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||George H. Clark Radioana Collection
c. 1880 - 1950
By Robert S. Harding, 1990
Revised by Robert S. Harding, 2001
Archives Center, National Museum of American History, Smithsonian Institution
© 2001 by the Smithsonian Institution. All rights reserved.
NUMBERED SERIES DESCRIPTIONS 1-50
Go to Numbered Series Descriptions 51-100, 101-150, 151-233; Lettered Series Descriptions
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Series 1: LIBRARY OPERATING SYSTEM, 1915-1950 (Boxes 1-3)
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This series contains cataloging information on apparatus in the RCA Museum begun by Clark in 1928, including a general description of objects; information about the classification system Clark devised for his "Radioana" collection, including U.S. Navy WWI Classification system; and information on the history of the collection.
Series 2: APPARATUS TYPE NUMBERS, 1916-1931 (Boxes 4-5 )
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This series consists of a memorandum from Clark to RCA and GE recommending the adoption of the Government's type number system for all American radio companies, and specifically recommending the Navy type numbering system.
Series 3: PHOTOGRAPHIC LISTS, 1925-1928 (Box 6)
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This series contains lists, by number, of photographs in the files of Thomas Coke Knight, New York City (see Series A). It also includes lists of other photographs, e.g. RCA and the Marconi Company; Jenkins Television System, manufactured at De Forest factories at Passaic and Jersey City, New Jersey, 1925 - 1928; negative numbers with some captions for the RCA Radio Show Display, "The Wooden Book of Radio" and the duplicate of a bound book in series 14 containing photographs of the display; and a notebook, titled "Fessenden" containing photographic captions and numbers for the National Electric Signaling Company, Brant Rock, Massachusetts.
Series 4: BIOGRAPHIES OF RADIO PERSONAGES, TECHNICAL,1898-1948 (Boxes 7-36)
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This series comprises a large collection of disparate materials accumulated by Clark on persons important in the technological development of radio. Included in it are primary materials relating to some of the most important inventors and innovators in radio and wireless communication, including Guglielmo Marconi, Lee DeForest, Nicola Tesla, Reginald A. Fessenden, Roy A. Weagant and John Stone Stone. Additionally, Clark collected documentation on amateurs, radio corporation executives, navy radio aids Clark knew, operators, engineers and hundreds of others active in radio in the first half of the twentieth century. The documents include: letters, and in some cases, full sets of correspondence between individuals; biographical and autobiographical writings (such as resumes) solicited by Clark for inclusion in his "radio library"; writings by Clark and others on various topics in radio history; litigation and patent documents; internal corporate memoranda; drawings, blueprints and designs; and most voluminous, printed material in various forms, including clippings, articles, award programs, press releases and scrapbook entries. Clark's scrapbook entries range from one-line facts about individuals typed or written directly onto a page, citations for other sources of information about individuals, business cards, photographs, and newspaper and magazine clippings ranging in length from one or two lines to several pages.
This series is arranged in alphabetical order by name of individual. The box and folder inventory of this finding aid indicates what types of documents are included on each person. A separate file has been created for individuals when primary material is included. When only secondary material exists, such as clippings, the material has been filed in a general file under the appropriate letter of the alphabet. The finding aid also lists these names and types of documents included. Photocopies of scrapbook items have been filed in cases where information about more than one individual was found on a single page. Correspondence and other documents which pertain to more than one person have been cross referenced in the index to correspondents which follows this finding aid.
A selected list of individuals for whom the collection contains the most comprehensive primary material follows: Armstrong, Edwin Howard; Clark, George H.; DeForest, Lee; Dolbear, Amos; Dubilier, William; Dunlap, Orrin; Fabbri, Alessandro; Farnsworth, Philip; Fessenden, Reginald A.; Firth, John A.; Goldsmith, Alfred N.; Harbord, James G.; Hooper, Stanford C.; Isbell, Arthur A.; Kintner, S.M.; Logwood, Charles Vern; Loomis, Mahlon; Lowenstein, Fritz; Marconi, Guglielmo; Mauborgne, Joseph O.; McCandless, H.W.; Nally, E.J.; Oleson, Harold F.; Pickard, Greenleaf Whittier; Sarnoff, David; Stone, John Stone; Weagant, Roy A.
This series was processed by Cathy Keene, May, 2000
Series 5: HISTORY OF RADIO COMPANIES, 1895-1950 (Boxes 37-126)
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This series consists of records organized by company and thereunder generally in chronological order. The material includes correspondence, memoranda, reports, lists of captions, news clippings, patents, news releases, bulletins, legal papers and other papers and records of various radio companies. This historical data gives insight into the inception, growth and activities of the companies. Boxes 37-99 consist of records organized by company and thereunder generally in chronological order. Boxes 100-126 consist of records from a variety of sources numbered serially but not otherwise arranged. This control file in the repository includes folder listings for most boxes.
This series does not include data on radio broadcasting stations. This may be found in Series 8. See Series 14 for the general history of the growth of radio. See Series L for index to photographs in Bound Volumes.
Series 6: SHORE STATIONS, 1900-1940 (Boxes 127-136)
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This series contains biographies of individuals associated with shore stations, including Lieutenant A. Fabbri, U.S.N.R.F.; blueprints; Brant Rock Notes (2 volumes); correspondence; descriptions and photographs of early wireless stations; diaries; data; drawings; engineer's logs; histories; invoices; maps; news clippings; notes; photographs, including some of RCA Radio Pageant, 1929; postcards; public news reports; receipts; signal reports; specifications; telegram forms from commercial and government shore stations for trans oceanic communication and for communication between shore stations. The shore stations include Astoria, Colon, Ketchikan, and Tuckerton. A list of shore stations can be found in series 109.
This series does not include stations for marine or aircraft communications, either on shore or afloat, or broadcasting, television, and amateur stations. See Series L for index to photographs in Bound Volumes.
Series 7: MARINE RADIO STATIONS, 1900-1930s (Box 137)
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This series contains a catalog of "Marine Coastal stations of RCA and Typical Marine Equipment"; correspondence 1911-1924, 1931, 1935; diagrams; drawings; inventories; list of stations ashore by company, May, 1915; news clippings; news releases; photographs, including RCA Radio Pageant, 1929; radiograms; RCA Radio Telegraph Transmitter catalogs; and ships position reports of commercial and government marine radio stations both ashore and afloat. The offshore stations include the S.S. Arkansas, S.S. Atlanta, U.S.S. Connecticut, S.S. Leviathan, S.S. Mauratania, and U.S.S. Philadelphia.
This class does not include aircraft communication stations. A list of stations is in Series 109.
Series 8: BROADCASTING STATIONS, 1910s-1940s (Boxes 138-139)
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This series contains articles; booklets; catalogs; correspondence; descriptions of stations and equipment; extracts; histories; newspaper and magazine clippings; notes; pamphlets; photographs; postcards; releases; RCA Radio Pageant, 1929; statistics; and summaries of data about specific broadcast stations, AM and FM, and about broadcasting studios. This series includes information about government and commercial stations, lists of which are in Series 109.
Series 9: AMATEUR STATIONS, 1910s-1940s (Box 139)
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This series contains articles from Radio News, Radio Condenser, and QST, a magazine devoted exclusively to the wireless amateur; a book, Practical Wireless Amateur Stations; news clippings; photographic illustrations of amateur stations and "set-ups"; and a radiogram to Clark, 1933. Lists of stations are in Series 109.
Series 10: MISCELLANEOUS INFORMATION, 1911-1914 (Box 140)
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Miscellaneous materials which Clark did not place in other classifications ( or Series) he included in this Series including advertisements: including one for an RCA Victor tie clasp; articles; building plans; panel from a Marconi cigar box; correspondence; essays on wireless; examination by Clark, 1939; "Postage Stamp Containing Direct or Indirect Reference to Radio Communication"; maps (Works Progress Administration Employment, October, 1936); news clippings; news releases; photographs; reports. The series also holds seven booklets, including the "Official Handbook of [the] Panama Canal", 1913, and a photographically illustrated booklet about the Panama Canal, compliments of the United Fruit Company and Steamship Service, with views of the Canal under construction and a map of the Canal Zone.
Series 11: RADIO ANTIQUES, 1920-1938 (Box 141)
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This series includes Wireless Age, 1920 -1924, Volumes 8 & 11; Shuart, G. W., Radio Amateur Course, 1938; and Grainger, J., Amateur Radio, 1922.
Series 12: This series number, along with some other numbered series that follow, is not represented in the original classification system developed by Clark.
See Series I (eye): MISCELLANEOUS SERIES, 1899-1949 (Boxes 504-505) for a list that the archivist has placed together of thirty five miscellaneous small series. These small series consist of one folder each.
Series 13: SPECIFICATIONS, 1910s-1930s (Boxes 142-144)
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This series contains specifications of the United States Navy, Army, and commercial companies for all types of radio apparatus, including condenser racks; continuous wave radio transmitting equipment; loop radio receivers; Marconi vacuum tubes; Moorehead tubes; radio communication apparatus; D.C. and A.C. volt meters, D.C. and A.C. ammeters, Wattmeters, Ampere Hour meters, radio frequency ammeters; radio direction finders; switchboard instruments and appliances; transmitting condensers; and transmitting vacuum tubes. Also included are drawings, index sheets of series of blueprints, and memoranda regarding specifications.
Series 14: GENERAL HISTORY, 1899-1950s (Boxes 145-148)
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This series contains material on the history of the radio in general, consisting of abstracts of manuscripts, reports, and printed works; addresses; articles; autobiographies; booklets; correspondence; clippings from journals; diagrams; histories; lectures; memoranda; notes; pamphlets; photographs; releases; reports; reviews; sketches for notes; statements; talks; and portions of yearbooks.
Series 15: RADIO COMPANY CATALOGUES & BOUND ADVERTISEMENTS, 1873-1941 (Boxes 149-1950)
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This Series contains catalogues and other advertisements from many companies for a variety of related products e.g. batteries, tubes, and ear phones. Advertisements for broadcast receivers are in Series 45.
Series 16: LOG BOOKS, 1902-1923 (Boxes 151-161)
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This series contains log books compiled by early wireless workers between 1907 and 1919. Also included is an unused bound amateur log book. The authors of the books are not identified in most cases. The logs record various tests and experiments with radio equipment.
Series 17: RADIO COMPANY'S HOUSE ORGANS, 1896-1942 (Box 162)
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This series contains some correspondence, 1935-37 & 1941, to and from Clark and other executives regarding company house organs; a report on the possible issue of an RCA house organ; and copies of various house organs, including the following:
This class does not include yearbooks or proceedings of radio societies. See Series 145.
- Allerton House Magazine, 1929
- Amrad (The Voice of the Air), 1922-1923
- De Forest Ourselves, 1929
- Federal Flashes, 1920
- General Electric News, 1939
- Over the Soldering Iron, 1934 (RCA)
- Photophonews, 1932, 1931
- RCA Key-Clicks, 1938
- Sales and Service, 1938 (RCA Photophone Ltd.)
- Telegraph and Telephone Age, 1936
- The Aerovox (research Worker), 1928
- The Andion (DeForest), 1929
- The Grid (DeForest Radio Co.), 1929
- The Marconi Review, 1936
- The RMA News, 1928, 1929
- The Radiotron News (RCA), 1929, 1930
- The Voice of the Victor, 1930, 1911
- Wireless News, 1903
Series 18: PRIME MOVERS, 1904-1911 (Box 162)
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This series consists of photographs of Prime Movers and instructions for the care and preparation of motor boat gas engines. Included are several photographs of Curtis Turbine sets; photographs of alternating current generators for wireless telegraphy; internal combustion and steam engines and air driven generators; specifications for Hornsby Akroyd oil engine, 1904; blueprints of several engine diagrams; directions for engine operations; and descriptions of wireless telegraphy powered by steam turbines.
Series 19: BATTERIES, 1898-1934 (Box 163)
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This series contains data and photographs regarding both storage and dry type batteries; notes; memoranda; correspondence; magazine and newspaper clippings; bulletins of RCA Institutes, Inc., School of Communication; blueprints and drawings; abstracts from Naval Radio Monthly Report; Bulletins of the Edison Storage Battery Co.; instructions for changing and operating batteries; and notes on acceptance, inspection, installation, charging and discharging, maintenance, and trouble with batteries.
Series 20: RECTIFICATIONS, 1875-1935 (Box 163)
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This series contains newspaper and magazine clippings, articles, correspondence, pamphlets and booklets, about rectifiers; several copies of "Descriptive Specifications for Rectox Rectifiers," instructions for installation and operation; and Department of Commerce and Labor, Bureau of Standards, publication titled "Some Contact Rectifiers of Electric Currents."
The series includes Mercury type, Mechanical Thermionic-electric, and Dry, contact type, but does not include tubes for electronic types.
Series 21: MOTOR GENERATORS, 1898-1936 (Box 164)
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This series contains information on motor generators and hand generators, including newspaper clippings on gasoline generators; diagrams and graphs; standard descriptive data and tests for motor-generator sets; correspondence; reports and directions on use of lead covered conductors; specifications of high tension direct current generator sets; specifications of steam turbines and alternators; and photographs.
Series 22: NAMEPLATES OF APPARATUS, 1928 (Box 164)
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This series consists of nameplates of apparatus assigned by RCA; badges of radio companies; badges of radio inspectors, and radio aides; pins, rings, and other insignia of radio societies and radio companies; included are drawings, diagrams, nameplate instructions, correspondence and memoranda of RCA officials, 1928 regarding nameplates on apparatus manufactured by RCA, diagrams of nameplates, and an explanation of RCA model designations.
Series 23: SWITCHBOARDS AND SWITCHBOARD INSTRUMENTS, 1910-1935 (Box 165)
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This series contains advertisements; articles; correspondence, 1911 - 1933, including a letter to Philo Farnsworth with a file history on Andrew Plecher's patent no. 187,664; diagrams; minutes; photographs of radio switchboards and instruments; reports, including a printed report by G.E. on field rheostats, 1914; and specifications for: Panel and frame; Switches; Voltmeters and other meters; Frequency meters (power frequency); relays (except relay keys); Solenoid switches (as part of the panel); Field rheostats (as part of the panel); Motor generator transfer switch (when not an integral part of the motor starter); Transformer transfer switch; and fuses, clips, and terminals.
Series 24: RADIO FREQUENCY SWITCHES, 1905-1933 (Box 165)
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This series contains information about radio frequency switches; Fessenden send-receive switch "walking beam" type; American Marconi antenna transfer switch; and Stone Telephone and Telegraph Co. antenna send-receive switch. Also included are records and drawings of antenna transfer switches produced by the De Forest Co., the Wireless Specialty Apparatus Co., and the Liberty Electric Corporation. There is also correspondence to and from George H. Clark regarding this technology.
Series 25: TRANSMITTER TRANSFORMERS, 1893-1949 (Box 165)
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This series contains abstracts; advertisements; articles; clippings; correspondence (1910); descriptions of transformers; diagrams; photographs; reports; sketches; and specifications for transmitter transformers, particularly for spark transmitters. This material covers high and low tension reactances and built-in transformer choke coils (when external these are listed as "protective devices").
Series 26: OPERATING KEYS, 1843-1949 (Box 166)
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This series consists of photographs; blueprints; reports; general data; drawings; descriptions; main sending key; relay keys, such as the Massie relay key; combined hand and relay key; relay control key; resistances, reactances, aluminum cells, etc. to reduce sparking at key contacts; and sample of tape perforated by Kleinschmidt perforator for use with the high speed automatic transmitter.
Series 27: POWER TYPE INTERRUPTERS, 1902-1938 (Box 166)
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This series contains advertisements; articles; correspondence, 1909 and 1941; descriptions; and illustrations concerning power type interrupters, particularly Chopper (for arc transmitters) Mechanical, Mercury Turbine, and Wehnelt.
Series 28: PROTECTIVE DEVICES, 1910-1925 (Box 167)
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This series contains advertisements; articles; blueprints; booklets; correspondence, 1915-1917; diagrams; and reports, such as the "History of Protective Devices," 1919.
Series 30: MESSAGE BLANKS, 1908-1938 (Box 167)
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This series contains message blanks for radio communication including aerograms; Marconigrams; Photo Radio Receiving blanks; postal cards; radiograms; and wireless press sheets. The following companies or agencies are represented:
- American De Forest Wireless Telegraph Co.
- Amalgamated Wireless (Australasia) Ltd.
- Companhia Radio Telegraphica Brasileira
- Continental Wireless Telephone and Telegraph
- Chinese Government Radio Administration
- Fessenden Wireless Service, NESCO
- French Radio Co.
- Globe Wireless Ltd.
- Great Northern Telegraph Co. (Hong Kong)
- Holland Radio
- Imperial Japanese Telegraph
- Israelite House of David Wireless Station (Michigan)
- Japanese Sending Blank
- Makay Radio
- Marconi Wireless Telegraph Co. of America
- Massie Wireless Telegraph
- Occidental & Oriental Wireless Co.
- Pacific Wireless Telegraph Co.
- Servigo Radio Telegraphico
- Societe Anonyme Internationale De Telegraphie Sans Fil (Bruxelles)
- Stone Telephone & Telegraph Co., 1921
- Tropical Radio Telegraph Co.
- United Wireless Telegraph CO
- United Fruit Co.
- U.S. Naval Radio Service, 1915
- U.S. Signal Corps.
Series 31: TRANSMITTER CONDENSERS, 1849-1943 (Box 168-184)
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This series documents the history and manufacture of the transmitter condenser, including the extensive patent litigation which shaped its development. Included are blueprints; correspondence, 1910-1922; depositions; drawings; index of patents and publications; lists of patents and cross references to patents; outline of chronological history of transmitter condensers; patents (copies); photographs; reports; telegrams; tests; trial testimony and transcriptions. See Series L for index to photographs in Bound Volumes.
Series 32: SPARK GAPS, 1905-1913 (Box 185)
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This series contains material on various spark gaps, among which are rotary type, synchronous and non-synchronous; fixed gap, non-quenching; quenched gaps; gaskets; anchor gaps in antenna circuit; synchronous rotary spark gaps; compressed air gaps, etc. Included are diagrams; photographs; descriptions; explanatory notes; data; magazine and newspaper clippings; pamphlets; abstracts of contracts and payments; testimony; reports; correspondence; and court proceedings related to spark gaps.
Series 33: TRANSMITTER INDUCTANCES, 1907-1922 (Box 186)
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This series contains information relating to oscillation transformers; couplers; variometers; and primary and secondary coils of transmitters. Included are magazine and newspaper clippings; notes; correspondence; graphs; diagrams; drawings; illustrations; brief histories; descriptions; abstracts of testimony; and abstracts of court claims regarding transmitter inductances.
Series 34: TRANSMITTER WAVE CHANGERS, 1907-1924 (Box 187)
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This series contains information regarding wave changers in the U.S. Navy; instruction for installation and operation of Navy-type wave changer systems; notes on transmitters regarding Lodge patent; and descriptions, drawings, photographs, and diagrams regarding waves of the first submarine set for the U.S. Navy, of Priess-Bath magnetic control wave changers, and of wave changers used with 1 K.W. type "C" transmitters. Also included are testimonies, contracts, requisition, correspondence, memoranda, and abstracts of orders.
Series 37: ARC TRANSMITTERS, 1907-1940 (Boxes 188-190)
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This series contains information regarding arc transmitters, including illustrations and photographs of machines and of wireless telephone operators; brief descriptions; histories; notes; articles; diagrams; newspaper and magazine clippings; correspondence; memoranda; reports; data regarding Federal arc sales to U.S. Government, on arc contracts, etc; specifications; contracts and requisitions for arc transmitters; and resume of data on arc contracts. See Series L for index to photographs in Bound Volumes.
Series 38: VACUUM-TUBE TYPE OF RADIO TRANSMITTER, 1914-1947 (Boxes 191-192)
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This series consists of literature, data, and photos pertaining to different types and models of vacuum-tube type radio transmitters. It includes lists of vacuum-tube transmitters made by different companies; price lists; notes on the first use of tube transmitters by RCA and on arrangement of oscillation in Mercury Vapor Tubes. Instructions for the operation of various models of radio telephone sets and telephone transmitters; memoranda; correspondence; descriptive specifications; photos of machines and of people operating machines; diagrams; reports; newspaper and magazine clippings; data regarding radio transmitters; articles; drawings; general descriptions; extracts of contracts and payments for vacuum-tube transmitters; specifications; and copies of bulletins, pamphlets, and booklets. See Series L for index to photographs in Bound Volumes.
Series 39: RADIO TRANSMITTER, RADIO-FREQUENCY ALTERNATOR TYPE, 1894-1940 (Boxes 193-194)
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This series consists of advertisements; correspondence (Fessenden, l900-09; NESCO, l909-l7; Clark, l937-40); data files on Alexanderson's Alternator and Goldschmidt's relection-type radio-frequency alternator; descriptive specification for Standard Signal generator type TMVl8; schematic diagrams; and photographs. See Series L for index to photographs in Bound Volumes.
Series 41: VACUUM TUBES, TRANSMITTING TYPE, 1905-1948 (Boxes 195-196)
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This series contains advertisements; booklets; correspondence, l9l9-l940; schematic diagrams; engineer's reports and tests; grids; magazine articles; newspaper clippings; photographs; price lists; sales bulletins; sales catalogues; specification reports; technical data reports; technical information sheets; and tube test reports of transmitting type vacuum tubes. RCA and the De Forest Company are represented.
Series 43: RECEIVING SYSTEMS, 1904-1934 (Box 197)
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This series consists of advertisements; correspondence, l9l4, l9l6, and l920; charts; graphs, diagrams; news clippings; notes, handwritten and typed; periodical clippings; photographs; schematic blueprints; and schematic wiring diagrams of a complete receiving system.
Also included are materials on a transoceanic receiving system; centralized radio installation; auditorium systems; receiver with separate heterodyne driver; and hotel distribution systems. It does not include materials on static reducing systems.
Series 45: BROADCAST RECEIVERS, 1907-1948 (Boxes 197-206)
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This series includes RCA Radiola radio receivers catalogues; technical discussion booklets; technical information and service data sheets; instruction manuals; and service notes filed by model number. RCA and associated manufacturers' battery-type Radiola advertisements, booklets, catalogue material, news clippings, illustrations, photographs, and price lists. There are also replacement parts catalogues filed by name of Radiola. Other catalogues include those of General Electric, Graybar, and Westinghouse. There are also miscellaneous articles; booklets; brochures; catalogues; correspondence; installation and operating instructions booklets; newspaper and periodical clippings and articles; illustrations; instruction books; news releases; photographs; sales literature; and specifications of broadcast receivers of various companies.
Series 46: CODE RECEIVERS, 1902-1948 (Boxes 207-215)
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This series consists of material about receivers in the form of self-contained units for receiving code telegraph signals or for commercial radiotelephone reception. Descriptions of radio sets (combination syntonizers and receivers); instructions for fitting and operating different types of radio receivers; photographs; photocopies of receiver parts; data on receivers; news clippings; correspondence; reports; diagrams; notes by G. H. Clark, November, l938; articles; blue prints; receiving set licenses; descriptive specifications; and notes on various aspects of receivers. The series also consists of a number of bulletins, instruction books, handbooks, and booklets; copies of experiments and tests; copies of contracts; list of tools; extracts from U.S. Navy monthly radio reports; requisitions; and proposals. See Series L for index to photographs in Bound Volumes.
Series 47: RECEIVING INDUCTANCES, 1898-1944 (Box 216)
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This series contains articles; blueprints; bulletins; charts; correspondence; diagrams; graphs; illustrations; news clippings; periodical clippings; photographs; Radio Data Book, l907; sales literature; sketch books; and technical bulletins of low tension inductances for receivers and in test work. It includes air core inductances for receivers (standard inductances in laboratory work); air core inductances for wave meters; couplers and goniometers.
Series 48: RECEIVING CONDENSERS, 1871-1946 (Boxes 217-219)
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This series contains literature about receiving condensers, including variable and fixed types, detectors, and test appliances; standard condensers for laboratory use; protective device condensers; and key condensers. Included are mostly patents and variable patents, but also there are indexes, diagrams and drawings.
This series also consists of patents on sub-class 2 and including specification of Letter Patents on foiled paper and methods of producing same; on condensers; on electrical ignition devices; on press-plates; on press-mold; on condenser terminals and methods of framing same; on protective units, on high-frequency electrical oscillation apparatus.
In addition, there are bulletins; magazine clippings; booklets; correspondence; drawings; diagrams; graphs; reports; extracts from U.S. Navy monthly reports; pamphlets; articles; memoranda; test; and experiments.
Series 49: AUDIO SIGNAL DEVICES, 1876-1947 (Boxes 220-221)
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This series contains advertisements; articles; a bid invoice; blueprints; booklets; bulletins, specifications; correspondence, l905-l920 & l942; diagrams; instruction booklets; illustrations; news clippings; notes; patent copies; periodical clippings; photographs; service notes; a General Electric Radio Apparatus Catalog for audio-signal-indicating devices; C. Brandes, Inc. Radio advertising. Audio signal devices include: head telephones; telephone cords; telephone headband; telephone transformer; audibility meter; shunt box; group tuners where used in receiver circuit, and telephone condensers. (Box #221 is oversize).
Series 50: DETECTORS, 1878-1944 (Boxes 222-228)
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This series consists of material relating to detectors, especially where constructed as self-contained units. Included are coherers, tone wheels, tickers, magnetic detectors, vacuum tube detectors with control, complete; cat-whisker detectors; crystal detectors; electrolytic detectors; group tuners for use in the audio circuit, tone testers, detector-tester, "ticker" for testing detectors, etc. The materials contains patents, testimonies for G. W. Pickard in Pickard vs. Austin, and general data on detectors including histories; designs, specific and general; methods of manufacture, uses; tests; drawings; photographs; specifications; contracts; patents; litigation records; testimonies; inventors; names and addresses of companies manufacturing detectors; reports; articles; newspaper and magazine clippings; correspondence; notes; blueprints; charts; court proceeding; pamphlets; booklets; experiments; portions of journals; and petitions. This series does not include amplifiers, or individual vacuum tubes. See Series L for index to photographs in Bound Volumes.