From:      Commanding Officer
To  :      Chief of Naval Operations.
           (Communication Security Section)
Via:       The Commandant, 13th Naval District.
Subject:   Radio Intelligence Report for the month ending
           31 December 1941.

      1.   There is forwarded herewith the report of Radio Intelligence Activities of this station for the month ending 31 December 1941, consisting of the following sections:

     At the beginning of December we had the Trans-Pacific telephone circuits (San Francisco-Tokyo) to cover both ways, broadcast schedules and regular International Diplomatic circuit assignments.

     On 3 December we received a directive to cover San Francisco International circuits to Tokyo in addition to regular assignments and to forward all plain language Japanese government traffic (in addition to those codes already being sent) to WA91 via TWX.

     On 6 December OP-20-GX directed that codes having LA as first two characters of text and whose text was made up of consonant-vowel combinations need not be forwarded by TWX.

     Diplomatic traffic was very heavy on International circuits from 4 to 6 December inclusive.

     On 7 December on local midwatch (zone plus eight) Tokyo sent to Japanese government messages addressed to KOSHI WASHINGTON which he labeled in a service message to San Francisco operator as being very important. Tokyo placed these two messages on both RCA and MRT circuits with same service message. These two messages were sent from Station S to WA91 immediately with the words "very important" in the heading (see our TWX number 380 and 381 on 7 December).

     On 7 December war began between US and Japan by Japan's attack on Pearl Harbor.

     On 7 December a three-section watch was placed into effect with men from the off section filling in during peak periods. It was necessary to recall three of the six men who had started the Kana class to augment the watch. It has also been necessary to use the other three men from the Kana class during peak periods to prevent too much delay in forwarding TWX traffic to WA91. This has usually been for only two or three hours at a time and has caused no one to lose out with the rest of the class.

     On 7 December OP-20-GX directed the discontinuance of monitoring of the San Francisco-Tokyo Trans-Pacific telephone circuits and the discontinuance of monitoring of the "MAM" schedule unless desired locally.

     On 8 December HAFU6 (Tokyo Navy Radio) was noticed using 17.4 Kos for delivery of Navy traffic by F method to the following four calls: KI NI 0, KA RI 8, SA TA 4, and FU KE 3. This frequency was formerly used by JND (Nagoya) to work European stations and has a listed power of 550 KW. As this was not an assignment of ours we sent sample messages to OP-20-GX via TWK and asked if it was desired that this frequency be covered by Station S. We were directed to continue covering but to send traffic thus obtained via air mail. On one occasion JNL (Nagoya) tried to use this transmitter to work Berlin but confusion resulted and JNL discontinued. Since 8 December we have copied 3600 sheets of traffic from HAFU6 on this frequency.

     On International circuits Tokyo continued to call San Francisco for some three days and even sent some government traffic blind. We intercepted this but it is not known whether San Francisco copied or forwarded it. San Francisco made no reply after the 7th.

     Mexico did not break communications with Tokyo but according to a plain language message (6081) required that all Japanese government traffic be filed in either plain language English or plain language Spanish. However, very little traffic of any kind (government or commercial) has been handled between these two countries since the outbreak of war.

     Other International circuits are normal except for slightly heavier volume of government traffic.

     Since the outbreak of war we have been covering all Tokyo International channels possible and forwarding government traffic thus obtained via TWX. During slack periods operators research for Orange Navy frequencies and give frequencies and calls heard to DF organization for bearings.

     On 10 December a message was received from OPNAV through COM13 directing that highest priority be given all Orange assignments and to send all Orange government traffic by TWX immediately. The message further directed that all Orange plain language broadcasts be copied but send via TWX only those broadcasts having the word "stop" as last stop.

     Since the outbreak of war the broadcast schedules have been increased in both number and in length. Now there are broadcasts even in Spanish and French (see International message #6826). These schedules start every half hour from 0700 to 0200 Japan Standard time (2200 to 1700 GCT). We can cover these from 2200 GCT to about 0700 GCT; then they are unheard until 1100 GCT from which time we get good copy until secured about 1700 GCT. These schedules now run practically full time; that is, from 25 to 30 minutes each half hour. When the schedule goes into effect on 4 January 1942 this material will go out on different frequencies with different matrial at the same time thus necessitating more than one man to cover. OP-20-GX has been requested to confirm this assignment in the light of the increased volume and time necessary to cover.

     On 16 December on the 2330 (GCT) schedule on JVJ/JUD (12275/15880) the following was repeated 45 times: "HOSO NASI 0830." This translates: "No broadcast at 0830." But with the possibility that this might be a signal of some kind it was reported to COM13 for transmittal to OPNAV in accordance with OPNAV Letter Serial 040720 of 16 Janurary 1941.

     On 26 December OP-20-GX Memo dated 20 December 1941 directing use of authenticators between Station S and WA91 was received and was placed into effect on 1 January 1942.

MATERIAL

     Two Reference Recorders, type P2, Model C, dual units, and one portable recorder, Model P2, type c, Mfd by Frank Riaber, Inc., Los Angelos, Calif., were received. The latter is a single unit, primarily for transcription service but can be used for recording if desired.

CALLS AND ADDRESSES

     There were no new calls and addresses or signatures noted during December.

     On December 3, we received a directive from OP-20-gx to forward by teletype Orange government traffic addressed to Tokyo and signed by the Japanese Minister in Washington. In order to receive this traffic it was necessesary to monitor all San Francisco channels, both RCA and MRT.

     The winter frequencies employed by these stations are received at "S" with indifferent success. Since our two Ediphone equipments were employed on voice circuits (Tokyo-San Francisco and San Fancisco-Tokyo), we were deprived of that method of reception.

     By December 6th we had researched the SF-NY and NY-SF channels, both RCA and MRT, and were receiving solid copy of all Washington traffic sent via New York. These circuits might prove to be of value in the future, and are therefore listed below

MACKAY RADIO CIRCUITS
New York to San Francisco
	Night	WKT7	5985	Kilocycles
	Day	WAE	15675	"
San Francisco to New York
	Night	KNA9	5315	"
	Day	KJA	10570	"	(Used both day and night)
	Day	KWP	15535	"
RCA RADIO CIRCUITS
New York to San Francisco
	Night	WDG	4535	"
	Night	WEP	5190	"
	Day	WEZ	8075	"	(Used both day and night)
	Day	WQT	13885	"
San Francisco to New York
	Night	KEG	5110	"
	Night	KEN	6845	"
	Day	KKZ	13690	"
	Day	KKR	15460	"
	Day	KKL	15475	"

Washington to New York RCA circuits are WQEX (2776 kc), WQEN (5105 kc) and WQEO (6852 kc) but were not observed here.

     It was intereting to note that on the afternoon of December 7th, the Supervisor New York instructed the Supervisor San Francisco (RCA) to stall on the job with reference to Tokyo circuits.

CHANNELS LOST AND GAINED

     On December 7th BATAVIA-TOKYO did not meet for their 2330 GCT schedule and have not resumed communications.

     On December 8th TOKYO-BANGKOK and TOKYO-SAIGON failed to show.

     On December 10th TOKYO-BANGKOK resumed communication but TOKYO-SAIGON remained dark.

     On December 15th SAIGON-TOKYO resumed communication but SAIGON (FZG3-10,825 kcs) normally employed to TOKYO remains dark, since the 7th.

     SAIGON now uses the following frequencies to TOKYO:

FZS3 - 9,485 kcs
FZS4 - 11,785 kcs (M)
FZS5 - 11,750 kcs (A)

     During the above period a continuous searching watch was maintained at the Net COntrol and Plotting Center on Bainbridge Island on the calling and working frequencies used by Orange Merchant Vessels. Each station on the Net conducted its own search and took bearings on transmission smade by Orange Merchant Vessels when transmissions were heard on prescribed schedule of frequencies. The Schedule was

     Stations of the Net forwarded their bearings to Plotting Center at 0000 and 1400 GCT daily via despatch. All bearings reported by stations of the Net were logged and fixes plotted of ships' positions, when possible, from bearings obtained from two or more stations when taken at or approximately the same time.
     Good fixes on Orange Merchant Vessels, obtained by plotting reliable bearings obtained from three or more stations of the Net, were reported in CONFIDENTIAL CODE to the Chief of Naval Operations and the Commandants of the Twelfth, Thirteenth, and Fourteenth Naval Districts. Included in these reports were any intercepted position reports from Orange Merchant Vessels that had been intercepted.

     In accordance with instructions received from the Chief of Naval Operations (OP-20-G) a weekly summary of all High Frequency Direction Finder bearings obtained on Orange Merchant Vessels by the West Coast Strategical High Frequency Direction Finder Net was forwarded to the Chief of Naval Operations (OP-20-G) and the Commandants of the Twelfth, Thirteenth, and Fourteenth Naval Districts. This weekly summary of bearings, tabulated daily, consisted of
The Name of the Orange Merchant Vessel
Radio Call Sign
Stations of the Net obtaining bearings
Bearings, and time taken
The estimated D/F position, and
remarks.

     As the general trend of movements of Orange Merchant Vessels was towards the Western Pacific and, so far as could be determined, only three Orange Merchant Vessels were in the Pacifc, East of the 180th Meridian, no positions were plotted during this period due to lack of bearings.

     The weekly report of High Frequency Direction Finder bearings taken on fixed sations as directed by OP-20-G Restricted Serial 48920 JJ 16/L5-2 (410715) of 15 July, 1941 was cancelled on 7 December, 1941, therefore no report was forwarded after the report for week ending 6 December, 1941.

     At 0555 GCT 7 December, 1941, the Net, with exception of SITKA which remained on Orange Merchant Vessel Assignment, was placed on 4385 kcs for ferry plane flight. This special assignment remained effective until 1927 GcT of 7 December, 1941 when the net was ordered to cover Orange Naval Frequencies.

     At 1940 GCT on 7 December, 1941 all stations of the net were placed on WAR BASIS with instructions to cover Orange Naval Frequencies and immediatel report all bearings obtained to Control and Plotting Center.
     All mainland stations of the Net, Point St. George and Imperial Beach were directed to maintain 24 hour service with the Net Control Station at Bainbridge Island via TWX. The communication office at San Francisco was also directed to maintain similar service to expedite service between Farallon Island and Bainbridge Island.
     The method used in obtaining rapid results between Net Control and stations of the Net was:
   (1)The search operator at Net Control Station on hearing an Orange Naval transmission and having properly tuned the signal would immediately
   (2)Place on the TWX the call sign of the transmitting station, if the call sign had been determined

     All bearings reported by stations of the net were logged and fixes plotted of ship's positions, when possible, from bearings obtained from two or more stations when taken at or approximately the same time.

     Good fixes on Orange Merchant vessels obtained by plotting reliable bearings from three or more stations of the Net were reported in confidential code despatches to the Chief of Naval Operations and the Commandants of the Twelfth, Thirteenth, and Fourteenth Naval Districts. Included in this report were any intercepted position reports from Orange Merchant Vessels received since last report of previous day.

     In accordance with instructions received from the Chief of Naval Operations (OP-20-G) a weekly summary of high frequency direction finder bearings obtained on Orange Merchant Vessels by the West Coast Strategical High Frequency Direction Finder Net is forwarded to the Chief of Naval Operations (OP-20-G) and the Commandants of the Twelfth, Thirteenth, and Fourteenth Naval Districts.

     The weekly summary of bearings tabulated daily consists of the names of the Orange Merchant vessels, radio call sign, stations of the Net obtaining bearings, bearing obtained, the estimated D/F position, and remarks.

     The following list shows the Orange Merchant vessels and dates on which two or more stations of the net obtained bearings at or approximately the same time. These bearings were plotted by the Net Control and Plotting Station to determine a D/F fix for tracking. Further information is shown by listing the frequencies used by each Orange Merchant vessel and the ship or station communicated with.

     All direction finder position fixes of Orange Merchant vessels are plotted on separate charts. A total of 21 Orange Merchant vessels were tracked during the month of November, 1941.

     Movement reports of Orange Merchant vessels received from the Office of Naval Intelligence and the District Intelligence Officer of the Thirteenth Naval District as well as intercepted position reports are entered in a card index file, arranged alphabetically by call sign, for comparison and reference with direction finder tracking.

     High frequency direction finder bearings recevied via the Commandant Thirteenth Naval District from the Canadian High Frequency Direction Finder Stations at GORDON HEAD and UCLUELET on Orange Merchant vessels were used for separate plotting with the bearings obtained by the West Coast net and for separate records.

     A daily average of Orange Merchant vessels positions plotted by the Net Control and Plotting Center at Bainbridge Island was five while a daily average of eight bearings were taken by Bainbridge Island Direction Finder Station on five different Orange Merchant vessels during the month of November, 1941.

     As the general trend of movements of Orange Merchant vessels is toward the Western Pacific and seven of the vessels which were in the Eastern Pacific during the first few days of November had arrived in Japanese ports the number of positions plotted during the period 16 to 30 November was less than one third the total number plotted during the month. So far as can be determined only three Orange Merchant vessels are now in the Pacific, east of the 180th Meridian, TERUKAWA MARU, proceeding northwest from the West Coast of South America; NARUTO MARU, prodeeding northward along the coast of South America and the TOA MARU in the South Pacific and due at a Japanese Port in early December, 1941.

     No other special assignments were conducted by the Net during November, 1941.