Shortly after joining RAND, the countermeasures group hosted a seminar on the subject, inviting people in the field from around the country and England. As the newest member of the group I was assigned the job of preparing a record of the meeting. For this purpose I used audio recordings made of the proceedings, my notes and notes left by some of the speakers. Afterwards I spent many hours listening to the recordings (they were very poor), gathering all the information I could, and proceeded to write my versions of the talks. As each was finished I sent it to the speaker for his approval. I knew I was doing a good job when one speaker wrote back that he didn't think what he received was quite what he had said -- but that he wished it was. The record became a Rand document that appeared as a (classified) small book.
I was not happy with the second-hand type of work Rand was doing (their charter prohibited hardware work in competition with commercial companies) but became involved in a project where Rand had given a contract to a local company to develop a "gap-filling" scheme for Air Defense Radars. Since mountains can create shadows where a radar can't see possible target aircraft, Rand had proposed that smaller radars be set up in the shadow regions with the information relayed to the major radars where it would be superposed on the locally-picked-up signals to fill in the gaps in their radar coverage.
The radars were available but not the relay link. It was proposed to send the information on regular phone lines but, since the radar signals came in much too fast for such lines, they had to be slowed down.
Our first system worked well on the first telephone lines used where, in effect, the two ends were directly connected by a wire line. But when we moved to a different area the operation was very poor. The telephone companies have a number of ways of transferring information, the simplest being to send it directly along wire lines. But that allows only one conversation per line so, in effect, they use small radio transmitters for each conversation, each on its own frequency, and install a small radio for each at the receiving ends. So, in effect, for long distance telephoning, our voices might go over the lines via small transmitters and be selected for the listener by correspondingly-tuned small radio receivers.
We were familiar with this, but not with the various schemes used for squeezing more messages on the lines. Voice signals can be considerably distorted before losing its basic quality -- but not the slowed down radar signals; the solution required cooperation from the telephone company. Today computer data is being transmitted at a fast rate on all lines, with the telephone company making certain that the digital pulses are transmitted without the excessive spreading that gave us a problem. (Increasingly today the "lines" are very thin glass fibers, each capable of carrying many conversations, digital signals or TV programs, with transmission in the form of very short digital pulses that can be steered to the appropriate customer by computers).
Part of the problem was to recreate the radar image. This took me, as a consultant, to the Boston area where the Lincoln Labs of MIT had gotten into the act. The family arrived in the spring and rented a house and our boys were soon delighted when there was a late season snowfall sufficient for them to play in! Irv started school there and found himself behind -- but caught up quickly. With no big responsibility for the house we managed to travel around and saw much of New England. The work was going well and we all enjoyed the break.
I had originally planned to be at Lincoln Labs only three months and had arranged to pick up a new car in Detroit on the way back. With the delay, Irv and I journeyed to Detroit, picked up the car and drove it back to the Boston area. We had visits from the Handelsmans, Mentzers (also from Ohio State) and their friends in the area. On our way back to California we stopped at Rome, New York, where we visited the Handelsmans and in Columbus where we visited the Weimers; he had been a classmate before the war and stayed on as a Professor.
Later, Rand was involved with an experimental program to train the Air Defense Command. A computer was used to plot the positions of aircraft that might be expected in the vicinity of a radar at the time represented in a problem. The plots showed up as "ones" on wide sheets of computer paper, in positions to simulate the "blips" or bright spots corresponding to the reflections from aircraft as seen on the radar displays. Machines that flipped the paper, a page at a time at four pages per minute, were used to present the information to the operators in simulation of the four scans per minute of the radars used at the time.
At first University of California at Los Angeles students were used as operators to determine the probable effectiveness of such training. The problems involved mostly simulated commercial flights that could be identified from their flight plans, as passed to the students by a script (commercial planes are required to file flight plans with the local Air Traffic Control, telling when they will be passing a set of check points). Occasionally, a plane would be included that could not be identified by a flight plan, so the students would "scramble" a make-believe interceptor aircraft by calling commands to a member of the problem team. If he was satisfied that a real interceptor, answering to the commands, would be able to "see" the "aircraft" he would call the operator and identify the plane as read from his script. It might be a plane that was somewhat late at its checkpoint, for example, in which case the interceptor would be released to go back to its base. The first time the referee reported a "red star" on the unknown plane the operators didn't know what to do! Many years later when the Russians shot down the commercial Korean plane I thought back to this exercise.
The Air Force became interested in the program and sent out a group of their people to take part in it. It soon became obvious that the crude equipment used did not prevent the students from being completely absorbed in the problems -- they were shaken when an "enemy plane" was able to pass through the "defenses" and "bomb" Los Angeles!
The Air Defense Command decided that it would be very valuable if the training could be conducted at the radar installations, so the "System Development Corporation" (SDC) was set up to implement the program (it was not appropriate for Rand). Mr. Kappler became president of the new Corporation and I became head of the related engineering activity.
The program had many interesting facets. Of most interest to me was the "Problem Reproducing Equipments" (PREs) to be delivered to every radar site. They would have to feed simulated signals into the radar systems that would allow essentially normal operation of both the surveillance radars (360° coverage around the radar) and of the "height finders" used to determine the altitude of targets of interest.
The height-finder implementation was awkward because the Air Defense Command was then using two completely different types of radars for the purpose. One, with relatively poor performance, was similar to the surveillance radars in that they searched continuously through 360 degrees using a "tilted-fan-beam" antenna so that, as they rotated, they would pick up targets later than the surveillance radars by an angle that depended on the elevation angle of the target. (The complete radar included three transmitters forming a vertical-fan-beam, for the surveillance operation, and two that formed a tilted-fan-beam for the height finding, all mounted on a merry-go-round-like platform). The more modern height finder nodded up and down in elevation, so that it swept through a vertical fan; it required the operator to command the antenna to point to the target so as to bring it into the field of the nodding antenna.
It was decided that the input to the simulators would be in the form of 70 mm movie film and calculations showed that several million feet of the film would be required each year when the program was fully implemented. It was thought that Eastman would give us a good price for the film, but Eastman wasn't impressed -- we were told that the movie people were using that much film every day!
As the films would have to show simulated tracks for many aircraft, it was necessary to prepare them automatically with a computer. This required a cathode-ray tube output from the computer to expose the film, a novel bit of technology at the time. The bright spots on the CRT created black spots on the negative film, as usually developed, and we wanted clear spots on opaque film to input to the simulators (it is easier to see bright spots on a dark background than dark spots on a bright background). As we didn't want to make copy prints to reverse the images, we went back to Eastman for advice, but with no success.
About this time a photographer with the group looked at an old photography manual and learned that one could develop black and white film normally and then wash off the developed silver without bothering the unexposed emulsion. It was then a simple matter to re-expose the film to light and develop it again, making it black except where the silver had been washed away and leaving clear areas where the original spots had been. An automatic film developing machine was ordered for the purpose.
The layout of the film and the implementation of the simulator are described in Appendix 7.
The program was first implemented at the radar site at Boron, California (North of Edwards Air Force Base on Route 395) which I visited many times. Operation required the PRE to be locked into the radar system so that the synthetic targets could be read out as simulated radar "blips" when the antenna was pointing in the proper direction and at the required time after the radar "main bang".
The first test of the ability of the equipment to follow the antenna rotation revealed a problem; it wouldn't! Since it had "locked on" an equivalent rotation on the bench we looked for differences. The radar antenna rotation was reported to the displays by a dual system, one operating on a one-to-one basis with the antenna, so it was not very accurate, and a second operating through sixteen-to-one gearing, that yielded the required accuracy (but it could lock on any 360/16=22.5° interval, so the one-to-one system was required to get it started).
I asked if their system was operating properly and was assured that it was. I then suggested that it should be possible to disengage the one-to-one system without hurting the operation, since the sixteen-to-one system should have control. The technician agreed, so we did -- and all of a sudden the displays were rotating backwards! The operators then admitted that the azimuth lines on their displays (0 degrees, 10 degrees, etc.) had been off a little in direction, but that they had paid no attention to them because they were using the nearby mountains as their guide! We modified our equipment so that it could follow the antenna rotations better.
PREs were subsequently installed at San Clemente Island (back of Catalina, visited either by boat from Long Beach or by small plane), Santa Rosa Island (off Santa Barbara, visited by PT-boat from Port Hueneme), Mount Palomar (not far from the Observatory) and Cambria. For Cambria, we flew to San Luis Obispo, rented a car and traveled along Highway 1 with instructions to look for the radar along the highway near Cambria -- we didn't see it. At a gas station in Cambria we were told to go back and look for the "Weather Station". The installation at Cambria, installed during WW II when it appeared that there might be a Japanese attack, was the first such station in the U.S. and had been secret -- calling it a weather station kept interest in it low; the sign had never been changed!
To implement the program, analysts at SDC studied the air traffic in the L.A. area and, when a choice was made of the time to be simulated, provided inputs to the computer for all of the likely flights. The computer then prepared films for each of the five radar sites. A script was also prepared for each for use by the "problem team" and "umpire". As mentioned above, in real life, airplanes file flight-plans with Air Traffic Control before taking off and these are relayed to the Air Defense Command so this function had to be simulated. If an airplane could not be identified from its flight plan, a simulated interceptor would have to be "scrambled"; for the simulation at the radar sites this originally took the form of an old Navy Electronic Simulator that a team member could "fly" in response to commands from the radar operators (it produced a realistic blip on the radar displays). When a member of the problem team judged that an interceptor could see the target aircraft, he would read the identification from the script and pass it on to the radar operators; the interceptor could then "head for home" if the target was "friendly" or "engage it" if it was not. To achieve a better simulation I had the angle dial mounted on magnets so it could be offset to simulate wind that would affect the flight path.
The umpires knew, before each exercise, what the problem areas were likely to be, so after observing the exercise they could provide quick feedback to the crew on their problems and suggestions for improvement. The crew was then left to determine how best to improve their performance (for example, by shifting crew members around the various functions).
The films were mounted in the PRE at each site involved in an exercise and the equipments were turned on at the same time. A simulated commercial flight from San Diego to San Francisco, for example, might be observed first by the radar at San Clemente Island and later by the radar at Santa Rosa Island. For this situation, the flight should have been identified by the crew at San Clemente and they should have passed the information along to Santa Rosa so the crew at Santa Rosa wouldn't have to worry about that flight when it came into their area. Training for this function was realistic, as both sites were involved in the problem and were communicating normally.
During the training exercises the current air situation was always monitored by one operator who sat out the problem. The exercise could be quickly aborted if required to handle a real-life emergency.
The radar at San Clemente Island led to an interesting observation: The Laguna Mountains (where Mount Palomar is) could generally be seen on the displays, but sometimes they were not visible. The radar was at a distance from the mountains where the curvature of the earth made only the tops of the mountains within a straight line path of the radar and therefore visible to the radar, but on some occasions the atmospheric conditions bent the rays upwards so that they missed the mountains.
An unexpected problem slowed the extension of the program to other radars. The film reading scanners required 27,000 volts to get the required bright displays. The supplies that went into the original "breadboard" units provided trouble free service during the tests in the local area, so no problems were anticipated for the production units. When the Air Force decided to go ahead and procure the production units, the manufacturer of the supply went back to their capacitor vendor and were told that they would have to use a different capacitor because the original did not satisfy the requirements. Unfortunately, the replacement was larger, so the supplies had to be redesigned. When I left the program in 1957, the power supplies were still failing! The larger capacitor required closer spacing of some connections and the oil in the supplies was being contaminated during the assembly process. Bits of hair were getting into the oil and would move into the high field regions causing sparks that would take out the supplies. The manufacturer learned about clean rooms and the necessity of good housekeeping!
I prepared specifications for a new interceptor simulator that would include all of the features we wanted and shortly after, left SDC for Ramo Wooldridge (R.W.).
On to Ramo Wooldridge
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