ARMY RADAR HISTORY records that the Fort Monmouth laboratories started their R & D on radio reflection and detection using microwaves in the 9 centimeter band, using the mini-powered magnetron which was available in the early 1930's.  But ranges on airplanes and ships were hopelessly inadequate for any military application.  High promise of microwaves had years to wait, for it was not until early September, 1940, that the Sir Henry Tizard Mission of Great Britain presented the U.S. with models of their multi-cavity resonant magnetron, with power potential a thousand-fold greater than early American designs.
     Frustrated by the small ranges possible through use of only watt-producing magnetrons, in February, 1936, Signal Corps interests shifted dramatically downward to the 100-200 megahertz region of the spectrum, almost the entire laboratory's effort being realigned to expand the new technology in a spectrum area where components were available.  The idea was to meet the military requirements, and forget the size of the antennas needed to do the job.
     As time rushed on toward the Pearl Harbor disaster, it needed no great military genius to sense the threat of the war clouds over Europe, now thundering and raining death, as Hitler's military might moved on relentlessly; or the same across the Pacific, where Hirohito's War Lords were growing increasingly belligerent towards U.S. interests.  FDR's crystal ball was ablaze with predicted troubles ahead for our peace-loving nation, troubles both from east and the west.
The First Crisis
     THE FIRST CRISIS: Facing this two-edged threat, our military strategists were in complete agreement that the Panama Canal was the most vulnerable spot in our hemisphere.  A well-laid bomb in any of the locks, either dropped from the air, or carried in the concealed bottom of some innocent-looking tramp steamer, could raise complete havoc with our ocean-to-ocean shipping, and of course, disastrously upset Navy strategy in how to deploy ships.
     The Laboratories at Fort Monmouth had long been involved in seeking ways and means toward meeting threats to "plush targets" such as the Canal. Starting in 1930 the emphasis was on underwater sound since the threat was then mostly from battleships and submarines.  For a time, the infrared was stressed, but fog, smoke, rain, or snow were natural barriers.  Following dramatically successful tests of 100 megahertz radar in 1937, besides exploiting this new technique for fire-control purposes, we moved rapidly toward applying this technology to the early-warning problem.  With enough advance knowledge of an approaching enemy armada, our fighter craft would have enough time to engage them far from their in-tended target-with ground-based anti-aircraft guns also alerted against those which might have slipped through the outer perimeter of our aerial defense.
Working feverishly on this pro-lem, our initial success was formally demonstrated in November, 1939, when we successfully radar-tracked a flight of high-flying B-17 bombers, from the Jersey coast to the end of Long Island and back-one way,

     Idea Nears Success
     About this time, an idea of mine for generating much higher frequencies, started showing some spectacular success.  We were closing in on the invention and development of a new and novel design in the world of the electron tube.  It wasn't just an electron tube; it was an entire radar transmitter placed in an evacuated glass envelop.  Driven by pulsed "lightning bolts" of 20,000 volts, it would produce a peak power output of 250,000 waits, at the then fantas-

Research Completed
     Our research and development now completed, we turned to industry for production.  The final model for mass-production came from a small west coast company owned and directed by William Eitel and Jack McCullough . . . EIMAC, in San Bruno.   They called it the "Zahl" tube-the Army called it the VT-158.
     Anxiously awaiting for these first factory-made tubes, was one of the Army's most brilliant electronics engineers-John Marchetti.    With his team of supporting engineers and technicians, soon he had a radar "bread-board" model available for test.    Standing ready for these tests was the first picket-ship-to-be-the trim 125-foot M.S. Nordic, docked in nearby Belmar, N.J., complete with crew.
     Now at war-because of high secrecy, when at sea with the radar, the Nordic would always be escorted either by a Navy blimp or destroyer (or both) carrying depth charges.  
We knew from damage to ordinary shipping, that German submarines lurked in coastal waters.   One test will never be forgotten.    About 40 miles off the Jersey coast, a German submarine surfaced, and its periscope settled on our SECRET radar, but not for long; its view soon included the blimp and destroyer closing in with depth charges.   The sub-crash-dived, and may have saved its life-but only because it had sur-faced very close to our Nordic. Dropping of depth charges had to be delayed, lest they get the Nordic too. When the Nordic lumbered out to a safe distance, bombs were dropped . . . but no oil slick appeared.
     Hitler would have liked that prize! 

Tests Prove Successful
     While the tests of this lightweight radar turned out very successful and gave substantial ranges on aircraft flying as low as 15 feet above the water-as we worked on, the pages of the calendar had also been falling. The year 1943 arrived.  The threat against the Canal had fallen off to where the picket-ship idea was no longer considered necessary-our Navy was in control of off-shore waters!
     Yet here we had a lightweight radar which could be carried by
hand, or easily air-transported, set up and operated by a four-man crew-range on aircraft, 120 miles. The Air Corps became very inter-ested. At their request, on March 1st, 1943, a set was flown to Orlan-do, Florida, and tested in compari-son with three other man-packed equipments.  Our set was a winner, and 900 sets were ordered (Zenith), both for U.S. and British use.  It was called the TPS-3; and soon the little midget became a global traveler, being at home in all combat theatres of the war - 25 of them even crossing the English Channel on a date picked by General Dwight D. Eisenhower . . . D-Day, June 6th, 1944.   So my "First Crisis" ends.

The Second Crisis
     THE SECOND CRISIS: The scene now shifts to the other side of the world.   In the South Pacific, combat was intensifying as American and Allied forces moved from is-land-to-island-but the cost in human life was great.  Well over half of the casualties experienced by our ground troops came from Japanese mortars.  Through numerous messages to the States, General MacArthur pleaded for some break-through in technology which would help in the quick determination of the ever-shifting position from which these hell-created torpedo raindrops were fired -generally in bursts of hundreds-and then to a new firing position.   But to direct counter-fire, one had to know where the enemy was, and quickly before he moved.  Unlike Field Artillery guns which made a big bang, mortars would only make a small puff, inaudible except at close range ... and the distances were always great, with jungle camouflage adding to the problem.  Low frequency radars were no solution to the problem since the small mortar shell was nothing like the target of a big airplane-and in the jungle, small weight and agility were most important.
     At Fort Monmouth, mulling over this crisis in the Pacific Theatre, we sweated day after day, leaving no technological stone unturned, as we searched for some potential scientific solution.  As I remember, one day a group of us were together, when the murkiness of our combat-oriented atmosphere suddenly showed signs of a clearing.  Again it was Marchetti

TPS-3 Ready For Testing
     A few days later, Marchetti and I visited Island Beach, a desolate bit of coastline halfway between Fort Monmouth and Atlantic City. The TPS-3 which had been modified was ready for test. Some distance away, an Army mortar crew stood ready to fire shells approximating Japanese dimensions.
     The big moment had arrived!
     Our radar pointed at the mortar site about a mile away.  By radio, the signal was given "Fire when ready."  Anxious eyes watched both the radar oscilloscope and the firing site. THEN-simultaneously, with the small puff of smoke from the mortar, there appeared a sharp radar "blip" with each shell fired.
     The idea had worked!
     The rest of the afternoon was spent extending the range between the radar and the firing mortar - the results were spectacularly good; several miles, easily enough for effective combat use. While the calculated positions of the firing mortars were not exact, they were much better than anything MacArthur's men could do with what they had. 
The only question now was-how  rapidly could the modification kit to the TPS-3 be designed, produced, and fielded?  The news of this new break- through in mortar detection quickly reached the combat areas in the Pacific Theatre.  Through various channels, the word came down of utmost urgency and top priority- even high-level visits by combat 
officers were suggested, should such serve to expedite delivery.  But Marchetti needed no further urging.   Overnight, he turned his laboratory into a dedicated group "swearing" to 
work around the clock, until a first few of the modification kits required could be put into a truck bound for Newark Airport - and then with quick shipment to the Pacific Theatre . . . as industry geared up simultaneously for mass-production.

Action Was Everywhere 
     Twenty men and a Miss Helena Schroeder starred in the strange bizarre war-time drama.  Days and nights passed -a few catnaps, sandwiches, and much coffee.  Action was 
everywhere.  Even Helena on the telephone, filled the air with choice phrases, she called out for supplies, food, and the like.  When she talked, which was often and dramatcally, her vocabulary frequently suggested one made famous by the Missouri mule drivers of World War I; but she got attention, and results.  The Bless her! She is now gone; but as I
put it later, when she spoke, "The stars and stripes flew violently in the breeze!"
     After 96 consecutive hours of activity, a truck came up, and the first modified equipments were enroute on their  long trip across the Pacific.  The set was called the TPQ-3, going
to war, probably with an all-time speed record for conception, production and delivery.  No sleeping pills were required for the long rest which soon engulfed this noble group.   As
supervisor I didn't care if they slept for a week; they had earned it!
     As they slept, U.S. industry (Dumont) "picked up the ball."  On a crash-basis, 125 more sets were soon in supply channels.   Yes, they were warmly received by soldiers far -away whose lives might be saved by that miraculous mortar "blip" showing up on their oscilloscopes.     In closing my story, after later use of the TPQ-3 during the Korean incident, together with its parent TPS-3, these two sets were allowed to enter that Valhalla reserved only for fighting radars-radars which had done their job well; losing only one battle to the Dragon who occupies the Cave of Obsolescence.   But not so my battle-scarred VT-158 . . . its Valhalla will forever be the Smithsonian Institution in Washington, D.C.

Reprinted from SIGNAL, December, 1970
Armed Forces Communications and Electronics Association