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by Ronald Russell
(The following originally appeared
in Veterans Biographies, distributed during the annual Battle of Midway
commemoration in San Francisco, June 2006)
Upon graduation from high school in 1941, Phil Jacobsen
knew that he wanted a career in radio electronics, but there was no money in
his family for college. He turned to
the Navy as a training resource, and succeeded in getting into radio school
after boot camp. Freshly trained in
radio operation, equipment maintenance, and message handling procedures, his
class was sent to Pearl Harbor where the Navy decided the new radiomen could
best serve as laborers at the ammunition depot! Jacobsen and several others were rescued from that drudgery when
CDR Joseph Rochefort, in charge of the Combat Intelligence Unit at Pearl
Harbor, directed the expansion of Japanese intercept operator training to
support his growing cryptologic operation.
The new intercept operators were
trained at Wahiawa, in the center of Oahu.
They were immediately immersed in learning the 48-character Japanese
equivalent of Morse code, as well as both the katakana and romaji variants
of written Japanese. In time they
became proficient on a special typewriter that printed romaji characters,
and were also taught Japanese communications procedures, message formats, and
operating signals. The also learned
radio direction finding techniques.
By May of 1942, RM3/c Jacobsen had
completed training and was standing watches at radio intercept “Station H” at
Wahiawa. The operators were informed of the possibility of a forthcoming
large-scale Japanese operation, and to be extremely alert for any unusual
activity or ship’s movements. Enemy
message traffic gradually increased in level as the month progressed giving a
further clue to the radiomen that something big was in the wind. Jacobsen recalls seeing the officer in
charge at Station H and his chief radioman examining a chart with two tracks of
ships converging on Midway.
The skills practiced by RM3/c
Jacobsen and his comrades at Wahiawa during that time provided a vast quantity
of remarkably clear raw material for CDR Rochefort’s cryptanalysts at the
Combat Intelligence Unit. There the
Japanese signals were decrypted and analyzed, leading to an extraordinary
understanding of the Imperial Japanese Navy’s intentions at Midway weeks in
advance of the attack. That enabled
Admiral Nimitz to plan what was to become the greatest American naval victory
of all time. There are many reasons for
the triumph at Midway, principally centered on the incredible bravery of the
men manning the guns and flying the planes as the battle raged. But the success achieved there started with
a few enlisted radiomen capturing the intelligence from the airwaves that made
the victory possible.
Late in 1942, Jacobsen transferred
to Guadalcanal with a team that established a new radio intercept and
cryptologic unit there as the battle for the Solomon Islands raged, and he served
at other Pacific sites as the march toward Japan continued. He retired from the Navy in 1969 after 28
years of service, nearly all in communications intelligence.
Navy Cryptology
at the Battle of Midway: Our Finest Hour (More about the communications intelligence victory at Midway,
by Phil Jacobsen)
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