||||||||
| The factor of two in the formula comes from the observation that the radar pulse must travel to the target and back before detection, or twice the range.
|
| Where C0= 3 x 108 m/s, is the speed of light at which all electromagnetic waves propagate. |
If the respective running time t is known then can be calculated the distance R with help of this equation between a target and the radar set.
To distinguish a moving target of a fixed object with help of the Doppler frequency, at least two periods of the deflection must be compared with each other.
Since the Doppler- frequency (few Hertz) is small relatively to the transmitted frequency (much Mega-Hertz), therefore a phase comparison is more easily to carry out than a direct frequency comparison technically.
The storage of a deflection is carried out in suitable memory media, in the past in special analogous vacuum memory tubes, later also with a chain of condensers (distance: digital, signal: analogous) and today only in digital memory cells.
Figure 1: functional block circuit diagram of a coherent receiver
Well, a fixed target suppression happens by the phase comparison of the echoes received by several pulse periods (pulse- pair processing). If the phase relationship is always equal, then there isn't any phase difference and the target will be suppressed. If the target has moved, the phase difference is unequally zero and the target will be shown on the screen.
To get the necessary frequency-reference for the phase-detector, a high correct coherent oscillator (called: „Coho”) is synchronized with the down converted on the IF- frequency transmitting pulse.
The echo signal of a moving target at the output of the phase-detector changes it's value and also the polarity in every pulse period. A fixed cluttersignal will keep it's value and polarity in every pulse period.
A pulse period is stored in a memory and than it is subtracted from the following period. On this way the moving target produce an output signal and the fixed clutter don't do this.
Figure 2:Oscillogram of an output signal of a phase-detector
TRANSMITTER REVIEW
The radar transmitter produces the short duration high-power rf pulses of energy that are radiated into space by the antenna. The radar transmitter is required to have the following technical and operating characteristics:
- The transmitter must have the ability to generate the required mean RF power and the required peak power
- The transmitter must have a suitable RF bandwidth.
- The transmitter must have a high RF stability to meet signal processing requirements
- The transmitter must be easily modulated to meet waveform design requirements.
- The transmitter must be efficient, reliable and easy to maintain and the life expectancy and cost of the output device must be acceptable.
The radar transmitter is designed around the selected output device and most of the transmitter chapter is devoted to describing output devices therefore:
- One main type of transmitters is the keyed-oscillator type. In this transmitter one stage or tube, usually a magnetron, produces the rf pulse. The oscillator tube is keyed by a high-power dc pulse of energy generated by a separate unit called the modulator. This transmitting system is called POT (Power Oscillator Transmitter). Radar units fitted with an POT are either non-coherent or pseudo-coherent.
- Power-Amplifier-Transmitters (PAT) are used in many recently developed radar sets. In this system the transmitting pulse is caused with a small performance in a waveform generator. It is taken to the necessary power with an amplifier followingly (Amplitron, klystron or Solid-State-Amplifier). Radar units fitted with an PAT are fully coherent in the majority of cases.
- A special case of the PAT is the active antenna.
- Even every antenna element
- or every antenna-group
- A special case of the PAT is the active antenna.
Pictured is a keyed oscillator transmitter of the radar unit.
The picture shows the typical transmitter system that uses a magnetron oscillator and a waveguide transmission line. The magnetron at the middle of the figure is connected to the waveguide by a coaxial connector. High-power magnetrons, however, are usually coupled directly to the waveguide. Beside the magnetron with its magnets you can see the modulator with its thyratron. The impulse-transformer and the pulse-forming network with the charging diode and the high-voltage transformer are in the lower bay of this rack.
Pseudo-coherent Radar Review
Figure 1: The principle of a pseudo-coherent radar.
A requirement for any Doppler radar is coherence; that is, some definite phase relationship must exist between the transmitted frequency and the reference frequency, which is used to detect the Doppler shift of the receiver signal. Moving objects are detected by the phase difference between the target signal and background clutter and noise components. Phase detection of this type relies on coherence between the transmitter frequency and the receiver reference frequency.
If the transmitter output stage is a self oscillating device, the pulse to pulse phase is random on transmission. In coherent detection, a stable cw reference oscillator signal, which is locked in phase with the transmitter during each transmitted pulse, is mixed with the echo signal to produce a beat or difference signal. Since the reference oscillator and the transmitter are locked in phase, the echoes are effectively compared with the transmitter in frequency and phase. This phase reference must be maintained from the transmitted pulse to the return pulse picked up by the receiver.
Pseudo-coherent Radar sets are sometimes called: „coherent-on-receive”
Duplexer
The duplexer alternately switches the antenna between the transmitter and receiver so that only one antenna need be used. This switching is necessary because the high-power pulses of the transmitter would destroy the receiver if energy were allowed to enter the receiver.
Mixer Stage
The function of the mixer stage is to convert the received rf energy to a lower, intermediate frequency (IF) that is easier to amplify and manipulate electronically. The intermediate frequency is usually 30 or 60 megahertz. It is obtained by heterodyning the received signal with a local-oscillator signal in the mixer stage. The mixer stage converts the received signal to the lower IF signal without distorting the data on the received signal.
IF-Amplifier
After conversion to the intermediate frequency, the signal is amplified in several IF-amplifier stages. Most of the gain of the receiver is developed in the IF-amplifier stages. The overall bandwidth of the receiver is often determined by the bandwidth of the IF-stages.
Automatic Frequency Control
As in all superheterodyne receivers, controlling the frequency of the local oscillator keeps the receiver tuned. Since this tuning is critical, some form of automatic frequency control (afc) is essential to avoid constant manual tuning. Automatic frequency control circuits mix an attenuated portion of the transmitted signal with the local oscillator signal to form an IF signal. This signal is applied to a frequency-sensitive discriminator that produces an output voltage proportional in amplitude and polarity to any change in IF-frequency. If the IF signal is at the discriminator center frequency, no discriminator output occurs. The center frequency of the discriminator is essentially a reference frequency for the IF-signal.
The output of the discriminator provides a control voltage to maintain the local oscillator at the correct frequency.
Stable Local Oscillator
As the receiver is normally a super heterodyne, a stable local oscillator known as the StaLO down converts the signal to intermediate frequency.
Most radar receivers use a 30 or 60 megahertz intermediate frequency. The IF is produced by mixing a local oscillator signal with the incoming signal. The local oscillator is, therefore, essential to efficient operation and must be both tunable and very stable. For example, if the local oscillator frequency is 3,000 megahertz, a frequency change of 0.1 percent will produce a frequency shift of 3 megahertz. This is equal to the bandwidth of most receivers and would greatly decrease receiver gain.
The power output requirement for most local oscillators is small (20 to 50 milliwatts) because most receivers use crystal mixers that require very little power.
The local oscillator output frequency must be tunable over a range of several megahertz in the 4,000-megahertz region. The local oscillator must compensate for any changes in the transmitted frequency and maintain a constant 30 or 60 megahertz difference between the oscillator and the transmitter frequency. A local oscillator that can be tuned by varying the applied voltage is most desirable.
Phase-sensitive Detector
The IF-signal is passed to a phase sensitive detector (PSD) which converts the signal to base band, while faithfully retaining the full phase and quadrature information of the Doppler signal. This means, the phase-sensitive detector produces a video signal. The amplitude of the video signal is determined by the phase difference between the coho reference signal and the IF echo signals. This phase difference is the same as that between the actual transmitted pulse and its echo. The resultant video signal may be either positive or negative.
Signal Processor
The signal processor is that part of the system which separates targets from clutter on the basis of Doppler content and amplitude characteristics.
Directional Coupler
The directional coupler provides a sample of the transmitter output on every pulse. This signal adjusts the STALO frequency via the AFC but more importantly, it adjusts the phase of the COHO, locking it to the phase reference from the magnetron. The phase synchronization of the COHO by means of a sample of the magnetron output is mandatory because there is no phase correlation between two successive RF pulses of the magnetron.
Mixer Stage
The function of this mixer stage is to convert the sample of the transmitter output to the intermediate frequency. This coho lock pulse synchronize the coho to a fixed phase relationship with the transmitted frequency at each transmitted pulse.
Coherent Oscillator
The second local oscillator known as the coherent oscillator (COHO) enables the down conversion process into the phase sensitive detector, whilst maintaining an accurate phase reference. The coho lock pulse is originated by the transmitted pulse. It is used to synchronize the coho to a fixed phase relationship with the transmitted frequency at each transmitted pulse.
The COHO takes over the phase of the transmitter tube and provides it to the receiver part of the system. This is the reason why the pseudo-coherent radar is also called „coherent on receive”.
Modulator
The oscillator tube of the transmitter is keyed by a high-power dc pulse of energy generated by this separate unit called the modulator.
Disadvantages of the pseudo-coherent radar
The disadvantages of the pseudo-coherent radar can be summarized as follows:
- The phase locking process is not as accurate as a fully coherent system, which reduces the MTI Improvement factor.
- This technique cannot be applied to a frequency agile radar. Frequency change in a magnetron relies on the mechanical tuning of a cavity and it is essentially a narrow band device.
- It is not flexible and cannot easily accommodate changes in the PRF, pulsewidth or other parameters of the transmitted signal. Such changes are straightforward in a fully coherent radar because they can be performed at low level. It is also impossible to perform FM modulation (which is mandatory for a pulse compression radar) with this type of system.
- Second time around echoes are returns from large fixed clutter areas located a long distance from the radar. Because they originate from a large distance, such echoes are returned after a second magnetron pulse has been transmitted. However, they pertain to the first pulse transmitted by the magnetron. Such echoes are range ambiguous but, in addition, second time around clutter will not cancel. This is due to the fact that the phase locking of the COHO applies only to the last transmitted pulse.
MODULATOR REVIEW
Radio frequency energy in radar is transmitted in short pulses with time durations that may vary from 1 to 50 microseconds or more. A special modulator is needed to produce this impulse of high voltage. The hydrogen thyratron modulator is the most common radar modulator.
Picture 1: Thyratron Modulator
Picture 2: Thyratron Modulator of the russian
As circuit for storing energy the thyratron modulator uses essentially a short section of artificial transmission line which is known as the pulse- forming network (pfn). Via the charging path this pfn is charged on the double voltage of the high voltage power supply with help of the magnetic field of the charging impedance. Simultaneously this charging impedance limits the charging current. The charging diode prevents that the pfn discharge himself about the intrinsic resistance of the power supply again.
The function of thyratron is to act as an electronic switch which requires a positive trigger of only 150 volts. The thyratron requires a sharp leading edge for a trigger pulse and depends on a sudden drop in anode voltage (controlled by the pulse- forming network) to terminate the pulse and cut off the tube. The R-C Kombination is acting as a DC- shield an protect the grid of the thyratron. This trigger pulse initiates the ionization of the complete thyratron by the charging voltage. This ionization allows conduction from the charged pulse-forming network through pulse transformer. The output pulse is then applied to an oscillating device, such as a magnetron.
The Charge Path
The charge path includes the primary of the pulse transformer, the dc power supply, and the charging impedance. The thyratron (as the modulator switching device) is an open circuit in the time between the trigger pulses. Therefore it is shown as an open switch in the picture.
Once the power supply is switched on (look at the dark green voltage jump in the following diagram), the current flows through the charging diode and the charging impedance, charges the condensers of the pulse forming network (pfn). The coils of the pfn are not yet functional. However, the induction of the charging impedance offers a great inductive resistance to the current and builds up a strong magnetic field. The charging of the condensers follows an exponential function (line drawing green). The self- induction of the charging impedance overlaps for this.
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If the condensers are charged with the power supplies voltage, decreases the current and the magnetic field breaks down. The breaking down magnetic field causes an additional induction of a voltage. This one continues the charging of the condensers up to the double voltage of the power supply. Now the condensers would discharged (ice blue curve) about the power supplies resistance, but the charging diode cut off this current direction and the energy remains stored therefore in the condensers.
The Discharging Path
When a trigger pulse is applied to the grid of the thyratron, the tube ionizes causing the pulse-forming network to discharge through the thyratron and the primary of the pulse transformer.
Therefore, a current flows for the duration PW through the pulse transformer therefore. The high voltage pulse for the transmitting tube can be taken on the secondary coil of the pulse transformer. Exactly for this time an oscillating device swings on the transmit frequency. Because of the inductive properties of the pfn, the positive discharge voltage has a tendency to swing negative.
If the oscillator and pulse transformer circuit impedance is properly matched to the line impedance, the voltage pulse that appears across the transformer primary equals one-half the voltage to which the line was initially charged.
Thyratron Review
A typical thyratron is a gas-filled tube for radar modulators. The function of the high-vacuum tube modulator is to act as a switch to turn a pulse ON and OFF at the transmitter in response to a control signal.
The grid has complete control over the initiation of cathode emission for a wide range of voltages. The anode is completely shielded from the cathode by the grid. Thus, effective grid action results in very smooth firing over a wide range of anode voltages and repetition frequencies. Unlike most other thyratrons, the positive grid-control characteristic ensures stable operation. In addition, deionization time is reduced by using the hydrogen-filled tube. A trigger pulse ionize the gas between the anode and the cathode. Only by removing the plate potential or reducing it to the point where the electrons do not have enough energy to produce ionization will tube conduction and the production of positive ions stop. Only after the production of positive ions is stopped will the grid be able to regain control.
Because of the very high anode voltage the anode is attached most on the upper end of the glass bulb. Therefore the tube looks very ancient.
By the ionized gas it shines in the ionizated condition like a glow lamp.
Magnetron Review
In 1921 Albert Wallace Hull invented the magnetron as a powerful microwave tube.
Magnetrons function as self-excited microwave oscillators. Crossed electron and magnetic fields are used in the magnetron to produce the high-power output required in radar equipment. These multicavity devices may be used in radar transmitters as either pulsed or cw oscillators at frequencies ranging from approximately 600 to 30,000 megahertz. The relatively simple construction has the disadvantage, that the Magnetron usually can work only on a constructively fixed frequency.
Physical construction of a magnetron
The magnetron is classed as a diode because it has no grid. The anode of a magnetron is fabricated into a cylindrical solid copper block. The cathode and filament are at the center of the tube and are supported by the filament leads. The filament leads are large and rigid enough to keep the cathode and filament structure fixed in position. The cathode is indirectly heated and is constructed of a high-emission material. The 8 up to 20 cylindrical holes around its circumference are resonant cavities. The cavities control the output frequency. A narrow slot runs from each cavity into the central portion of the tube dividing the inner structure into as many segments as there are cavities.
| resonant cavities | anode | ||
| filament leads |  | cathode pickup loop | |
| Figure 1: Cutaway view of a magnetron | |||
 Figure 2: Magnetron МИ 29Г of the Bar Loc | |||
The open space between the plate and the cathode is called the interaction space. In this space the electric and magnetic fields interact to exert force upon the electrons. The magnetic field is usually provided by a strong, permanent magnet mounted around the magnetron so that the magnetic field is parallel with the axis of the cathode.
 Figure 3: forms of the plate of magnetrons | The form of the cavities varies, shown in the Figure 3. The output lead is usually a probe or loop extending into one of the tuned cavities and coupled into a waveguide or coaxial line. | |
| a) slot- type b) vane- type c) rising sun- type d) hole-and-slot- type |
Basic Magnetron Operation
As when all velocity-modulated tubes the electronic events at the production microwave frequencies at a Magnetron can be subdivided into four phases too:
2. Phase: velocity-modulation of the electron beam
The electric field in the magnetron oscillator is a product of ac and dc fields. The dc field extends radially from adjacent anode segments to the cathode. The ac fields, extending between adjacent segments, are shown at an instant of maximum magnitude of one alternation of the rf oscillations occurring in the cavities.
 Figure 5: The high-frequency electrical field | In the figure 5 is shown only the assumed high-frequency electrical ac field. This ac field work in addition to the to the permanently available dc field. The ac field of each individual cavity increases or decreases the dc field like shown in the figure. Well, the electrons which fly toward the anode segments loaded at the moment more positively are accelerated in addition. These get a higher tangential speed. On the other hand the electrons which fly toward the segments loaded at the moment more negatively are slow down. These get consequently a smaller tangential speed. |
3. Phase: Forming of a „Space-Charge Wheel”
On reason the different speeds of the electron groups a velocity modulation appears therefore.
 Figure 6: Rotating space-charge wheel in an eight-cavity magnetron | The cumulative action of many electrons returning to the cathode while others are moving toward the anode forms a pattern resembling the moving spokes of a wheel known as a „Space-Charge Wheel”, as indicated in figure 6. The space-charge wheel rotates about the cathode at an angular velocity of 2 poles (anode segments) per cycle of the ac field. This phase relationship enables the concentration of electrons to continuously deliver energy to sustain the rf oscillations. One of the spokes just is near an anode segment which is loaded a little more negatively. The electrons are slowed down and pass her energy on to the ac field. This state isn't static, because both the ac- field and the wire wheel permanently circulate. The tangential speed of the electron spokes and the cycle speed of the wave must be brought in agreement so.
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4. Phase: Giving up energy to the ac field
 Figure 7: Path of an electron | Recall that an electron moving against an E field is accelerated by the field and takes energy from the field. Also, an electron gives up energy to a field and slows down if it is moving in the same direction as the field (positive to negative). The electron gives up energy to each cavity as it passes and eventually reaches the anode when its energy is expended. Thus, the electron has helped sustain oscillations because it has taken energy from the dc field and given it to the ac field. This electron describes the path shown in figure 7 over a longer time period looked. By the multiple breaking of the electron the energy of the electron is used optimally. The effectiveness reaches values up to 80%. |
Modes of Oscillation
The operation frequency depends on the measurements of the cavities and the interaction space between anode and cathode. But the single cavities are coupled over the interaction space with each other. Therefore several resonant frequencies exist for the complete system. Two of the four possible waveforms of a magnetron with 8 cavities are in the figure 8 represented. Several other modes of oscillation are possible (3/4π, 1/2π, 1/4π), but a magnetron operating in the π mode has greater power and output and is the most commonly used.
 | Strapping
Figure 9: cutaway view of a magnetron, showing the strapping rings and the slots. Figure 8: Waveforms of the magnetron |
So that a stable operational condition adapts in the optimal pi mode, two constructive measures are possible:
- Strapping rings:
The frequency of the π mode is separated from the frequency of the other modes by strapping to ensure that the alternate segments have identical polarities. For the pi mode, all parts of each strapping ring are at the same potential; but the two rings have alternately opposing potentials. For other modes, however, a phase difference exists between the successive segments connected to a given strapping ring which causes current to flow in the straps.
- Use of cavities of different resonance frequency
E.g. such a variant is the anode form „Rising Sun”.
Magnetron coupling methods
Energy (rf) can be removed from a magnetron by means of a coupling loop. At frequencies lower than 10,000 megahertz, the coupling loop is made by bending the inner conductor of a coaxial line into a loop. The loop is then soldered to the end of the outer conductor so that it projects into the cavity, as shown in figure 1, view (A). Locating the loop at the end of the cavity, as shown in view (B), causes the magnetron to obtain sufficient pickup at higher frequencies.
 Figure 10: Magnetron coupling, view (A) |  view (B) |
The segment-fed loop method is shown in view (C) of figure 2. The loop intercepts the magnetic lines passing between cavities. The strap-fed loop method (view (D), intercepts the energy between the strap and the segment. On the output side, the coaxial line feeds another coaxial line directly or feeds a waveguide through a choke joint. The vacuum seal at the inner conductor helps to support the line. Aperture, or slot, coupling is illustrated in view (E). Energy is coupled directly to a waveguide through an iris.
 Figure 11: Magnetron coupling, view (C) |  view (D) |  view (E) |
Magnetron tuning
A tunable magnetron permits the system to be operated at a precise frequency anywhere within a band of frequencies, as determined by magnetron characteristics. The resonant frequency of a magnetron may be changed by varying the inductance or capacitance of the resonant cavities.
Tuner frame |  Figure 12: Inductive magnetron tuning | inductive tuning elements |
An example of a tunable magnetron is the M5114B used by the ATC- Radar
Figure 13: Magnetron M5114B of the ATC-radar
Figure 13: Magnetron VMX1090 of the ATC-radar
You can find further information on Radar systems starting here http://www.thehutchisoneffect.com/ws/Philadephia%20Experiment/radar-11.htm
- phase: Production and acceleration of an electron beam
- phase: Velocity-modulation of the electron beam
- phase: Forming of a „Space-Charge Wheel”
- phase: Giving up energy to the ac field
 Figure 4: the electron path under the influence of the varying magnetic field. | 1. Phase Production and acceleration of an electron beam When no magnetic field exists, heating the cathode results in a uniform and direct movement of the field from the cathode to the plate (the blue path in figure 4). The permanent magnetic field bends the electron path. If the electron flow reaches the plate, so a large amount of plate current is flowing. If the strength of the magnetic field is increased, the path of the electron will have a sharper bend. Likewise, if the velocity of the electron increases, the field around it increases and the path will bend more sharply. However, when the critical field value is reached, as shown in the figure as a red path, the electrons are deflected away from the plate and the plate current then drops quickly to a very small value. When the field strength is made still greater, the plate current drops to zero. When the magnetron is adjusted to the cutoff, or critical value of the plate current, and the electrons just fail to reach the plate in their circular motion, it can produce oscillations at microwave frequencies. |