Dr. Robert M. Page (1903-1992), Eden Prairie, Minnesota
Retired as Director of Research, U.S. Naval Research Laboratory, 1967.
Dr. Robert M. Page was the original inventor of monopulse radar, having preceded
the work of British scientists by at least nine months (1934). One or two encyclopedias
at least mention him. Most still give credit to Sir Watson Watt (England), especially
where the articles were written by his kin!! Early British developments in radar
used existing ham technology (CW), as they could string wire antennae by the mile
along their coast facing France. They could also separate transmitter and receiver
antennae as required. My dad worked as a junior physicist in the Radio Division
at the U.S. Naval Research Laboratory in Washington D.C.
Earlier experiments by NRL scientists (1922) discovered that ship and plane traffic
along the Potomac River interfered with radio transmissions, but further experiments
with CW transmissions (ham radio technology) proved fruitless for determining range,
bearings, or altitude. Leo C. Young suggested radio pulses. But no one had the technology
to transmit or receive signals in this manner at the time.
My father was assigned the task of inventing something, anything, that might
demonstrate whether this was feasible. He not only succeeded, but quickly went to
high frequencies and high power never dreamed possible in the 1930's to get equipment
small enough and powerful enough to work aboard ships. He used the most powerful
ham radio transmitter tubes of the day (Eimac, Palo Alto, CA) and got 10-20 times
the rated power out of them by designing circuits that turned them on and off for
milliseconds at a time in a 6-tube, sequenced, ring oscillator. The first sea trials
of the XAF were held aboard the U.S.S. Leary in 1937 and allowed range calculations.
The very first test spotted an airplane 45 miles away over the horizon! An improved
200 MHz system was tested on the U.S.S. York in the Caribbean in 1938, with German
submarines known to be about 100 miles away. Three other competing radar systems
were also aboard for testing, all using the same famous XAF "flying bedspring" antenna;
17 ft. x 18 ft., and weighed 1200 lbs. But the transmitter vacuum tubes in the competing
radars kept failing every time the York's big guns were fired. The NRL prototype
kept on functioning, amazing everyone. Nineteen CXAM sets (commercial RCA contract
version) were installed aboard warships in Pearl Harbor when it was attacked on
Sunday, December 7, 1941. Not one was turned on.
See "Tora! Tora! Tora!" for the Army Signal Corps unit on shore and
the rest of that story. From
Bluff overlooking the harbor, trainees Joseph Lockard and George Elliot, saw
the Japanese incoming echoes 15 minutes ahead of the attack and reported them, but
were ignored. Higher command thought the echoes were from an inbound flight of B-17
bombers from Frisco (and with no guns aboard). Too bad. Those are the quirks of
history. George Elliot passed away in December of 2003.
Among his 75 or more patents, Dr. Page was the first to come up with the rotating
display for cathode ray tubes (PPI or
Plan Position Indicator), and the "duplexer" which allowed both transmitter
and receiver to use the same antenna. Imagine standing next to a powerful searchlight
which is turned on for a fraction of a second, after which you are supposed to see
reflections from the sky with your own two eyes. Impossible -- you have just been
blinded for the next 20 to 30 minutes because of the brilliant flash.
This duplexer solution to a vexing problem (blinding and destabilizing a sensitive
receiver) came to my father while in a Sunday morning church service (he apparently
wasn't paying attention to the minister). The idea so impressed him that he stopped
off at the Naval Research Laboratory and recorded the idea into his workshop log
books. His assistant went to work on it immediately; and several days later a working
prototype was installed and tested in a wave guide. It worked the first time. It
took 20 years for other physicists and mathematicians to come up with the correct
explanation for why this device worked as it did.
After the British invented the magnetron, that was combined with the duplexer,
allowing high power and even higher frequency equipment to be installed on board
British fighter-bombers, and just in the nick of time to break the back of the German
wolf packs in the Atlantic. I think it was in May of 1943 that Allied aviation sunk
over 40 German U-boats, and Hitler gave up on that idea. Any time the German subs
came up to the surface to charge their batteries, Allied planes could spot them
even through cloud cover. The submarine commanders carried radio receivers at first,
set to scan radar frequencies. Upon hearing warning signals, they would dive. This
worked against them in two ways. First of all, the Germans received so many signals
from extended distances, that they learned to ignore all but the loudest signals.
Some commanders ordered their receivers turned off, since the false signals were
unnerving to all aboard. As losses increased, the subs were forced to turn their
receivers back on. Only this time, we had developed microwave radar, far beyond
the frequency capability of the U-boat defensive receivers. So subs got caught under
overcasts suddenly and without prior warning, leading to the Black Month of May.
Credit must also be given here to U.S. and British cryptologists who broke the German
communications codes. We knew in advance when subs left on assignments and where
they were headed.
Early in WWII, German scientists tried to get Hitler's permission to work on
the development of microwave radar. When told this might take several years, Hitler
violently refused. His policy required that scientific research produce usable applications
for his military within a year's time. Still German intelligence and scientific
personnel were desperate to discover what the Allies were using. They examined Allied
bomber crashes in detail for radar equipment, hoping to piece together from the
wrecks the secrets of our equipment. As Divine providence would have it, either
the bomber crews or the crashes succeeded in destroying enough evidence so that
it was not until very late in the war that the German technicians came into possession
of more than about half a recoverable microwave radar system. They finally succeeded
however. And Hitler was invited into a tall darkened building in Berlin in late
1943 or early 1944 to see an operating Allied bomber radar system. The screen display
showed a detailed radar street map of Berlin. Perpetuated rumors say this was the
first night Hitler contemplated committing suicide.
My father also pioneered with other groups in the development of fire control
radar, which was responsible for winning several stunning night-time over-the-horizon
naval battles against a numerically superior Japanese fleet in the Pacific.
In another anecdote from the Atlantic, the
HMS Hood was
blown out of the water on May 24, 1941, by the German battleship
Bismarck. It is well known that the Hood only had light armor,
in the interest of speed. So it was ill-designed to engage the Bismarck. Upgrades
were never completed. Not so well known, is the following: Although the Hood fired
first (on the Prinz Eugen, then on the Bismarck), the gunnery officers aboard
the Hood were instructed to cut the range of their guns IN HALF from what their
fire control radars were telling them. The observers on the bridge could NOT BELIEVE
the Bismarck was as far away as their radar said it really was. It was so huge,
they were positive it was much closer then the new-fangled electronics indicated.
When the Hood fired, its first salvos fell into the water half way between the two
ships (9,000 yds instead of the actual 18,000 yds range). The Bismarck then fired
two salvos which bracketed the Hood. Salvo #5 quickly found its target. Whether
the Hood could have caused any substantial damage to the Bismarck is open to debate.
But the Hood could have put her first salvos on the target had she "believed her
instruments." Of additional interest is that the Bismarck had been shadowed the
previous day by the cruisers
The Bismarck fired several salvos of shells at the Norfolk. But the concussions
from those firings put the Bismarck's own search radar, an
FuMO 23, completely out of commission. Oh those pesky,
temperamental vacuum tubes again??? [Recommended reading: the extensive detailed
articles on the Hood and the Bismarck to be found on Wikipedia].
Among other of my father's technical idea contributions was the
MADRE radar system, first installed on the Chesapeake Bay shore.
It was a low-frequency system which followed the curvature of the earth (like ham
radio transmissions), and proved capable of spying on Russian missile firings, by
returning a signal off of the flaming ionized exhaust trail as the missile was launched.
System parameters could be set to determine accuracy of location or accuracy of
velocity, but not both simultaneously. During the experimental development of this
system, a radar installation in Washington D.C. was tracking a weather balloon which
had been launched from a site in Nevada. The electrical signals driving the antenna
servo motors at the Naval Research Lab were observed to be oscillating, as if the
antenna were hunting on an erroneous signal. All circuits were checked and found
to be OK. It was later determined that the radar was attempting to track the oscillations
of a large crumpled-aluminum foil ball which was swinging while suspended inside
the weather balloon. Later functional prototypes of this radar were able to distinguish
differences of velocity among aircraft flying in formation on the other side of
the North American continent; all without benefit of the modern digital computer.
-- I would like to salute several gentlemen who worked under my father, whose
names and contributions will never be known beyond a small circle of people. All
of them are now deceased: Anthony Stecca, LaVern Philpott, Irving Page, Allan Schooley,
Dr. Robert Guthry, and Dr. Leo C. Young. I had the privilege of knowing these dedicated
scientists when I was a small boy. They were all heroes of science, history, and
American freedom. Each was a man of great personal integrity and dedication.
John R. Page, Medford, Oregon