Communications Intelligence Summary, 17 November, 1941
General.-Traffic volume normal with receiving conditions good. More traffic with single call heading appeared on
the broadcast circuit. These dispatches
numbered serially and each call different but all fitting the same line in the call garble table. Since these
messages are transmitted each hour on
the hour and are of approximately the same length it appears that they are drill messages. It is feared that
they constitute a test of straight
broadcasting without a heading. Since none of this traffic has been found going in to Tokyo it is
probably originated in the Navy Ministry. Very few messages of general
address were noted. Tactical circuits
in the Mandates were heard during the day with radio Saipan controlling.
Combined Fleet.-No movement from the Kure area of any major portion of the First or Second Fleets. The CinC. Second
Fleet very active as an originator
today. He continues to address units which are most normally under his command. He also addressed the
CinC. Third Fleet, Paloa Forces, and
the Chief of Staff Fourth Fleet.
Third Fleet.-Inactive at Sasebo. The Staff Communication Officer of Third Fleet was addressed by the R. N. O.
Fourth Fleet.-The greater part of the activity in the Mandate area centered about the Third Base Force at Palao
and the Sixth Base Force at Jaluit.
Both these activities originated traffic.
Air.-The Commander of the Combined Air Force remains in Takao and was addressed frequently by SAMA, HAINAN and was
in two instances addressed by the
Fourth Fleet. The carriers are mostly in the Kure-Sasebo area with the exception of a few which are
operating in the Kyushu area.
China.-Sama was again active today with dispatches to the Combined
Fleet Staff, Combined Air Force, Third
Fleet and Bako. The R. N. O. Taimoku addressed
a dispatch to CinC. China, Sanchow Island Sama, Bako, CinC. South China, and Chief of Staff Combined Air
U.S. CONGRESS JOINT COMMITTEE ON PEARL HARBOR ATTACK HEARINGS; PT. 35, THE CLAUSEN INVESTIGATION, PP. 62-81.
EXHIBIT "A" DAILY COMMUNICATION INTELLIGENCE SUMMARIES)