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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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