"Collins Radio Company" by Sam Levy

Recollections of an Design Engineer 1952-1954

I wanted to work for Collins Radio from college, but did not pursue it. When I had my first years work done, I applied and got an interview. I said to myself, I'll fly, and charge them train fare. When I flew in, I saw a 6-foot high neon sign; "Collins Radio" strung across a hangar, and decided they would pay airfare. It was a hot day when I interviewed, I wore a loud homemade sport shirt, my Mom made it from colorful cotton Madras. My interviewer was in rolled up shirtsleeves, and thought my garb appropriate. I worked for Collins for two years, and was fired, it was their loss.

My first project at Collins was an FM substitute for a 3.45 MHz crystal source in a transceiver, so the ARC-27, an AM unit could transmit data using FM. The circuit was from Bell Laboratories, using a two section L-C delay line, the oscillator was a triode using the full length of the filter to set the 180 degree conditions of oscillation, connected to the grid and plate of the oscillator triode tube. I split the tuning capacitors, into two in series, to provide the correct amount of grid drive. The frequency modulation used a pentode reactance tube whose grid was fed from the mid-point of the filter, to obtain a 90 degree first grid drive; a second grid varied the reactive current with the modulation signal. I was working at the downtown site.

I built a model and tested it for supply voltage sensitivity, and found it excessive. I tried connecting the plate of the two tubes to opposite ends of the tank circuit, and the voltage sensitivity was greatly reduced. I tried the unit over temperature, and determined the capacitors needed for temperature compensation. On retrial, the temperature behavior had hysteresis, showing a lack of stability of the elements. I physically improved the inductor core mountings, and obtained a satisfactory result.

I then worked in the Aircraft Omnirange (VOR) group under John McElroy at the 32nd street plant. There wasn't any great work, but follow-up items, but it gave me a chance to get a good grounding on Collins products and procedures. I then worked on a TACAN Aircraft location project. It had been designed by ITT using dual grid subminiature gas thryatron tubes as logic gates, and these were failing in as little as 50 hours, due to gas absorption. I was assigned the IF and detector.

The gain was to be 120 dB, 2.5 MHz bandwidth, and 60 MHz center frequency. The detector was to be unusual, designed to reject pulse signals from adjacent channels. There were to be three detectors, low, center, and high frequency within the passband. The center detector was to detect positive output, and the side channels negative output, to cancel spillover from adjacent channels by selecting only positive detector outputs. It was a good idea, but of limited value, due to time dispersion and overshoots of the IF that I was not able to overcome.

The IF gain required, and the frequency involved, made a problem. It required 6 stages, with considerable filtering of filament, supply and AGC voltages. A cover over the stages had to be in intimate contact with the chassis dividers at each stage, to prevent feedback conducted by the cover. Isolating the double tuned coils from each other was accomplished by a bottom cover with nested internal lid, that made a reentrant trap which was successful. COLLINS got a lot of attention from SPRAGUE ELECTRIC, which was making available a ceramic substrate with resistors and capacitors applied, and pins for connections. I had them make prototype IF stages, with plug-in pins for the power and tuned circuit connections, and pins on top, passing through for the vacuum tube wire leads. I had Teflon single pin connectors set in the chassis for the circuit connections: it was a true plug-in stage. I heat sunk the cigarette shaped subminiature tubes to the top cover.

I reasoned that if I attached the external wiring near the front end of the IF, it would be sensitive to external signals. Connection to the detector end would export strong signals from the IF itself, so I connected the external wires to the mid-point of the IF strip. I have noted this in other designs, where strong signals from the IF output appeared on the connecting lines. It is a pervasive problem, as it does not appear high on the designers checklist, and is ignored, until found, rather late in the design and test cycle.

Following the receiver was pulse selection that would only pass pulses of 2.5 to 3.5 microseconds width, and pulse pairs of 9 to 11 microseconds separation. When I fed receiver noise into it, I got about 100,000 outputs a second. Noise contains everything in its random output. I was testing early silicon diodes, they were characterized in megohms back leakage, like germanium. I found them leaky, but when I turned out the bright light in the test box, the leakage fell way off. I was mystified, as there was no connection, and realized it was photocurrent. I called Hughes, who made their diodes black, and advertised photo-diodes.

One problem I was assigned was the Search/Track function of the ranging system. During the search phase, the interrogation rate transmissions to the central station was to be 150 PPS, of which 30% of the signals were returned by the central responder. The range gate delay was from a DC voltage developed by a 10 times reduction gear driven potentiometer in the range display instrument, and a resolver for precision. The electronic range delay was from a phantastron circuit, which I designed. I used a diode clamp to set the plate starting voltage and a second clamp from the potentiometer voltage to terminate the time delay. It started a delay gate, in conjunction with a resolver phase shifter. I used a Multiar un-blocking oscillator to make a precision early/late range gate. During search the gate window was opened wider in time, but it was not reasonable to sweep the range gate at the required rate, and determine whether the returned signals were synchronous with the interrogations, as there were not enough replies in the wide gate.

To avoid accidentally synchronizing with another interrogator, a concept called squitter was used. That is, the interrogation pulse was randomized by moving from pulse to pulse within the steady frequencies used for ranging. There was a problem as sometimes very narrow pulses were generated by coincidence between the steady and random timing signals. I solved this by employing a flip-flop which was either triggered or not, and used it's output to gate the next synchronized pulse to start a range cycle.

I took the approach of using an adaptive search, with the search rate derived from the time gated detector. I used a short time constant after the coincidence gate, so replies would charge the R-C, and used this voltage to run the search speed. A single coincidence would slow the search rate by 1/2, two in quick succession would stop the sweep, and succeeding pulses would charge a slower time constant, in series with the first. Switching from search to track required 5 pulses. Making the search rate a function of gated replies slowed the search only 2%, but was extremely effective in locking. When once locked, a tone available from the system was detected and added into the longer time constant, holding the system in the locked condition, even if pulse replies were denied for a period. This worked well, and solved several tough problems. I used it later, in a similar way, on another ranging system.

One problem was to obtain an exact frequency for the fine range resolver in the range instrument. A frequency of 4044 Hz was required, almost a forbidden region for precision. A toroid with an iron core was considered, but to heat the toroid from cold conditions was an impossible task. A surprising solution was found, using a long cemented flexure mode quartz crystal in a miniature tube envelope. The crystal had a dual set of electrodes, with voltage inversion, which permitted connections to the grid and plate of a resistance fed amplifier, for a precision oscillator circuit of extreme simplicity.

We had a test set for the Omnirange navigation receivers that had tone wheels for the various frequencies, and a precision resolver and angle dial. I ordered a similar set for TACAN, with tone generators and a pulse generator disc with 8 positive steps, and one negative step, for the "North" reference burst. I decided a number of things on that system. Harry had a problem finding a 15 Hz resolver, and I steered him to the RC type shown in the MIT Radiation Lab series.

After a year, I transferred to a group designing a communications transceiver in the 220 to 400 MHz band. Merle Hubbard designed a rotary tuner looking like a variable capacitor that tuned the 180 MHz range in 180 degrees. It had an inductance ring as part of the capacitor stator, and sliding contacts to the rotor, so the capacitor and inductor both varied. He even built a larger one for the final amplifier tetrode output that had an L profile inductance ring, and a plastic cam on the tuning shaft moved a disc capacitor in series with the output; to keep a match over the frequency range. They had trouble amplitude modulating the output tetrode linearly. I supposed that the screen of the tube needed modulation also, and it had only 12ma. current draw, so I suggested a resistive divider from the plate supply. It was perfect, modulating to 95% amplitude linearly.

Overall, it was a clever package, with a flat plate to mount everything. The modules all plugged into and mounted on it, wiring running underneath in 3/4 inch. Mounted to the plate was an axial fan. Where modules needed cooling, holes were added to the plate, and module. The heat transfer to external air was via a corrugated case, that had air flow in both internal and external ducting composed of the cover, and external fan. Modules were 4.5 inch square by thickness increments of 1.5 inches. The mechanical gearing interconnecting the tunable modules was flat and contained under the mounting plate and the modules plugged into the gear interface with captive Oldham couplers.

My module was the emergency guard receiver, fixed tuned to 243 MHz, sharing the antenna with the wideband receiver. There was a co-axial Tee in the feed line, and each receiver was to have a 1/2-wavelength cable, so that it would invert the short at the receiver input into an open circuit at the Tee.

Part of my equipment was a GR co-axial bridge that let me read complex impedance. I first found that the cable lengths in use were wrong, and reported my findings. John Goetz said to determine the correct lengths. I went to work on my input tuned circuit, I chose an inductive tap on the coil as my antenna match, and a capacitive tap for the tube input match. This configuration would have only one resonance, and offer low impedance at frequencies off resonance, which was inverted to an open by the 1/2 wave cable. I chose to give the tube and the coil an equal division of input energy. This meant that when the tube was powered the input impedance would drop in half. It did. I found the correct tap on the inductor was a 1/4-inch of wire, and I was going to put it across the co-ax input terminals. Merle Hubbard was near, he said don't do it, the first tech that sees that will cut it out, print it underneath, good advice.

I undertook the first printed board at Collins. I had a large Plexiglas sheet lightly scored in 1/4-inch squares, and applied red and black tape on opposite sides of the plastic. The photographer could use red and black backgrounds, and recover each tape color, without changing his camera set-up, assuring registration. When we assembled the first board, the resistors were larger than the ones we had measured, and they bumped. I used split terminals on the board, and simply laid tube leads and connecting wires in the slit, and soldered them. Connecting wires ran under the circuit board to the connecting plug and through the plug clearance hole to the opposite side.

I needed tuned IF transformers at 1.85 MHz, that would lay down in my module in less than 3/4 inch, and tunable from the ends, with terminals that would allow loading resistors applied to the coupled coils during tuning, so simple peak tuning could be used. I used powdered iron tuning cores, with an iron sleeve for magnetic shielding, in an aluminum cover for electrostatic shielding. Fiber end pieces held the tuning core, sleeve, and terminals. Fixed tuning capacitors were used inside the covers. The tuning cores would only penetrate to mid coil, to avoid false tuning peaks, a Collins normal practice.

The 5840 tubes I needed to use had 0.1 pfd of grid to plate capacity and 1.5 pfd grid to screen capacity. I used 100 pfd tuning capacity from plate to ground and a 1500 pfd bypass on the other end of the plate coil. This gave me a tuned circuit tapped at 1/15 and inverted phase from the plate, where I connected the screen grid for a balanced bridge to cancel the grid to plate feedback. I borrowed this from an article on power tubes, by Warren Bruene of Collins. The power isolation was 1500 ohms, which would disintegrate if there were a short.

The frequency scheme was to use a crystal oscillator to provide the second mixing frequency, and the 6th harmonic for the first mixer injection. I chose 34.45 MHz as the oscillator and the 6th harmonic as the first LO. My boss Harry said to double, then triple for the first LO. When tested, I heard a faint whistle as I tuned the input signal across the incoming frequency. I reasoned that I had not only the 6th harmonic, but also had some 8th, which mixed high side, giving me the interfering signal. I changed to a triple frequency oscillator output, followed by a doubler, with no whistle. That's what I planned initially.

It was theoretically not possible to achieve the bandwidth and side rejection that was needed from 3 identical double tuned IF transformers, but the alternative of more circuits would not fit. I decided to proceed, against theory. I used a screen injection second mixer, connected to the oscillator fundamental plate tank, two 1.85 MHz IF stages, and a diode detector. The mixer had higher output impedance than an IF stage, giving higher tank Q, and an overcoupled response. The diode detector was a heavier load, lowering the Q, giving an undercoupled tuned circuit response. The combination gave me the required response, using 3 physically identical transformers.

Since I had only one RF amplifier, I needed an efficient low noise first mixer, with low spurious response preferred. The Chief Engineer, Clem Arnold, came around every Friday, almost without fail, and I told him my problem. He directed me to a fellow who had a linear mixer. That is a real contradiction in terms, as to change frequencies, a mixer had to create new frequencies, or distort the signals. Well, this fellow had a linear mixer. He used a triode, with RF on the grid, and local oscillator on the plate, with the plate dc voltage lowered. This was the equivalent of a plate modulated RF stage, and it produced the fundamental and modulated sidebands with good linearity. I think I erred in not using a pentode mixer, with screen injection, simulating the linear mixer, as I could not meet the sensitivity requirement, the pentode gain would have helped.

I used a twin triode, with one side as the doubler to 6F, and plate coupling to the mixer, with 30 volts dc plate voltage. It was the best I could do, and the overall receiver met all but the sensitivity requirement.

I was challenged by the squelch function, which was to cut off the audio output, when the signal was below usable level, operator adjustable. We were advised not to use tubes near cutoff, as unreliable, not to use less than 1 volt bias because of induced grid current; and limited plate current, voltage and wattage also. I decided to follow the rules. I could get a fair plate swing using a dc amplifier from the AGC, and started that way. I decided to couple a dc amplifier output to the audio amplifier grid bias with a diode. When the dc amplifier plate voltage fell, the diode would couple the cutoff voltage to the audio stage. When the dc amplifier output was higher than the audio amplifier bias, the diode disconnected the dc amplifier, and the audio amplifier performed normally.

It was not possible to measure the input signal change needed to operate the audio squelch, but by measuring the dc bias change with signal, one could calculate that 0.05 dB change would fully operate the squelch. Not only was it functional, but it lived with all the reliability guidelines for the tubes, and was non-critical of components. I might have used a diode gate only, if I had thought about it more, but previous art led me to follow standard practice.

The audio response had severe shape limits, as well. To aid the low frequency cutoff, I used the AGC response speed, allowing it to respond at the lower audio frequencies, aiding the cutoff. By controlling coupling capacitor sizes, and using some shunt capacitors for the higher audio response, I made the required response. The output transformer low frequency response was included in the remedies.

At this time, Fedde and Rowley were trying to make a phase shift audio oscillator, and could not make it work with a lower gain tube, with greater grid to cathode spacing required for reliability. They were searching for solutions, and I offered one. They were using 3 sections of phase shift, each one cut the signal in half, for a 60 degree phase shift, with an overall loss of 8 times in signal. I suggested 4 sections, 45 degrees each, with an 0.7 reduction in signal per section, and an overall loss of 4 times; success. They were also searching for a 150 volt dc supply source, I suggested rectifying the 3 phase 110 volt, 400 Hz that they were given. Too easy. These fellows were trying to make a reactance modulator with only one phase shifter. They experienced AM as well, and I explained they needed a double section phase shift. When built, they said how do we adjust it, I said "for no AM". You could see the AM phase reverse, and null, as the phase was adjusted.

Pete Viterisi had the main receiver IF strip and he was having trouble with the audio response due to AGC peaking the low frequency audio. I advised him that he had a second time constant in the loop, it was the RC grid time constant. Reducing it brought the problem to acceptable levels. That was 5 assists for me, the modulator, oscillator, reactance tube, AGC and dc power. I'm sure there were others. I worked with my mechanical designer using a large T extrusion for the chassis, and a wraparound extrusion, welded to close the corners. I designed rolled over spring clips to hold flat covers on, and they really held.

Collins had a model shop that worked nights. If you turned in a requirement by 3:30 p.m., you could have it next day. I mean in quantity. I had my IF transformer components, my cover clips done right now. They had cut, punched, formed, heat treated, tumbled and plated 50 clips overnight. What a boon to the hurried engineer. They saved your time for creative work, and probably cut project time by 1/3. Another big saving was the open stock of parts in your immediate area, and the open stock room for more expensive parts.

They had punched cards for part numbers, and you entered project number, number of parts, and signed it, dropped it in the box. They also had a parts window for instant service on rare and valuable parts. They had a coil winding expert, Archie, downtown that could produce the most complex windings, on short notice.

They had components specialists in purchasing, that could advise you, and standardize the parts in use, and do the paper work for you. They acted as liaison to manufacturers, keeping advised of the latest developments. Add more time savings. They had a bullpen work area for junior engineers, and draftsmen. A draftsman-designer sat next to me, and we really worked together. He could discuss his questions with me easily, and was not able to work open loop.

Surrounding this area were glassed-in two man offices with the engineers, and in single man offices were the senior engineers. You could see if someone was in, if he was busy, at a glance. The supervisors were in enclosed offices with a shared secretary. Those secretaries were fast and good. Alice could take your scribbles, put it in businesslike text, type it and the envelope, and put it on your desk before you could take a quick smoke.

Collins set standards of excellence in your work, too. I told my senior engineer that I had finished my IF strip. He asked me, do you have the frequency response plot at 3 AGC levels; high, room and low temperatures; Vs plate and filament voltages; the detector output plot to overload; high and low limit tube behavior... I went back to work, and understood what completion meant at Collins. They wanted a producible, quality product that was not dependent on selected parts for performance. Where selection was required, it was done rigorously. By direction and example, you learned what Collins meant. A specific example, the federal standards for omnirange transmitters were changed, receivers from other suppliers had to be changed, Collins gear worked right through the change, due to the performance margins designed in.

Some of my managers were not technical, but you could tap experts in their field, and some people worked to extend that expertise, as their contribution. Hubbard and his tuners, Bruene and his tube work, and they did not hesitate to bring EIMAC in when their tubes had problems, or transformer people, or as needed for real results. They kept some excellent workman for prototypes, and they were not above telling you what they thought about your design, or how to make it better, or easier.

Once, in squeezing past a desk, I broke a piece that was hanging over the edge from a balsa wood model. I caught heck, later the fellow came to me, and said, I never did like that plug sticking out. It's now in the back where it belonged, all along. I set an aircraft ATR case standard, with my hip. They had a novel way to start a production line. Their best technicians, some from each group, were assigned positions on the production line, and given such assembly instructions as were prepared. As work flowed down the line, any problems were called to the attention of engineers, and corrections made to the procedure as needed. When the problems had been worked out, production workers were put on the line, with the technicians acting as instructors, until the line was moving by itself.

On one occasion, Collins equipment was being assembled by another company. Gene Habeger received a telephone call that an antenna cable would not reach between the assigned connectors. He tried it, and sure enough, it wouldn't reach, so he went to the line to see what he was missing. He found a really big, strong woman simply forced the cable in place, so he called, and said, just put a bigger girl on the line.

Once a worker took it on herself to relocate a part. Soon, the equipment would not pass its spurious test, and an engineer was called. He studied the wiring model, assembled on a Plexiglas chassis, and discovered the misplaced part. They put a replacement worker in for the erring girl, and had her stay after hours, and fix every mistake herself. To go to the model shop, I had to pass the production line, and they would whistle and catcall as I passed. I just laughed it off.

I later became acquainted with one of the production ladies, Amy, she was the only person in the plant who could put a reluctant "Autotune" head right. Her method was simple; she did it by the book, using tools and gauges, and setting each tension correctly as she went.

Collins had a training school for their inexperienced workers. They learned to read meters and adjust things, to use tools, and to solder. For practice, they disassembled our breadboards. They could work anywhere on the line, or test stations, with little instruction. They always had printed matter to refer to, as to the settings, readings and checks to use.

A technician provided me with a tool steel rod to make a punch, to punch some screw holes in gasket material. I chucked it in a lathe, and drilled a hole the size of the hole I needed. I used the cross-axis feed to turn a taper, to make a sharp edge. I ground the back edge so it would not splinter, and oil hardened it. On my first hammer tap it flew across the bench and hit the wall. The tech said did you harden all of it? I had to draw the temper, and harden just the punch end, then it was fine.

I went to John Goetz and said someone stole all my tools! He said let me see, and he went around the lab and picked up all my tools. I asked how he did that, he confessed he used them, and left them all over, as it was the only one unlocked on the weekend. It was locked after that. Collins tool room sold small metal adjustment screwdrivers 8/$. So many of mine were stolen, during the day I got dollar after dollars worth until I could keep a few.

Collins standard fractional dimension tolerance was 1/32 inch; their standard decimal tolerance was 1/1000th inch. When you hung a door on a Collins cabinet, it fit. They printed a stock record book from their computer every 2 weeks, a dozen copies. Their standard parts book was a shelf 40 feet long; much of it showed older parts that had been superseded, and the new part to use. I looked up a 120pfd, negative 220-PPM temperature coefficient capacitor, their reorder quantity was 60,000, and the order quantity was 120,000. Parts were pre-assigned to projects, and when you needed more than a few, you had to have a project engineers permission to withdraw them. Generally, the answer was yes, we have 10% spares for that part.

Art Collins ham setup had the latest COLLINS gear. He had a three element 40 meter beam, that served as the hat on a discone vertical for 80 and 160 meters. He had beams on the 20 and 10 meter band. His back yard and my back yard abutted on Cottage Grove, in Cedar Rapids, Iowa. There was a story told that at a NY IRE show, a salesman told his boss: watch that door, it has a sharp corner. Soon his suit was torn by the boss opening the door into him. He put a new suit on the expense account, and it went through without comment. I remember Gene Habeger asked if we would be on overtime, and was assured we would be on overtime for the foreseeable future. He bought a house, and immediately went off overtime. He figured the family would have to eat beans to survive. He was called to the airport for trouble with a Collins radio, he came back all irritated, and said the trouble was all in the cockpit, a standard phrase for user mistakes.

Collins had designed a ZIFOR, Zero Indicator For Omni-Range, a calibrating tool for the Omnirange receivers. After it was demonstrated successfully, United Airlines asked if it was rugged. Art said, lets' find out, opened the nose door of a DC-3 and flung it out 20 feet to the tarmac. Gene said his heart was in his throat; it was not designed for that. Art said go get it, it worked, and they bought it on the spot. I recall that he liked the Amateur radio section, so they got rubber mats in their labs.

Collins was strong in its commitment to reliability, long before everyone else. In one case a transformer failed, analysis showed corrosion on the copper wire near the nylon bobbin. Since there was no reason for it, the bobbin was suspect. A bobbin was wound with two bare copper wires, side by side, and put in a temperature and humidity chamber with a voltage applied between them. Another bobbin was washed with alcohol, and similarly tested. The original bobbin turned green immediately, the other was normal. Collins chemists said it was a trace of silicone mold release compound on the bobbin. He said silicone grease was incompletely polymerized and continues to link up with heat and pressure. It released nascent or mono-atomic fluorine, which would eat glass. Silicon oil was barred from general use a damping oil, lubricant etc.

A transformer failed under vibration. On disassembly, one wire was found stuck in the header terminal without being soldered. Collins blacklisted a major company for this omission. It was explained that if I could build a circuit and make it work with high gain tube types, and a low gain type, it was probably a good design. We actually had an expensive set of high and low limit tubes in our stock for use in testing. Much of this information was not on paper, but we learned it from our older mentors. I recall an Eimac tube fell apart in use, an EIMAC employee examined it, and found soft solder, they were supposed to use silver solder.

They had a glass blowing lab that could make anything. One of their products was an external grid triode, as Westinghouse had a preemptive patent. All the customers knew that they were supposed to replace the tube with standard types.

Collins made glide slope receivers for landing profile guidance. One design used radio signals up to 1 Hz, and an accelerometer to provide information above that frequency. They had a capstan driver to replace hydraulic units in aircraft controls. It used an AC motor, and two magnetic particle clutches for the two directions. It was put on continuous test raising and lowering a weight; they built a soundproof box over it. Hydraulics still are a major aircraft problem, leakage, fires all the problems. Collins designed a landing system that you simply crossed the pointers to fly the path. They had a pen recorder plotting all the landing paths. I was allowed to try it, and I threw it off, then followed the pointers to see what path it would make during the correction, it was quick and smooth. Suddenly the needles went all over the dial, they said; you landed a minute ago. They made a location computer using omnirange angle information. Collins was in the forefront of advances.

Someone said there was letter addressed to the Colon Radio Company in Peter Rabbit, Iowa, delivered to them. I can just see some guy with a cigar in his face dictating that. When the new plant was built, they made the parking lots bigger than they thought they needed, it filled instantly. They put the manhole where the outside power connected to Collins lines underground at the low point of the lot. With the first good rain, it filled with water shorted the insulators, and the water boiled. They could not get pump suction, as the water was so hot. They closed the plant for the rest of the day. The Power Company paid; I needed that information later.

The construction of the new plant used new techniques. They cast the floor slabs, and then cast the walls lying flat on top of them. They lifted the walls in place so fast the plant grew quickly. They had wire mesh in the walls, which they connected at the joints, to make a screened enclosure. They hung steel rafter beams, and dropped wires from them for tracks to support the ceiling. They slid ceiling 'tiles' down the long tracks, and put it up rapidly. When the air conditioning motor was connected, the electricians did it wrong, and blew it out. They had a plant full of electrical engineers that could have helped. They had a TV to check for interference around the plant. One afternoon we received a New York station for about half an hour.

Collins also had some unusual programs, one tracked the sun by it's microwave noise. Another broadcast 50KW short wave down a rhombic long wire directive antenna toward Sterling, West Virginia, the WWV station, where they recorded the signal strength over time. Instead of passively terminating the antenna end, they phased and matched the signal, and sent it back to the transmitting end. They had a superbeam power tube so big a man could work inside it. It would consume 10 megawatts, in the middle of the night by arrangement with the power company. The transmitter fed a copper horn out to 20 by 40 feet, where it changed to chicken wire. It lay on the ground, and when the moon passed in the beam, they could bounce signals carrying 30 teletype signals back from the moon. Collins later used forward scatter microwave signals to communicate with the Dallas plant. For reliability I believe they put in a repeater station mid path.

Bruce Majerus, Chris Fedde, Bob Rowley, Pete Viterisi, Harry Stillwell, John Dickerson, Gene Habeger, Dick Bousek, John Goetz, John McElroy, D.C. Clem Arnold, John Dalton, J.P. Giacaletto

By: E Samuel Levy 754 Temple St. San Diego CA 92106-2830
tel. 619-223-6292

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