REF ID:A484972 ~RESTRICTED SIGNAL CoRPs BuLLETIN No. 97 · THE SIGNAL CORPS BULLETIN JULY TO SEPTEMBER 1937 WAR DEPARTMENT ----l OFFICE OF THE CHIEF SIGNAL OFFICER .- ' \-~ WASHINGTON, D. C. -6:':' Declassified and approved for release by NSA on 11-13-2013 pursuant to E .0. 1352a REF ID:A484972 ~-....._,,. ,__,.:··--~ . ,~'-· ·.. A l.,•i.,.\J, ..... ::)l.i•· , .. ... ~·--. ,-,r . ','""f ' <. \ ,\ . l.- I I,, • I') 11;, • '" , -""<"'"'w.~c- (1 ·~~.,11~-"'!f ·· THE SIGNAL CORPS BULLETIN \-tU ~ '?) \ July-September 1937 · J P~blished Quarterly by The Chief Signal Officer of the Army CONTENTS• Page L Radio Stations of the Seventh Corps Area ___________________________ _ Staff S&t. Arthur F. Calkins, Sisnal Corps. Radio Frequency Monitoring Station, Fort Omaha, Nebr_______________ 3 StafI Sst. Harold Taylor, Sisnal Corps. Seventh Corps Area Telephone Construction Crew_______ _ __ _ _ _ __ _ _ _ _ _ _ 6 Ray Blain, Telephone Plant Ensineer, S. S. L. Signal Corps Activities at Fort Leavenworth_________ __ _ _ __ _ _ _ _ _ _ _ _ _ _ _ 1.5 Capt. C. W. Clarke, SiAnal Corps. Evolution of the Post Telephone System at Ft. Leavenworth____________ 20 Charles F. Robinson, Electrical Assistant, S. S. L. Duties of the Signal Corps Detachment at an Infantry PosL _ _ _ _ _ _ _ _ _ _ _ 24 Staff Sgt. Leonard A. Jensen, Sisnal Corps. Seventh Corps Area Army Amateur Radio System_____________________ 25 Stall Sgt. James W. Hudgins, SiAnal Corps. A Signal Corps Officer's Experiences in the C. C. C _________________ .- _ _ 30 First Lt. Kirk Buchak, Signal Reserve. Seventh Corps Area C. C. C. Communication_________________________ 31 Capt. R. B. Woolverton, Signal Corps. The Seventh Corps Area Photographic Laboratory_____________________ 33 Pvt. (Ist cl.) C. G. Welcher. An J maginary Letter from a Signal Corps Sergeant. _ ~ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 35 Ray Blain, Telephone Plant Engi'neer, S. S. L. Cipher Busting in the Seventh Corps Area, A. A. R. S _____ - _ _ _ _ _ _ _ _ _ _ _ 37 Col. Stanley L. James, Signal Corps, Signal Officer. Analysis Versus the Probable Word__________________________________ 38 Howell C. Brown, WLVX/W6BPU, Pasadena, Calif. Edgar Allen Poe, Cryptographer_ _____________________________ - ___ - _ 41 Lt. Col. William F. Friedman, Signal Reserve, 0. C. S. 0. The Evolution of Communication___________________________________ 53 Frank V. Rhodes, Consulting Engineer, San Francisco, Calif.,., Reserve Officer Training in the Third Corps Area______________________ 64 Capt. Robert G. Swift, SiAnal Reserve. T-he Battalion Headquarters Company ___________________ - ___ - _ - - __ - _ 67 First Lt. Arthur A. Holmes, Michigan National Guard, Hq. Co., 1st Bn, I:l5th Inf. C. C. C. Radio Communication in the Fourth Corps Area ________ - ___ - .. 70 Capt. D. W. Phillips, Signal Reserve, 16th R. I. Co., Signal OHicer District G. Signal Activities During the 1937 Flood in Southern Illinois ____________ _ 73 Maj. A. V. Eliot, Signal Corps. Curves and Fast Balls at Leavenworth ___________________ - ___ - _ - _ -_ - - 78 Maj. E. D. Cook, Infantry. [ The Editor's Observation Post_ ___________________________________ - _ 82 Future Issues of the Signal Corps Bulletin; ForeiAn Coin­ munication lteins; Radio-Meteorogr:aph System; Radio r Propagation; Ground Constants; Broad-Band Carrier Systems. • Tbio iosue of the Bulletin is devoted primarily to the Seventh Corps Area. REF ID:A484972 j l RADIO STATIONS OF THE SEVENTH CORPS AREA By Staff Sgt. ARTHUR F. CALKINS, Signal Corps The transmitting equipment of radio station WVU is installed in a frame building at the extreme northwest corner of the Fort Omaha Reservation. The transmitters of the A. A. R. S. (Seventh Corps Area) net control station, WLU/W9BNT are also located in this building. l The set used for communicating with station \VAR at \Vashington: D. C., is a ·w estinghouse, 1-kilO\vatt high-frequency transmitter op­ erating on three authorized frequencies, 4305, 8610, and 13290 kilo­ cycles. At the present time most of the traffic is handled on 13290 kilocycles, the other two frequencies being used when and as condi­ tions warrant. A De Forest 2-kilowatt intermediate frequency, and a Signal Corps high-frequency transmitter type BC--185 are used for communicating with corps net stations. The intermediate frequency transmitter operates on 166 kilocycles and the BC--185 on either 4305 or 8610 kilocycles. 147970-37-1 (1) r1~ REF ID:A484972 2 In addition to the above there are three transmitters available for the exclusive use of the Army amateurs. Two of these have been built up locally and operate on the 80 and 160 meter bands, while the third is a commercial transmitter, manufactured by the Lew Brown Co., which operates on 6990 kilocycles. The corps net includes stations: WVC, Fort Leavenworth, Kans.; WZZ, Fort Snelling, Minn.; WUI, Fort Riley, Kans.; WZT, Fort Des Moines, Iowa; WZM, Fort Meade, S. Dak.; and WURC, Fort Lincoln, N. Dak. Fort Snelling, Fort Meade, and Fort Lincoln are all equipped with high-frequency transmitters, while Fort Leavenworth, Fort Riley, and Fort Des Moines make use of inter­ mediate frequency. There are three attendants on duty at the transmitter station, one noncommission~d officer and two privates. The tricks of these men are so arranged as to give continuous service should it be necessary to keep on the air 24 hours daily. That these attendants are efficient is quite evident from the fact that during the past 4 years not one schedule has been missed due to the failure of a transmitter. There have, of course, been interruptions in the radio service but none of them have been due to equipment failures. Only recently a tele­ phone cable which carries the transmitter control and remote re­ ceiving circuits failed and the station was off the air for the greater part of 1 day. Regular inspections, repairs, and adjustments are made each day after the transmitters are shut down. The remote receiving station is located in a brick building at the extreme southeast corner of the Fort Omaha Reservation. The equipment used for receiving consists of three Hammerlund, Comet Pro, short-wave receivers. One of these receivers is kept tuned con­ tinuously on station 'VAR. A second receiver is used for communi­ cating with corps net stations and the third is a "standby", ready for instant use in case either one of the other instruments should fail. The output of these receivers is carried over cable pairs for a dis­ tance of about 5 miles to the Federal Office Building where the messages are actually received. The amateur system makes use of the "standby" receiver when necessary. The second Hammerlund is also available for amateur use when the corps net is clear. Three men, a noncommissioned officer and two privates, are on duty at the remote receiving station. The noncommissioned officer takes the readings of the frequency monitor and the other two attendants split tricks tuning and monitoring the remote receivers. The main receiving station is located near the corps area signal office on the tenth floor of the new Federal Office Building, Fifteenth and Dodge Streets, Omaha, Nebr. The equipment now being used consists of two Signal Corps radio receivers type BC-197, one REF ID:A484972 3 Hammerlund, Comet Pro, and one RCA model 136, short-wave receiver. The intermediate frequency receivers are used for communicating with the corps net stations which use inter­ l mediate frequency and the two short wave receivers are used when­ 1 ; ever practicable to work with WAR or corps net short-wave stations. ---! The location of the receivers, in the center of the city, makes short­ wave reception during the daylight hours extremely difficult due to jnterference from nearby electrical apparatus. An effort was made to clear this interference and operate without the necessity of using remote receivers but the city authorities were unable to approve the necessary ordinances to control the interference. The personnel on duty at the receiving station are: Chief operator, message center chief, message center clerk, and five radio operators. Tricks are so arranged as to have two radio operators on duty from 7 a. m. to 1 p. m., and three from 1 p. m. until clear. The Western Union and Postal Telegraph Co. both maintain teletype printers in the receiving station. All radio men on duty in the station are competent teletype operators. RADIO FREQUENCY MONITORING STATION, FORT OMAHA, NEBR. By Staff Sgt. HAROLD TAYLOR, Signal Corps The following equipment is now in use at the frequency monitor located at Fort Omaha, Nebr.: A primary standard consisting of a timing unit, type 593; a 1 kilocycle multivibrator, type 592; a 10 kilocycle multi vibrator, type 592; a temperature control unit, type 591; a heat control unit, type 594; an alternating current power sup­ ply unit, type 595; a secondary standard consisting of an interpola­ tion oscillator, type 617-B; a heterodyne frequency meter, type GR-P-351; a heterodyne detector, type GR-P-303; a three-stage resistance coupled amplifier, type GR-X-173; and an alternating current power supply, type 595. (All equipment by General Radio.) The temperator control unit, type 591, contains a 50-kilocycle quartz crystal and oscillator circuit, an enclosing asbestos-lined alu­ minum oven with heating pad and thermostat, a second aluminum oven similar to the first and enclosing it with a dead-air space be­ t tween, and an all-enclosing balsa-wood case. This arrangement, with I the coordination of the heat control unit, type 594, which contains relays and rheostats for regulating current through the heater pads, maintains the temperature of the crystal to within 0.01° C.