The Sparks Telegraph Key Review

Spark Key Project

A Cooperative Effort to Catalog Manufacturers of Spark Keys by Collectors and Historians Worldwide

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This list will be updated as additional information becomes available. Please see AWA Review #14 2001 for much more information and for many more pictures of spark keys from the National Museum of American History of the Smithsonian Institute. Also see AWA Review #16 2003 for an indepth study of spark pack sets and the keys that went with them. Motor buzzer transmitters and the key control systems associated with these low power units are covered in AWA Review #18 2005. Emil J. Simon and his organization are documented in AWA Review #20 2007. Thomas E. Clark is covered in AWA Review #22, 2009 with pictures of his apparatus.

Although we have tried to make this summary as accurate as possible, it is difficult to differentiate between early key manufacturing companies, companies that were solely wireless operating concerns and did not manufacture keys, and companies that only distributed keys. The distinction is frequently blurred, since some companies functioned as manufacturers, operating companies and also sometimes as distributors. Many early manufacturers of complete spark outfits also made the keys that went with their systems. They probably used magnetic relay keys. The keys used by Popov were manufactured by Ducretet (per Waterbury). Similarly, no de Cervera (Spanish system) or Armstrong & Orling (a British low tension system) keys are known to exist. Please e-mail any information you have to Homebrewing of spark keys was a very common practice, and design drawings were even published in QST. Unfortunately, many commercial spark keys were not labeled by the manufacturer, and it can be hard to tell a good job on a homebrew key from a commercially made one. Hopefully this list will aid in the identification of unknown commercially made keys.

A B C D E F G H I J K L M Marconi N P R S T U V W
Company NameApprox. Years Spark Keys MadeLocationComments
ACME Wireless Construction Companyca 1909Cambridge, MARegular Morse keys fitted with a special contact to carry heavy currents. Cost $2 and up.
Adams-Morgan1911Upper Montclair, NJAMCO Junior wireless key, Simplex Wireless key, Superior and Peerless models, and "United Wireless Type" keys. Alfred Powell Morgan (1889-1972)was an author, inventor and manufacturer. Adams was a silent partner. Paul Godley of wireless distance record fame bought into the firm in 1915. Reorganized in 1926 as the Paragon Electric Corp. The company disappeared around 1928. See Douglas, vol. 1. Also made a much smaller key (the Junior wireless key?), nearly identical to the one made by Bowman.
Aktibolgat Gas
1904Stockholm, SwedenGustav Dalen consultant engineer. So far, one known standalone spark key with following information:
It was made 1917.
The base size is : L= 6,5 " x W= 3,9 ".
Lever is 7,3 " long.
Contact is 0,62 " in diameter.
One binding post has marking 33 A (maximum current ?)
There is an integral key on an airborne AGA spark transmitter from circa 1917. The label on the spark transmitter reads "GASACCUMULATOR STOCKHOLM". For later history and further information, see links and info under Ericsson listing.
Ajax Electric Co.?Cambridge, MAAlso see listing under Atlantic Radio Co. Catalog shows learners instrument as well as sending key.
Amalgamated Wireless
(Australasia) Ltd.
1913Sydney, NSW, AustraliaFormed in 1913 by a merger of the Australian interests of the Marconi's Wireless Telegraph Co. Ltd., Telefunken, and the Australian Wireless Co. Thus far two known examples 12 of a guillotine key labeled "Made in Australia" with an AWA label, otherwise an exact copy of British Marconi guillotine keys (see below.) Much more common are smaller keys labeled AWA, probably transitional keys to CW.
American DeForest1901-1914 New Jersey operating company & full line under different names. See Mayes. Business fraud while with Abraham White. Large 10 KW key reported by Moreau as made by American DeForest was probably in error and actually Marconi. Supplied the CF99 1/2 KW Motor Boat Set with gasoline engine and a "Main Hand Key." Supplied Field Set that could be motorcycle mounted, but the key appears to have been Bunnell! Succeeded by United Wireless in 1906. Mac Horton designed wireless keys for American DeForest. Originator of very popular cross-shaped spark key design that was imitated by later companies. See AWA Review #2 pg.7-20. Perhaps better known for development of the three element vacuum tube (Audion) and work in wireless telephony.
American Radio and Research Corp.
1915Boston, MA (Tufts U.) Founded by Harold J. Power at Tufts University. One of the 1st broadcast radio stations in the U.S. AMRAD also manufactured radio parts for both domestic and military use. Developed and made radio transmitters and receivers for the military in WWI and worked on a submarine detection system. Made the CA763 hand key and CA 764 relay key for the CA599 (AMRAD) 2KW quenched gap spark set. See Douglas, vol. 1 pg. 39.
American Sales Co.1925New YorkBrass wireless keys for 95 cents, 3/16" contacts. One of just a few spark keys mounted on a wooden base (they catch fire!) Possibly just distributor? Looks identical to a J-3 (trench telegraph), probably surplus being marketed as spark.
American Wireless Co.1910Boston, MA Vacuum relay key for carrying large currents, probably for the 5 & 10 KW transmitter contracts they bid on for the Navy. Also a break key for which the company applied for a patent. William Walker, President.
Annaka Electric Company1900 JapanMade a wireless transmitter as early as 1903. Made a 3 KW spark transmitter9. Established the world's first wireless phone service between Toshijima and Kamijima using the TYK wireless phone. Eventually merged with Kyoritsu Electric to become Anritsu Electric Corporation which celebrated its 100th anniversary in 1995 (Kyoritsu Electric was established by the merger of Sekisan-sha and Abe Electric Wire Co. in 1908. Sekisan-sha was founded in 1895.) A marble based spark key with the nameplate in Japanese and English is known. In response to inquiry, the company regrets that they unfortunately have no pictures of the early spark transmitters.
Atlantic Radio Co., Inc1921Mass. & Me. Ad for a key called the AJAX. None known in collections, although one of the learner's key and buzzer sets has surfaced. This company also marketed the General Radio Type 151, the Clapp Eastham Boston and Blitzen keys, Signal Electric keys, the Murdock No. 284 transmitting key and No. 285 Murdock strap key, Wireless Specialty Q-S-504 and Q-S-5004 keys, and a key called the "Straight Line Radio Key" by Bunnell: these keys all shown in an Atlantic Radio Co. catalog that does not have a date. The Boston Key was available with contact size for 10, 20, 30, and 50 amps. The GR Type 151 is advertised as handling 10 amps. Interestingly, the Ajax is NOT advertised in the catalog. It is likely that the Ajax was actually made by the Ajax Electric Co. of Cambridge, MA. Ajax Electric also made a very similar appearing practice set.
(Bing Toys)
1902GermanyEarly functional toy set with strap key, induction coil, and coherer receiver. See pg. 164 of Faszination Morsetasten.5 Continued to make toys until at least 1932.
Bowman, A.W.1911-1922+Lexington
& Cambridge MA
marked and unmarked on marble base. Supplier to Sears, Montgomery Ward. (Meteor Key, 1922). Also made a much smaller (landline?) key. Probably the same Bowman that went on to make the 1-tube Bowman Airophone, with its striking tube sticking out of the top. One of the company's last products was a 5-tube Neutrodyne, using 201-A's. Albert William Bowman started out as a die and tool maker for a piano maker (Mason & Hamlin), then started making radio components during his free time at night in a barn on the family property. At the height of production, the company employed 14 people after moving to Cambridge, MA. The company did not survive the depression. During the boom times, Sears was one of Bowman's best customers. The company also made crystal detectors after WWI. In the early 1930's, at the request of his son, William Bowman, A.W. Bowman custom produced one bug based on the Vibroplex style-- the fate of that bug is not known! A.W. Bowman died in his 70s sometime after World War II.
Brach, L.S.1920,but mfg. other items as early as 1906Newark, N.J.. The J-7 was used with Synchronous-Spark Type airplane radio transmitters. See Robison's Manual of Radio-Telegraphy and Telephony, 6th Revision, 1924, page 546. Nearly identical to International Radio Telegraph Co.'s Flame Proof Key and Winker Type C.Q. 1140 which was used in "flying boat" type aircraft with spark rigs. The J-5, J-6, and J-7 were used with the BC15 airborne spark transmitter and BC89 receiver of WWI vintage. They could also be used on the SCR-134 and SCR-135 CW/AM rigs. Not to be confused with the J-5-A and the J-7-A: the 'A' designation appears to have been appended on nearly identical keys made during the 1940's; one contract date for J-7-A is 1921. Also made retractable aeroplane antenna for World War I. Patented carborundum lightning arrester in 1911. Continued making lightning arresters and insulators, etc. until at least 1946 as L.S.Brach; in 1951 listed as Division of General Bronze Corp., and in 1968 listing in Thomas Register says 'see JFD Electronics Co.' See "Old Familiar Strains", Vol. 2 No.4/5, August 1995. Brach also made the J4, a spark practice set which looks essentially like a J6 on a board.
(Gesellschaft fuer Drahtlose Telegraphie)
1901Berlin, Germanyheavy handled keys. Complete sets to U.S. Navy. Merged in 1903 with Slaby-Arco to form Telefunken. No known examples labeled 'Braun-Siemens-Halske' or 'GFDT'.
Brown, S.G.1915London Flameproof key used in airplane, with the mica disk on top through which the spark could be viewed. Some have "S.G. Brown & Co. London W." on the front side of the key, some don't. Also made a very large 13" heavy spark key with triple detector in rotary holder. Company still exists as gyro compass manufacturing division of Vosper Thornycroft. Some keys marked "RAF" underneath. On April 1, 1918, the RAF was formed by union of the RFC (Royal Flying Corps) and the RNAS (Royal Naval Air Service). So no key marked "RAF" can have been made prior to that date.
Bunnell,J.H.1915?-1926+New Yorkat least 7 different spark key models, including a "Cootie" type key. Small brass key with cutout corners which came with frame posts in two height sizes depending on size of the contacts.Small key on composite base. Similar key, but with push posts instead of screw down posts, different size contacts, and metal strips to posts on top of key. This basic key was made by Bunnell as part of Set 2-66 well after World War 2-- set 2-66 was a landline set used on simplex circuits and consisted of 2 galvanometers, a pen register, and this key on a beautiful 2-drawer wooden cabinet. Key advertised as the "Jove Wireless Key", apparently the same as the Clapp-Eastham Blitzen Key (see Clapp-Eastham below). The Straight Line Radio Key advertised 1919. Bunnell keys were extensively modified, some by adding contacts made out of dimes-- these keys were nicknamed "dime keys." Other keys, such as this Mascot Wireless Key with its bronze lever arm and auxiliary copper strap, had larger silver contacts added to handle higher power. Heaviest of the Bunnell spark keys was on long composite base and has an auxiliary contact, perhaps for a relay or receiver. This same key was made on a shorter base without the extra shorting contacts for the receiver. Bunnell also made a Boston pattern key which sold for $7.50. "J.H. Bunnell & Co., New York, USA" is marked on the lever of the Bunnell Boston Key in the place one would expect "Clapp Eastham" to be on the more common variety of Boston Key. The Bunnell/Clapp Eastham design sharing is also evident on the Blitzen type keys, some of which are labeled with "Bunnell" on the lever arm.
Burlingame Telegraphing Typewriter Co. 1906 as the
Wireless Printing Telegraph Co.
San Francisco, CAWireless messages sent directly from typewriter keyboard equipped with Burlingame apparatus to steamships. In business until at least 1910.
Carpentier Gaiffe et Rochefort1905-1919FranceThe company changed its name to "Compagnie Generale Radio-maritime" (initials still C.G.R.) in 1910 and was eventually bought by S.F.R.-- the Societe Francaise Radio-Electrique. C.G.R. was formed to make wireless instruments under government/military contract. A very large oil break key with front and back oil cups. Picture of the original appearance of this key in 1907 military manual exists. Pictures from "Radio-électricité" Tome 1 N° 7 -December 1920" . Article titled " La marine de commerce et la télégraphie sans fil" (" the merchant navy & the wireless telegraphy ") by Lieutenant BOUILLANE: CGR 1 KW station with schematic and CGR 2.5 KW station, both with this key present. Jules Carpentier, 1851-1921, made galvanometers and Baudot telegraph instruments in 1879. When physicist Heinrich Ruhmkorff died in 1877, Carpentier purchased his Paris firm and renamed it "Ateliers Ruhmkorff-J. Carpentier, Ingenieur, Constructeur." At least one member of the Gaiffe (A. Gaiffe) family in Paris also made scientific instruments in Paris in the 1880s. Another model CGR key made for spark transmitter for boats, 1910.
Central Scientific Co.incorporated 1900Chicago. Company of same name now in Franklin Park, Illinois, selling scientific equipment for over 100 yrs."Boston" pattern wireless key shown in Hawkins Electrical Guide, USA 1917. Current capacity is given as 10-50 amps. Looks like Boston Key of Clapp-Eastham. On polished marble. See inside back cover MM47, August 1996. CENCO formed in 1900 out of Olmstad Scientific Company, which was destroyed after a fire in 1898 which killed the founder and owner, W.A. Olmstad and 10 of his staff. See link to Humboldt State University to left.
Chambers,F.B.1912-1920sPhila.,PAnickel plated brass spark key, rotary gap, loose coupler. The Chambers key was a cross-shaped key made on a marble base, and interestingly had a leaf spring and an intricate label. The Frank B. Chambers Co. was a family owned business. F.B. Chambers had been a director of the Wireless Assn. of Penn. since 1912. The company made a rotary gap in 1915, and a 32 inch loose coupler in 1917. Through the early 20s Chambers made low power tube transmitters. See AWA Review #2, pg. 121. Several pieces of Chambers gear are on display at the AWA Museum in Bloomfield, NY.
Clapp-Easthambegan making radio equipment ca 1910Cambridge MAThe Boston Key and receivers, including early 1/4 KW transmitter with beautiful wooden cabinet and external spark gap. Boston Key on marble or composite base, range of contact sizes. Also made the Boston Key JR, smaller key on composite base. Blitzen key (see Keyletter page 260), a smaller key on oval base. Repro. 1993 by Indux Corp (K. Vanslette), Ormond Beach, FL. A variation of the Boston key with the parts arranged a little differently, and another with narrow base. One known example of a diaphragm key by C-E, part of a Canadian Marconi model #1216 spark set salvaged from a submarine. A variation without the diaphragm but with the contacts on one end of the key was also made by C-E. Clapp, Eddy, and Eastham began business in 1906 making X-ray equipment. See General Radio. See Douglas, vol. 1, pg 101.
Clark Wireless Telegraph Co.1902 Detroit, MI.step lever wireless key, known only from photographs and drawings; the step lever wireless key was supplied with the sending set sent by Clark to Guantanamo in 1906. Marble base. Ad in the Western Electrician from May, 1903, clearly shows a Foote Pierson 20th Century key as part of the setup, as do company bulletins. Clark supplied MESCO triumph style keys with the Type D experimental sets. Clark made a wide range of wireless products supplied to the public as early as 1898, including transmitters, receivers and accessories. Thomas E. Clark proprietor, later in association with James Scripps of the Detroit News he was consulting engineer when broadcast began from the station that would later become WWJ. The company has diversified and still exists today as Tecla Co., Inc., however it no longer makes radio related products.
Cohen, S.
(for John Firth & Co.)
1922 or beforeNew York CityOne known model of relay key made.
P. Conalbabout 1900Milan, ItalyKey with name imprint clearly a knockoff of the famous Marconi style. Two pages from a Conalb catalog (provided by Eliseo, IK6BAK)-- apparently the company was best known for making printing supplies-- First page and Second page.
Connecticut Tel. and Elect. Co.1918CTSee info under L.S. Brach. The J-5 was made for the low power BC15 aircraft spark rig, which was made by Connecticut Tel. and Elect (see pic under Brach). Not the J-5-A made mainly in the 1940's.
"Cootie" Keyca. 1920----The Cootie key was distributed by Young & McCombs ("Radio News for January 1921") of Rock Island, IL. (incorporated 1910, sold general merchandise). But made by Bunnell, Leach, Tri-City and probably others also. Essentially a spark sideswiper. The word "cootie" was used by men of the American Expeditionary Forces in Europe in WWI. It referred to a small bothersome insect apparently similar to a flea or tick.
Cutting and Washington1916Cambridge, MA Made the CP1156 hand sending key for the CP1110 50W spark airplane transmitter. Went bankrupt by 1924. Also made receivers. Bowden Washington and Fulton Cutting proprietors. Washington studied at Columbia, and was an assistant engineer at Clapp Eastham in 1913-1914. Cutting was Harvard educated. He was born in 1886 and died in 1967 in NYC, and was a manufacturer and educator. See Douglas, vol. 1, pg. 145. Washington also made a large spark key with rear contacts to go with the 1/4 KW Panel Set3.
Doron Bros.1910-1915Hamilton,OHmarble based spark key with heavy lever. Also built tuners, crystal detectors, wireless telegraph and telephone equipment, oscillation transformers, and spark gaps. Experimented with a Poulsen type arc transmitter. Operated 8ZU 5KW spark transmitter. Made 100 wireless outfits for a large Chicago firm. Licensed in 1916 by Marconi Wireless Tel. Co. to build and sell equipment under Marconi patents.
Dubilier1912London, EnglandSmall portable wireless set with large integral key. Wooden enclosure. Entire set weighed about 17 pounds. Made a variable tone spark transmitter as pack set with key in front (see the OTB, March 1980, pg. 29). Also made electro-medical set.
Duck, Wm. 1915Toledo,OHsmall cross-shaped marble-based key. Possible ties with RECO? "Overland Key" available in 5, 10, and 20 amp models. 14 different catalogs exist from J.J. and Wm. B. Duck from 1909 to 1920. A magnetic relay key along the lines of the Gray Magnetic Relay Key, the No. A1925 Magnetic Key which sold for $5 by catalog with a shipping weight of 3 pounds.
Ducretet and Roger 1899-1919Paris,Fr.oil-break flameproof key for aircraft use and regular models. A drawing exists of the aircraft key with the spark transmitter from a WW1 (1914) French Army manual. See an excellent monograph by Neal McEwen. The very wide knob skirt reportedly contains ox blood! Also experimented with a Mercury vacuum key as did the Mass. Wireless Equipment Co. One account has it that this unusual Ducretet key was mounted mainly on vehicles and planes. One side of the base has a round shape as the key was supposedly mounted on a metal tube and fixed in place by a screw going thru the base in a hole on the side. That would have allowed the operator to put it in a vertical position after use. More likely though, the key was made to be mated with a particular transmitter and that is why the groove is there. At least two variations of this key exist, differing in the design of the lever and how it is mounted on the trunnion.
Ducretet & Roger also made an "Automatic Wireless Signaling" system, as described in "Modern Electrics." It had an interchangeable cam wheel with teeth corresponding to the Morse signals desired and was powered by a small electric motor. Its intended use was for lighthouses. The contacts were contained in the device and were of the oil-break type.
Dyna1921Paris, FranceWood based key , nearly identical to Pericaud key, for small home transmitters. Marked "Dyna" underneath. Dyna's founder A. Chabot worked for Pericaud in 1909, and apparently designed Pericaud's first crystal set. He eventually became president of Pericaud, and then went on to found his own company "A.Chabot" in 1921 with the "Dyna" trademark. The company remained in business in Paris until at least 1977. (info credit to N0UF & K5RW websites)
Eastern Precision Elec.1921New Yorkadvertised key in QST, this key has bulky parts on marble base
Economic Electric Limited1909 or earlier-about 1920?London, England 11th edition catalog contains testimonials from 1909-- no other date but probably pre-war. This catalog pictures a "powerful transmitter" and tapping key with a range of 100-150 FEET! G.P.O. Morse instruments are also pictured along with an advisory that "These Morse instruments can be used practically and successfully with our Wireless Apparatus." Also shown is a "tapping key" in the "Experimental Wireless Telegraphy" section, a strap key. A labeled key, called the 'manipulating key', pictured in different Economic catalog circa 1920 page w-3.
Edgcomb-Pyle Wireless
Manufacturing Co.
1914Pittsburgh, PAFull line of wireless equipment including a Boston Pattern key (Type CM) and smaller keys (Types AC & AD). It appears that Edgcomb-Pyle was bought out and/or moved and changed the company name. This from Alan Larsen: "In this group of items is a 1914 Edgcomp-Pyle Wireless Mfg. Co. catalog. On this catalog the Edgcomb-Pyle and Pittsburgh is crossed out and ink stamped on the cover is Pittsburgh Wireless Equipment Co. Ridgway, PA. The amazing thing is that inside the catalog is a loose addendum sheet dated January 1st, 1916 from the Pittsburgh Wireless Equipment Co. Withdrawing all of the prices inside the catalog and increasing them by 15%. Apparently the Edgcomb-Pyle company was bought out and or moved and changed their name. This would make sense as A.J. Edgcomb ended up in Los Angeles as The Wireless Shop and started advertising in QST in late 1919. As a side note I find it incredible that in 1916 Pittsburgh Wireless would still be using a 1914 Edgcomb-Pyle catalog. Granted it is a very nice 97 page catalog and the copy I just got is close to mint. It even has a little tear off slip coupon inside the front cover good for 10 cents off with your first order."
Electrical Specialty Co.1921Columbus,OH1 KW Triumph style key The station of the Electrical Specialty Company, call letters 8BYV, broadcast music, football scores, and other news at 7:30PM CST on 200 meters in Columbus as listed in Radio News March 1922 article by Armstrong Perry.
Electro Importing EICO1904-1915+New York "Electro" Wireless Key (glass base). The Electro was advertised in the catalog of 1914. The Electro was made in telegraph (No. 1117) and Wireless (No. 9212) versions. The wireless Electro was rated to 30 amperes, sported 3/8 inch solid silver contacts, had a "tongue" flatspring, & had an Opal Glass Base in white or black: cost in 1914 was $1.75. EICO strap keys were also made including the No. 1118 key supplied with the "Intercity Sending Outfit". Sold a full range of electrical products including the "Electro" Hustler Motor which cost 85 cents by catalog in 1914. Sold a practice set with the Electro "whistle" as the buzzer and the EICo strap key on a wooden board. Hugo Gernsback President.
Elektromekano?Denmark Spark or arc key with cooling flanges, similar to key thought to be made by MP Pederson. Another view of same key. Different key without cooling flanges. Original company founded by Jens Jorgensen . Later name changes to Danish Radio and Dannebrog. Made several different commercial radios around WWII. This information from Jan Skoldin.
Elliott Electric Company
(Radio Dept.)
1917Shreveport, LA from ad in QST. Bakelite and brass, $5! This company was the licensee in June, 1922 for radio station WAAG in Shreveport. None known in collections.
Electro-Set Co.1914Cleveland,OHAdvertised in the Electrical Experimenter the "Electro-Set Special Wireless Key" is similar to Duck and United Wireless but is the only marble base spark key with lantern style binding posts and cross frame. The 1916 Electro-Set catalog (B2)shows several models for sale, including the "Transo", the "Standard", and the "Leader". The "Leader" looks very similar to the "Special" that was advertised in the Electrical Experimenter. Also shown is the "No. 496 Signal Service" Key, a Boston Pattern key. There is also a strap key for sale, the F-91 "Tele-Key." Mounted on a hard rubber base, the Tele-Key was the key to be used with the 1/8" spark coil experimenters set. No.490 Amateur Key. The 1916 catalog states that the company was 2 years old at that time. The 1915 catalog No.101 shows No.409, No.491 "Mascot", and No.492 "Standard" all of which appear identical to those made by J.H. Bunnell. It also shows No.495 "Special" which was rated for up to 1KW and looks to be a company product.
Emilio Caimi?ItalyOne heavy key labeled with this name and "tasto manipolatore" currently known.
also as AGA
est. 1876Stockholm, Swedenkeys used aboard ship. Appearance similar to landline instruments made by same manufacturer, on marble base. Ericsson still exists today. From the company's website: "The company's history dates back to 1876 when the founder, Lars Magnus Ericsson, opened a repair shop for telegraph equipment. Realizing that there was a need for improvements in the telephone instruments available at that time, he started his own production."
Heavy equipment maker ASEA, gas equipment maker AGA (Aktibolgat Gas Accumulator), and LM Ericsson formed SRA Radio in 1919, The Svenska Radio Aktiebolaget. Swedish Radiola was manufactured by SRA in the 1920's. AGA produced crystal receivers in the 1920s. Gustav Dalen, a Nobel Prize (Physics, 1912) winning engineer & innovator and eventually president of the company, worked for AGA with radio early on, and experimented with transmitters and components. AGA experimented with radio between airplanes and ground stations, using copper trailing wire as the antenna. Marconi bought a minority interest in SRA at one point. The parent company AGA still exists today.
Ferdinand ErneckeCompany from 1887 or earlier, wireless advertised early as 1897Berlin, GermanyDemonstration equipment similar to Marconi.
Etheric Wireless Mfg. 1911New Yorkthe Etheric Key and strap keys. Possibly succeeded by Independent Wireless.
Federal Tel. Co.1909-1920Palo Alto,CAmostly arc sets and keys. It is common to mistake keys used with arc transmitters, and Alexanderson transmitters as spark keys, especially those marked auxilliary. Type 496, with San Francisco label. CT-1576 key w/circuit switch; Federal made a flameproof, the SE-858, similar to the Wireless Specialty Apparatus Co. Q-S-505.
French Army
(supplied by?)
?FranceFrench Army spark key with 8mm contacts.
A.W. Gamage Ltd.1913London, EnglandWireless Key Type 1914. Also a G.P.O. pattern wireless key, and a key called the "Tapping key". See Tony Smith's article in Morsum Magnificat 65, September 1999 "The Telegraphic and Wireless Products of A.W. Gamage Ltd." Gamages closed in 1972.
General Radio Co.
(Eastham after leaving C-E)
1915Cambridge MAheavy duty combination spark key and spark relay in one unit CAG 457 which was part of the CL342 (Lowenstein, 150-1000kc. 8 frequency rig used on naval vessels) 2 KW set and CL344 2 KW Quenched gap set (1918). Type No. 151 flame proof aircraft key (10 amp). Looks like (but isn't) J-5, which was made by General Radio, Brach, and Conn. Tel and Elect. Also model with cooling fins on both upper and lower contacts. CAG 468 combined hand and relay key which along with CL462 was part of CL345 (1917). Unusual asymmetric design, marketed by MESCO in 1916 but probably made by GR. CAG-1169 was a flameproof key with a 2 inch chamber with 1/4 inch contacts within, and the SE 1140 was the CAG-1169 with a transformer 110 to 6V with 6-volt blinker lamp. General Radio was still doing business in 1975 when it changed its name to GenRad. In October of 2001, GenRad was acquired by Teradyne, Inc. For a 129 page .pdf download called "The History of the General Radio Company 1915-1965" by Thiessen, go to this site.
Gilbert, 1917New Haven, CTGilbert Wireless Telegraph Outfit, a youngsters teaching outfit that probably had a range of no more than a hundred feet or so. Integral strap key.
Gray111910EnglandGray Magnetic Relay Key. Part of typical Marconi marine setup circa 1910. See W.W. Bradfield. Not actually made by Gray-- made by British Marconi. Made in single and double magnetic relay versions. Used in conjunction with spark key such as guillotine key made by British Marconi. The Gray magnetic relay key was intended to preserve the contacts on the spark key by delaying the break of the contact until a zero current point. Also a good discussion in Hawkhead and Dowsett.
Halcun Radio Co., Inc.
(Haller-Cunningham Electric Co.)
1919San Francisco, CA Halcun Commercial Type Transmitting Key, rated at 50 amperes. Cross-shaped leg key. Standard finish, polished copper. Also available on marble base. Also marketed a 1/4 KW rotary gap transmitter and a loose coupler.
Wilhelm Hess
Optische Anstalt
1910Kassel, GermanySold teaching equipment including nr. 4428, a 10 cm long key on its own base. Also sold a coherer, simple gap, and other pieces for wireless telegraphy. See Faszination Morsetasten, pg. 165. Company is still in business.
Independent Wireless Telegraph Co. Inc.191967 Wall Street, NYType K-1 2KW Hand Key, 120V, 10A, 500 cycles. Labeled keys on slate base with heavy contacts and parts. Another model pictured in Antique Radio Classified Oct. 1988-- lever angles steeply toward knob, cooling fins. Also made Panel Radio Transmitter type B-1 (300-600 meters). Logbook "Instructions to Operators" by IW. Also was an operating company. An Independent Wireless lawsuit against RCA is still cited as a precedent in patent law cases-- Independent Wireless Telegraph Co. v. RCA, 269 U.S. 459, 466-67 (1926). Possibly succeeded Etheric.
International Radio Telegraph Co.
(succeeded NESCO, see below, and eventually bought by Westinghouse)
ca. 1920Pittsburgh, PAFlame Proof Key and Winker Type C.Q.1140 probably made for use with the CQ 1115 200 watt and the CQ 1111 500 watt transmitters (also known as SE-1300 and SE-1310 when assembled as complete outfits) which were used in flying boats-- Naval Aircraft. Keyed synchronous-spark type equipment powered by a wind-driven generator (CQ1265) mounted on the wing of a plane. C.Q. 1115 also supplied to the Army Signal Corps. A picture and diagram exist of this arrangment using this key. Two keys were used, with the second key referred to as the "observer's key", presumably mounted in front of the observer seated behind the pilot. It is likely that the winker bulb was provided so that the observer could see what was being transmitted on the pilot's key. See Robison's Manual of Radio-Telegraphy and Telephony, 6th Revision, 1924, page 546. Navy CQ-1213 (another key similar to Signal Corps J-7), consisting of General Radio type CAG 1069 and signal lamp on bakelite base, transformer included.6 It is likely that this company also supplied the SE 1443, SE 1443A, SE 1443B, SE 1443C and SE 4015 key and winker. These keys were transitional keys used both with CW and spark rigs. This company manufactured the SE-1300 and SE-1310 outfits mentioned above, and the SE 4015 is noted to be part of the SE-1310.
International Wireless
Signal Co.
1912NJThe 'Inwesco Universal Sending Key'. On a marble base and has a 7 inch lever. Sold originally for $6.50.
Jardillier, 1913Paris, FranceOne of several companies that made wireless keys similar to the one shown under "Dyna." Jardillier is better known for its many models of landline keys. Jardillier was still producing keys into the mid 1950's and perhaps later.
Kapsch & Sonsfounded 1892Vienna, AustriaNr. 15321 in catalog available as special order and described as "Braun'sche Taste", in other words a Braun-style key. Picture in catalog is identical to Braun style keys. See "Faszination Morsetasten" by Gregor Ulsamer, pg. 63 (German text).
Kilbourne and Clark1901-1920+Seattle, WASE-68, SE-1865 which was a 1/2 KW key with an auxiliary contact for use with a TM set 4. Edward Corliss Kilbourne was a Seattle dentist and lived to be over 100 years old (1856-1958). After Seattle's great fire of 1889, Kilbourne received the city's franchise to restore electric power and in 1892 he became majority owner of the future Union Electric Co. Kilbourne himself retired from active business in 1910. Walter G. Clark was Vice President and Manager and was an electrical engineer. Clark interestingly made the first ascent of Mt. Olympus, WA, in 1906. Frederick G. Simpson was Chief Engineer. This Kilbourne & Clark key was used by Radio Operator Carl Peterson to send the radio message from radio WFA to the New York Times announcing that Commander Byrd had crossed the North Pole by air. WFA was the call sign used by the Little America expedition. Blueprints exist for the following Kilbourne & Clark spark key models:

SE-68, (KS-926), 1 & 2 KW Auxiliary Hand Key, dated 12-27-17.

Type A Relay Key, 1916 (Form 4). Three variations of this basic relay key were made. A "front connected" version (KN-316 & KN-386) was made in 1913, as was a "back connected" (KN-317, a leg key) version. These two versions appear to have had a "make & break" attachment on the end of the armature lever. The 1916 front connected version (KN-698) did not have a make & break attachment.

Type A Key 1-5 KW 1911. Drawing dated 12-29-11, (JN204) Black fiber base, 3.5" x 6 5/8". "Signal Corps U.S. Army" initially intended to be stamped in fiber near knob disc under contact button. Parts nickeled brass.

Type B 5 KW key 1914 (Form 2). KN390. Drawing dated 1/5/1914. "XX Dilecto" base. Base 3.5" x 6 5/8".

Type C (with long key lever) 1914 (Form 1) Drawing dated 12-12-1914 (KN563). Key was made with cutout for front right side of receiver. Base 6" x 2 9/16". Lever probably began 7 5/16" and was later shortened to 5 9/16".

Type C Form 1 Hand Key (KN802). Drawing dated 1-26-17. "Micarta" base, 5.5" x 2.5". Brass frame and lever.

Type C Made for 1,2 & 5 KW Navy radiotelegraph transmitters. (cross-shaped) key 1917 (Form 4). KM903. Drawing dated 8-17-17. Base 5" x 2.5", brass hardware. Made for BuSE. Initially intended to have a standard BuSE nameplate on side of base, but decision apparently made to leave it off at some point.

Type C Form 3, 5 KW Hand Key HS 825 January, 1917. Base 7.5"x 3.5".

Type D 2 KW hand key 1918 (Form 1) Drawing dated 6-25-18. (KN1055) Base 4.75" x 2.5". Brass hardware. Lever with "wings" coming down to lever support.

Type E 1/2 KW diaphragm key, flameproof, Simon design (binding posts in a different place), 1918 (Form 1)(KR-1069). Drawing for diaphragm key exists. This key was originally designed for use on a combined base with an antenna switch.

Balanced Hand Key (Commercial version) was a post World War I (1920) spark key made by K&C. It was made in both the commercial 1/2 KW version and ham radio version, with the commercial version a bit larger. Both have a "polished dilecto base." Stamped and bent topside steel parts. Advertisement shows the ham radio version, with cost of $4.50.

KM 800 Hand Key for use with 20 KW Simpson Quenched Gap transmitter. Drawing dated 1916. Base was 7-3/8" x 3".

The first 20 or 30 KM 903s were made on surplus bases from WSA Co. detectors that were cut down to size. This can be seen from the underside-- there is an extra hole that is not used hidden on top.

Type B Form 1 Relay Key, KR-965, 12-4-1917, like the Leach Relay Key

Personal recollections of a K&C employee regarding the company's history exist in letter form:
Page 1
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Page 5
Max Kohl A.G.(founded 1876)
Chemnitz, GermanyKey shown as number 63,334 in 1909 catalog. For heavy currents, replaceable carbon rod contact point which is held in clamp and advanced as needed. A large key with the contacts above the main parts. Max Kohl also made a more standard Slaby-Arco style key, as well as spark coils, Leyden jars, galvanoscopes, inductive repulsion apparatus, condensers, and other related wireless and scientific gear.
Oil Break Key with "Lagier" logo on front; almost identical to the SFR Type MP except that it has large load compensating contacts on the front (load compensating contacts are not oil break.) Lagier was a small factory in Marseille ,third largest city in France located in the south. Lagier made some sets for the French army during WWI but probably not before the end of 1917. They also made civil 4-tube radio sets. We do not know more about the trade mark and the factory, destroyed about 1988, and do not have any documents or advertising about it. There are some rare spy sets probably dated around 1955 and they always worked with the ministry of Defense. The company itself probably disappeared around 1960.
Leach Relay Co.1919-(present)San Francisco, CAMade a "Cootie" key (see 'The Radio Trade Directory, May 1925') as well as spark relays. Later, made the Speedoplex bugs in the 1920s and 1930s. The Cootie keys may have been transitional between spark and CW. Company still exists as Leach International and makes a full line of relays and switching products. Val Leach who was a radio op in WWI and founded the company died in 1941. The company moved to Los Angeles in 1929.
Lehmkuhl 1926Oslo, NorwayLarge key labeled with "LEHMKUHL" and a logo "L". Finned contacts. One has nameplate reading:
"ingenior j. lehmkuhl
nr 962 oslo".
According to Norwegian reference books, the engineer Joakim Lehmkuhl (born September 22, 1895) founded his own engineering company Lehmkuhl Verksteder in 1926 at the address Nedre Vold gate 1, Oslo. This company merged into the jointstock company Lehmkuhl in 1976 and in 1979 the Lehmkuhl Radio Systemer was established at Nesbru outside Oslo. Administrating director in 1986 was Ole Kristian Ree. Their sales in 1986 was 186 million Norwegian Kroner and the company had 100 employees at that time. Also made a key identical to the one without the nameplate, but completely without identifying markings. At least 2 different models known. Lehmkuhl was also making radio receivers in 1926.
Liberty Electric1916-1919Port Chester NY SE-68A SE-923. The Liberty Electric SE-923 is identical in design to the Boston Navy Yard SE-923, but both are slightly differently shaped than the SE-923 made by Lowenstein Radio. Liberty also made triumph style straight keys, and sounders. Formed by Mr. P.R. Mallory to supply equipment for the war effort, Harry Shoemaker was Chief Engineer. After Liberty Electric closed down in 1919, Mallory formed the Independent Wireless Tel. Co. See pg. 214 'Wireless Communication in the United States' by Thorn Mayes.
Oliver Lodge/Lodge-Muirhead1897Liverpool, England Complete specifications from December 8, 1897, including drawing of key used.
Lowenstein Radio Co.191810, but drawings of Lowenstein keys as early as 1916 existBrooklyn NY SE-923. also SE-68. Fritz Lowenstein, an Austrian immigrant, is credited with the "wave changer", a tubular quenched gap, and the 'C' battery. Assistant to Tesla. Hand Key CL462 (same as the Type A key but with a 1918 Navy label) was part of the CL342 2 KW set (along with CAG 457). 10 KW Hand Key CL830 along with Relay Key CL419 was part of CL343 10 KW Quenched gap set (1917) and CL344 2 KW Quenched gap set. Lowenstein Type A key, with rear pivot for use with 2 & 5 KW radio sets as was the Type "B" relay sending key, see "CQ", Mar. '99, page 43. Type AH key, 235 volts at 45 amps. Like the Type A key, but different spring retainer assembly. Drawings for Type A. Drawing for SE-923, which was part of the Lowenstein Model "V" 1/2 KW Radio Transmitter designed in 1919. For discussion of Lowenstein, see "The AWA Review", Volume 9, 1995, page 205. CL484, CL485, CL486 5KW combined hand and relay keys, picture of station with Lowenstein hand and relay key in position in front of Marconi antenna switch. CL487 5 & 10KW relay key. CL830 hand key. CL420 10KW hand key hammer break for spark. Also made the SE1579 Buzzer set which had a MESCO CAM-1609 key. See MESCO below. Made the Lowenstein Type C.B. 10 KW radio sending key under U.S. Army Signal Corps order 6278.
M.A.E.S.1915?Trevoux, FranceEbonite base, heavy levered key with large contacts. This key was used on the E-3 transmitter of 1917 and on the third version of the PP4 (PP4 ter), a straight gap transmitter. See MM56 February 1998 pg. 32. M.A.E.S. stands for "Manufacture d'Appareillage Electrique Special" (Manufacture of Special Electrical Equipment), as noted on the cover of a catalog from 1920. This company was a small parts and hardware manufacturer before the war and was pressed into service making radio parts during the war. M.A.E.S. are the letters on the trademark logo of the "Societe Anonyme des Condensateurs de Trevoux", the "Condenser Company of Trevoux, Limited" in translation. Trevoux is a city in Ain in France where the factory was located. The company logo with the letters "M.A.E.S." and a condenser and two rheostats is present on the very interesting cover of a catalog from 1928 of the Societe Anonyme des Condensateurs de Trevoux.
MP-Pedersen1910DenmarkUnmarked key with cooling flanges-- could have been for ARC!. Another key without cooling flanges. Started out as Skovmand & Petersen about 1914, later called MP-Pedersen. Info from Thomas Scherrer OZ2CPU:
MP Pedersen made morse transmitters and keys from 1910 to 1940. Many different types exist, he only made Straight keys. Most of the original types are from 1920-30, but they were copied by 2-3 different Danish companies and continued after MP Pedersen did not make more. They made 3 types I think up to about 1950-60.
MP Pedersen was an active radio amateur, he made many homebrew projects in the early days, those receivers and transmitters were copied in great numbers by other radio amateurs. The first was made with Valdemar [Poulsen? --ed.]-- they are known as spark [arc?-- ed.]transmitters, and they were made before the radio tube was invented. MP Pedersen later started a company that constructed radio tubes and repaired and developed radio gear. To hide his activities from the state he called the company a cigarette company, since the state had a monopoly over all transmitters and receivers, and it was illegal to make and sell radio equipment.
And this from Hans Buhl, curator of the Danish Steno Museum:
Martin Peter Pedersen (1887-1979) got a position in Poulsen's Danish company, Det kontinentale Syndikat, just after he had graduated as an electrical engineer in 1912. Soon he changed to the English arc company the Universal Radio Syndicate where he worked together with another Danish electrical engineer, Otto Skovmand. In 1914 they formed their own Danish company with the name "Skovmand & Pedersen". They produced various kinds of radio equipment. Much of this was based on CW and de Forests Audion, which they introduced to Denmark. This fact makes it rather doubtful, that they also should deal with telegraph keys for spark transmitters. Anyway I've have never seen anything about that. But I haven't looked for it either. Skovmand died premature in 1919 after which Pedersen changed the name of the company to M.P. Pedersen.
Mach. Div. Boston Navy Yard ca. 1915Boston, MA SE-68 and SE-68A (redesigned lever) which is one of the most common of the larger spark keys found, SE-144 Flameproof Hand Key for 1, 2, and 5KW submarine radio transmitters. SE-86 (superseded by the SE-653) 1/2 KW Flameproof Hand Key made for submarine transmitters. SE-137 2 and 5KW Relay Keys. Early relay key of this same type only labeled "relay key." SE-923. Walter Chadbourne specialized in keys at Boston Navy Yard. Originally known as Charlestown Navy Yard, it is one of the oldest shipbuilding facilities of the US Navy. Began building ships during the Revolutionary War. The land was purchased in 1801 and the Yard established.
Marconi (American-- Marconi's Wireless Telegraph Co.)1899-1919
(Aldene, NJ plant mfg starts 1912)
New York and New JerseyBlueprint for the CM425, which was produced with the lever either sharply angled or gently curving down toward the knob. It appears that the earlier serial numbered ones have the gentle curve. CM425 along with the CM408 (CM 408 drawing & standard instruction sheet) and CM428 relay keys was part of a 2 KW Quenched gap set (CM306-used in air stations, CM307-used in battleships, destroyers, tenders and auxiliaries, CM309); 5KW Signal Corps 1917; This same 5KW key design was made for the Navy as the CM410, and was the main hand-sending key for use with the 5KW sets CM297, CM299, CM300, CM301, CM302 & CM303. 5KW Navy Dept. SE-179 1917; SE-482; Roadmap. The Roadmap key was probably made at the Aldene, NJ plant and is shown in a 1912 catalog. It was designed as an inexpensive key for the experimenter, in 15 amp and 30 amp ratings. There are at least 2 different variations on the Roadmap. This variation was the type C key supplied with the Type P-4 2 KW Panel set, the P-5 1/2 KW set, and the P-9 1/4 KW set. Type C key in Marconi pack set. Other hybrid versions exist. SE-68. Type A No. 217 ad (like United Wireless, 4KW)and key (and Navy drawing); No. 205 2KW key (cost $2.00 in catalog, available in black or speckled composite base).Other models without ID exist; At least 2 Weingarten repros13. The real Marconi and the Weingarten repros can be told apart by the labels (268K file) (same holds true with the Massie/Weingarten repro labels.) Succeeded by RCA. SE-86 which was part of the CM98 1/2 KW Motor Boat Set with gasoline engine drive, and part of CM296A 1/2 KW Quenched Gap Panel Set. The SE86 was sealed to the base in order to make it a flameproof 1/2 KW hand key. The CM86 key was used in the CM296 1/2 KW Quenched Gap Panel Set. "Aeroplane" set knee type hand key CM394 to go in CM295. Relay Key CM409 and hand key CM410 (drawing of CM410 and standard instuction sheet) to go in 5KW set CM297, CM298, CM299 and CM301. Hand key CM420 which was part of 10KW set CM304 (95-400 kc rig on 8 frequencies for use in battleships). Marconi Service News booklet, 1919. Marconigram. See "The AWA Review", Volume 9, 1995, page 7. Marconi catalog. Preston-Lamson Terry Key, 1910. CM437 hand key for 1/2KW commercial type set CM433. High tension relay sending key with blower about 1915, and image of several of these keys in use at Marconi wireless plant, Kahuku, Hawaii-- note flame on contact being made. Another MWTCo of America relay sending key about 1915. Solenoid key for 25KW 500 cycle XMTR built for United Fruit Co. by MWTCo of America 1913, note the two blowers for blowing out the spark on break. Covered Marconi key as supplied with airplane transmitter and aerogenerator for U.S. Navy in 1917. Sarnoff's key while at Marconi. CM858 Relay keys and transfer switch (and drawing for the CM858). Remnants of the massive Marconi/RCA transmitting station KPH can still be seen at Bolinas, CA by visiting the Point Reyes National Seashore. The big antennas and the big compressed air cooled disc type spark discharger are gone and all that can be seen are the buildings and some of the poles that probably supported the transmission lines. The main building at Bolinas is now occupied by Commonweal, a hospice like group that cares for the ill. There is an aerial view of the site inside the building. The huge receiving station at Marshall, about 20 miles north up the coast from Bolinas, is now a Conference Center. Some of the history is still being preserved, including the original residence building there.
The Type No. book for 1921 lists (some Marconi) keys with "UQ" prefixes. It seems likely that these keys were also intended for CW sets, and the "U" stands for "Undamped" with the "Q" referring to keys. Compare to the tubes used in radios such as the UV 200, UV 201, etc where the "U" again stands for "Undamped" and the "V" would referred to the tube:
UQ 621 -- for use with 2 KW spark sets. A "type C modified" design by Marconi to take a different set of contacts. Used on Marconi P-8.
UQ 809 -- hand sending key for use with 1/2 KW set US 612, and for use with 1/2 KW Marconi mule pack set
UQ 669 -- for 10 KW spark set (similar to CL419)
UQ 833 -- (same as CAM 833 by MESCO) Hand sending key for 1/4 & 1/2 KW spark sets
UQ 394 -- part of ES 3501 1 KW spark set
UQ 437 -- part of Marconi P-5 spark set

Marconi of America also made a small wooden box containing a folded paper and foil condenser and with their label with a serial number on the front. The box was intended to be connected across the contacts of a spark key to reduce sparking at the contacts. Many of these boxes are missing the labels, which were taken off to be placed on other Marconi products deemed more collectible!
Marconi (British)
(Marconi's Wireless Telegraph Co., Limited, London)
1897-1920sChelmsford, England many models, no ID. Grasshopper key, which is U.S. Patent No. 650,109 filed Oct. 12, 1899. Early model with tall handle. Guillotine key, supplied with the 1/2 KW Marconi set in 1914 & the 5 KW battleship set in 1915 among others. Guillotine key was supplied to Atlantic ocean liners in 1912 and probably before. A detailed discussion of the guillotine key is on pages 145-147 of Hawkhead and Dowsett, Handbook of Technical Instruction for Wireless Telegraphists, Wireless Press Limited (Marconi House, Strand, W.C.), London, 19158. Another British version with no Model No. The Type 365A key was probably made after the spark era, and was likely intended for use on CW. However, it is commonly seen in vintage photographs in the operating position in front of quenched gap transmitters and was probably used to key auxiliary spark rigs aboard ship in the 1930's. The covers of these keys were often used by the ops as ashtrays! The Type 100 key is labeled "Marconi Wireless Telegraph Co. London." A rear pivot key was also made with provisions for normally open or closed contacts. Another British Marconi with no model no. and recessed upper surface typical of many later models, used on 1.5 KW Marconi sets. An old stock list or catalog lists Marconi type 111A key as a "Key, Transmitting with back contacts for operation of a 1/4 KW set from ships mains." See MM75 pp. 45-6. Marconi also made a (M-1, etc.) pack set for mobile operation before and during WWI; also the Type K Knapsack set in 1913. Marconi key encased in brass used by British Navy in 1917, casing prevented key sparking from affecting simultaneous operation of receivers on the vessel (per G.H. Clark). High tension signalling keys sparking when in use, Clifden. Model with flat spring on slate & wooden base. Oil break on typical Marconi wooden base. Many repros on the market, including some beautifully made by Phil Boyle.
See also the Gray Magnetic Relay under "Gray".
One key labeled "Officine Marconi Genova" with a serial number over 15,000-- it is not clear at this point whether the key was actually made in or for the Genova, Italy office. As in the case of the Conalb key, this key is a direct British Marconi knockoff.
The Marconi Wireless Telegraph Co. of Canada, Limited1902-1920Montreal,Quebec Operating company only til 1912. Type 705 key. Type 702 key (with fancy label), Type 701 and probably others. Transmitting relays at Glace Bay (1912) with flame shooting out the top! See the "AWA Review" Volume 14, 2001, page 92 by Roger Hart & Robert Murray. Also a key, probably by Canadian Marconi, with same hardware as the wooden base keys, but much less glamourous in appearance and no label on a marble base.
Massachusetts Wireless
Equipment Company
(George W. Pierce)
1908MAOdd looking mercury vacuum key , a relay key with the contacts in glass container; also the 'back stroke' key that looks like about 1/2 of a landline key.
Massie1905-1909R.I. Operating Company and large handled key that was supposed to be operated from the standing position (four original Massie pump handle keys are known to currently exist)-- more repros by Phil Weingarten exist than originals probably. The large pump handled key was used in Rhode Island and Alaska. Drawing for large handled key. One Massie oil break known to exist, consisting of an Electrical Construction Company step key (San Francisco, 1870s) and an oil reservoir where the action takes place. One or two other Massie keys reported to exist. Authentic Massie key with slender lever mounted on slate. This slender levered Massie key was also produced as a leg key, as shown in this bottom side view of such a key that has had the legs cut off for display.

On pages 23 and 24 of the AWA Review of 2001, I discussed the slender Massie slate based key, shown in the article in Figure 33. I ended that discussion by stating that the key was a bit of an enigma, as it showed up in 1916 in the Sears Catalog as the "Commercial Wireless Key." Until now, the Massie Key and the Sears Commercial Wireless Key, made after Massie was absorbed by Marconi, were assumed to be identical-- but it isn't so! It appears that the original Massie version can be distinguished from the version sold later by Sears. The knurling on the hardware is more plain and looks cheaper on the Sears model, which also lacks the base plates protecting the slate underneath the lever travel adjustment screw and the spring. The original spring on the Massie was conical; it was the same diameter up and down the spring on the Sears model. These differences can be made out (with difficulty) when comparing the Sears catalog with the picture on page 35 of Massie and Underhill's "Wireless Telegraphy and Telephony", published in 1908. The differences are much more apparent with the two models in front of you, and they match the differences seen between the catalog and the book. It is still unclear whether the Sears version was made by Massie or not, whether the design was bought by Sears and made by another contractor, or whether another manufacturer simply started making a copy of the key after the original company was no longer around to care.
Authentic Massie key on wooden base, along with a diagram for it and the oil break Massie key. Nice picture of three Massie keys in Wireless Telegraphy and Telephony by Massie and Underhill, 1908. Beautiful cover to company literature. Massie was eventually absorbed by Marconi. The original Massie station at Point Judith "PJ" was moved to East Greenwich, RI where it can be visited as one of the main attractions of the New England Wireless and Steam Museum. Walter Wentworth Massie (1874-1941) was a pioneer in the field of wireless technology and communications. "Son of a Providence banker, Massie trained as an engineer at Brown University and Tufts University, and entered the Providence City Engineer Office in 1896. He began experimenting with wireless technology in 1895. In 1903 he resigned his city job and started the Massie Wireless Company. Initially operations focused on ship-to- shore communication, but Massie Wireless also built radio equipment and outfitted entire stations for contract clients, including the military. A significant innovator, Massie received twenty patents between 1904 and 1909, and was a key figure in the development of many industry standards." (quote from Nat'l Park Service webpage).
McIntosh Electrical Corporation1922Chicago, ILBent trunnion on a brown marble base with label. Others, made by McIntosh but possibly much later (even WW2?), with similar construction on an ugly composite base but look like they have mounting screws and belong to a larger piece of equipment and have no label. Also made medical nerve/muscle testing equipment such as an electrical belt, and the "Sinustat", a quack medical device designed to treat sinus problems with small electric jolts! This company first shows up in the Illinois Secretary of State List of Domestic and Foreign Corporations in 1922 and is no longer listed by 1946. It is listed as a "foreign" business, meaning incorporated out of state, with Geo. R. Hogan as the agent and the corporate address 223-233 N. California Ave, Chicago. At the same address and with Geo. R. Hogan as its agent also is the McIntosh Battery and Optical Corporation listed as a domestic company with $40,000 authorized capital stock. The McIntosh Battery and Optical Corp. can be traced at least as far back as 1907 in the List, though in that year C.Alfred Smith was the agent and the address was on W. Randolph Street in Chicago. It would thus appear that the McIntosh Battery and Optical Corporation, which made and sold medical equipment to physicians, split off the McIntosh Electrical Corporation in 1922 which then outlasted the parent company. The McIntosh Electrical Belt was advertised for $10 in 1890 by its designer Dr. L.D. McIntosh.
Manhattan Electric Supply Co. (MESCO)ca. 1910
for spark keys
New YorkMesco Hand Radio Key with replaceable contacts, rated at 1/2 KW (a fancy triumph key look alike). Also the Mesco Jr. Wireless Key and the #51 key, all small keys. The "Heavy Wireless Key" List No. 442, 1KW to 3KW capacity listed in the 1912 MESCO catalog. CAM-805 and CAM-1189 which were part of the SE-1075 1 KW 500 cycle transmitter (315-1000 kc 6 frequency rig for use in submarine chasers) made by International Radio Tel. Co. CAM833 (MESCO No.80) hand key 1/4 and 1/2 KW, used with CAG457 among others. CAM809 (1/8" contacts, used in connection with relay keys, MESCO No.81); CAM1609, as seen here as part of SE1579 Buzzer set by Lowenstein Radio Co. MESCO keying relay with 5/8" contacts made on bakelite base. L.G. Pacent apparently proprietor of MESCO. The company was founded in about 1880 and the last known ad is 1931.
Murdock, Wm.J.founded 1896Chelsea, MAmarble base, 1/4" contacts, larger key. This company also produced headphones etc into the '20s & radio receivers to about 1985! One strap key, the No. 285, has a simple lever. Another strap key, the No. 286, has a more complicated lever and was supposed to handle up to 15 amps and was on a marble base. Early Murdock catalog (ca 1909) shows that some of the low power spark transmitters sold by the company (e.g., the 3-5, & 6-10 sparks sets) were supplied with regular landline keys with circuit closers. Beautiful oscillation transformer on wooden base. See Douglas, vol. 2, pg. 191.
Nanao Musen Denki?Japanprobably others from Japan also. Nanao is a glass base key with heavy British style influence but made in Japan.
National Electric Signaling Co.
1902PhiladelphiaOne example of a larger key known to exist at AWA Museum marked with this name. Also made the "Fessenden Sending Key" available in 2 KW and 5 KW models. This was a Fessenden company. A drawing exists of a Fessenden oil break set. Founded in 1902 by two Pittsburgh millionaires in order to promote Fessenden's efforts. Fessenden relay keys from 1905 and 1908 .
National Electric Supply Co.
1899Washington, D.C.supplied keys to signal corps, mainly as part of airplane and field sets. See AWA Review No. 8, pg. 117 for complete history. CN581 hand key for 1/4 KW set with break attachment and detector protection, detector crystal carried on the lever (used with CN 241, CN 251, CN 252, CN 253, and CN 254 pack sets.) CN582 key with detector crystal carried on key lever for use with 1/2KW motor boat set CN100, ca. 1917. Also supplied a hand key with the CQ154 (Int'l Radio Tel. Co.) 1/2 KW Motor Boat Set requisitioned 1918. The company reorganized into International Radio Telegraph Co. Unfortunately, both this company and the National Electric Signalling Co. were known as NESCO. Early field sets by NESCO included sets in 1908-1917 for the Signal Corps, & the Navy "Sweet" and Fleet sets, "Battleship" sets, and the Type A, B, C, D, and E pack sets. These all used simple keys and mainly quenched gaps. NESCO made the SCR-49 pack set in 1917, for which the J-2 was the standard key (presumably made by NESCO?)
Navy Yard, Portsmouth, NH1921Portsmouth, New Hampshire Made the SE3546A Morse key for the Motor Buzzer Sets of the U.S. Navy. These were low power transmitters for intrafleet communications. The SE3546A had front contacts for the keying through the relay key of the main transmitter, and back contacts for the receiver protection system.
Nichols Electric Co.1914New Yorkthe "Nichols Low Price Wireless Key". Sold for 70 cents by catalog. Looks like a Beeko key on a base. Key just above it in catalog is clearly a Bunnell. The "Nichols Low Price Wireless Key" may have been made by Bunnell and marketed by Nichols under its own name.
Pericaudca 1909-1920+Paris, FranceOne known model of brass spark key on wood base. Intended to key low power transmitters. G. Pericaud also made detectors and later vacuum tube receivers. See info on Dyna for similar model and more background on Pericaud.
Frank B. Perry
& Sons
1917Newton Center,
The CAP67, a Radio Buzzer-Blinker Signal Set, a wireless training key. Also made in a commercial model in 1917.
Pittsburgh Wireless
Equipment Co.
1916Pittsburgh PASee listing under Edgcomb-Pyle.
Radiguet and Massiot1918 (1880-1940)Paris, FranceType 4A, the key from the French portable set Model RM 1918. Like U.S. Signal Corps J-3, the knob portion of the key is hinged and can be turned around at right angles so as to be out of the way when the cover of the box is closed.
Radio Engineering Co.1920Baltimore,MDRECO. Boston pattern key. See ad June 1920 QST. Also see detailed history of RECO in John Dilks's article in April 2006 QST article on page 91. Company was effort of Charlie King, Ted Duvall, and Frank Laurent with Laurent being the machinist. The RECO key was a copy of the Clapp-Eastham Boston key.
Robertson Clock and Instrument Companyca. 1921Detroit, MI oil break key. John H. Robertson manufactured "special radio apparatus" and died October 15, 1946 at age 46. The oil break key was made on white or gray marble.
Rouzet1912France key used in airplanes with spark transmitter system "Rouzet" (rotary spark gear). In 1912, Lucien Rouzet produced a lightweight transmitter which were purchased by Naval and Military services. See MM28, June 1993. A picture shows the alternator for the Rouzet MS50 which mounted under the wing of the airplane, and the key and spark box. The key looks like a STM and it is possible this is an STM key made for Rouzet apparatus. The MS50 Model spark transmitter for aircraft was a rotary gap model. Rouzet also made the AR13 spark transmitter for aircraft.
Lucien Rouzet was born in 1886 in Dieuze. He operated telegraph during his military service, and then advanced wireless aeronautical communications by developing very efficient lighter transmitters. Rouzet conducted tests of aircraft wireless as early as 1912. Rouzet died in 1948. Rouzet's son wrote the Wikipedia article about his father, according to Rouzet's grandson Marc.
Russell and Stollprob 1920sNew Yorkone model, brass parts on heavy black base, brass parts similar to smaller Bunnell. Russell & Stoll was a manufacturer of electrical products. Similar to an early Marconi design, the Russell & Stoll base contains a large condenser (Stromberg Carlson) and mica insulation (similar in that regard to Signal Electric) to prevent sparking at the contacts. Acquired by Midland Ross. Robert Aime Rostan design engineer for Russell & Stoll.
Shoemaker, Harry1901while working at DeForest,
Consolidated Wireless Co.
and others
relay keys with solenoids on the bottom, or on top and bottom; also a Greeley Victor key modified for wireless work. Designed a radio controlled torpedo also. Harry Shoemaker filed forty patents between 1901 and 1905.
Signal Electric Mfg Co1916-1928+Menominee, MIcommon small brass keys with mica (Isinglass) underneath. Distributed by Radio Specialty Co. and undoubtedly others. An ad (213K file) exists which also seems to show a Signal Electric cross-shaped key on what appears to be a marble base with three different contact sizes-- 1/8, 1/4, 3/8". They are called the R-65, 66, and 67. Company was originally founded in 1892 as Menominee Electric and Mechanical Co. Plant burned in 1904, rebuilt. Reorganized in 1919 as Signal Electric Mfg. Co. Purchased in 1952 by King-Seeley Thermos Co. Vernco Corp. of Tennessee buys the division from King-Seeley in 1964. Earliest spark key ad ca. 1916.
Simon, Emil J. 1915New Yorkpack set and collapsible key. Could have been CW but more likely spark. Simon subcontracted all production and assembly, having no factory of his own (per Alan Douglas, Radio Manufacturers of the 1920s). CE867 flameproof key supplied with CE861 1KW set. CE611 hand key 1/2KW for use with panel type set SE606,SE606A, and CE 827. CE693 hand key for 1/2KW aircraft spark set CE615 and CE700. The CE693 is a diaphragm type key2. The contacts are both underneath the diaphragm in a very small enclosed space. Pushing down on the key lever causes the whole diaphragm with the contact attached to its underside to move down and touch the contact mounted on the base. The mechanism is well suited for situations in which a flameproof key would be necessary. Simon made the CE-613 1/2 KW antenna switch on board, upon which the WSA Co. SE-653 was used. The CE-613 was used with the 1/2 KW Type CE 859B transmitter, made by the International Radio Telegraph Co. Emil Jacob Simon himself was born in 1888 in New York City and at various times worked for Lee de Forest, the National Electric Signaling Co., and the Wireless Improvement Co. In 1915 he started making the Simon Quenched Spark System. In 1920 he founded the Intercity Radio Telegraph Co. He died in NY in 1963 and his paper collection currently resides in The Bancroft Library at UC Berkeley.
(Allgemeine Electrizitats-Gesellschaft)
ca. 1900Berlin, Germanyearly competitor for USN contracts. Key with large vertical handle, similar to drawing in Robison's manual. Also made Ruhmkorff coil with key enclosed in same box and attached ( see article by A.F.Collins). "Magnetic blow-out" to decrease spark at contacts. At least one model of the tall-handled key (probably after becoming Telefunken) uses a broad metal strap spring rather than a coil spring.
Societe Anonyme
des Condensateurs
de Trevoux
1915?Trevoux, Ain, France see "M.A.E.S.".
Societe Francaise
1910Surennes & Belfort
SFR was founded by Emile Girardeau and was under the technical direction of Mr. Bethenod. Made an oil break key similar to Ducretet & Roger. Also made the No. 234 Manipulateur Type MP oil break key(8 amp rating) and the No. 233 Manipulateur Type MC2 oil break key (30 amp rating) both as shown in 1918 SFR catalog. Type MP3 key has an articulated rear contact which can be rotated, and 3 binding posts. SFR was advertising tube gear by 1920. Perhaps along with others (CGR, Ducretet?), SFR made the Gueritot type transmitter. The Gueritot was an early airplane 50 watt spark transmitter (powered by 10 VDC) with an integrated key. Known from picture and schematic. The key and vibrator were apparently in one unit. SFR was a dominant force in the French wireless industry and built early spark sets for automobiles, pack sets for mules, wagons, and men to carry, and airplane sets. SFR made a rotary gap, a 50 KW set (1918), and a 10 KW set (blower cooled gap) among many others. 500 watt quenched gap SFR rig for seaplanes. See "Vingt-Cinq Annees de T.S.F.", published by the S.F.R. in 1935.
Societe des Telegraphes Multiplex1910FranceSTM joined SFR about 1910. STM was the maker of the "Magunna" military transmitters & receivers before and during W.W.I. The 100 watt "Magunna" pack set included an oil break key on a wooden base. STM also made the 50 watt and 800 watt Magunna transmitters. (Pictures from "Radio- électricité" Tome 1 N° 7 -December 1920"). Schematic diagrams exist for the 100-200 watt sets and the 400-800 watt sets. By 1920, STM (E. Mercadier & H. Magunna system) was advertising tube equipment.
Societe Independante de TSF (SIF)1919FranceThe fourth of the major French wireless companies-- CGR, SFR, Magunna (STM), and SIF. Founded by Robert Goldschmidt, first president was financier E. Wormser. See "de la t.s.f. a l'electronique" by A. Vasseur (in French) pg. 65. No early keys have yet surfaced, but since CGR, SFR and STM all made their own keys, it is reasonable to assume that SIF did also. A covered SIF key dated 1935 and therefore quite late to be spark is known. Initially specializing in tubes, SIF was a major manufacturer of military radio equipment in the 20's; this firm developed and built the ER series of transmitters and receivers. SIF was bought by SFR after WW2. It was still in business in 1947 with the main office in Malakoff, near Paris.
Sperry Gyroscope Company1916New YorkCS491 Relay Key for CS103 1/2 KW Motor Boat Set. Also Relay Key CS491 for 1/2 KW "aeroplane" set with aerial and reel (1916).
Stone Telegraph
& Telephone Co.
1902Maine and Boston, MAearly oil break key designed by George H. Clark; relay key; modifications of landline key for wireless. High potential key, 1907, a key the broke the secondary circuit (!) of the transformer in a spark set for the U.S. Navy. A series of contacts on hard rubber rods were actuated by solenoids and broke the secondary transformer circuit. Multiple diagrams of Stone transmitting sets show heavy duty rear contact keys in use.
Telefunken1903Germany Did not apparently label spark keys with the name "Telefunken", but spark keys were labeled with "H.T." followed by a model number and a serial number. One is a key with distinctive appearance and labeled "H.T.3" followed by a serial number; a drawing of this type of key at a station along with the schematic of the Telefunken 500 watt spark station is available7. Another model is labeled the H.T. 395 and has a self-centering ball bearing contact within cup shaped indentations in the large contacts. Simpler key called the TK. Company continued to make telegraph keys into the 1960's. In Australia, Telefunken and Marconi consolidated into Amalgamated Wireless Australasia (AWA) about 1913. AWA made keys, but a clear example of an AWA spark key has yet to surface. Relay key from USS Nebraska Telefunken system, 1907. Since 1 January 1996 TELEFUNKEN Sendertechnik is a wholly owned subsidiary of Continental Electronics Corporation of Dallas/Texas, USA. Telefunken continued to make Slaby-Arco style keys in different sizes well after merging. Also probably by Telefunken is a Reichs-Telegraphentaste-like key with large contacts. See AWA Review #2, pg 54-67 for background on Telefunken.
Tower Scientific?Boston, Mass.A huge key. One example at NE Steam and Wireless Museum. Also made economy headsets as late as 1927.
Tri-City Radio Laboratory
(aka Tri-City Radio Electric Supply Co.-- TRESCO)
1914-1924Rock Island, ILCootie key. Managed by R.K. Karlowa of Davenport, IA. See Douglas: "tri-city" refers to Davenport, IA and Rock Island and Moline, IL. Tresco also made tuners and an assortment of other radio parts.
United Wireless1906-1912New York and Seattle succeeded by Marconi Wireless Tel Co. Cross-shaped keys. Also very large operating company. Most keys were not labelled, and were therefore nearly if not impossible to tell from DeForest and Marconi keys of similar construction. Typical key was large and on a marble base, with legs protruding underneath the base. Also made at least two kinds of relay and hand key combinations. One such hand and relay key was made about 1910 on a slate base, another hand and relay key was made one or two years earlier and was labeled and on a marble base. A 32-page prospectus from 1909 was intended to lure investors. A message frank stamp for United Wireless. Pack set with standard key.
Unknown----Several interesting spark keys of unknown maker for whom further information is sought. Wooden based key with contacts in shrouds. Large slate-based key with unique lever arm. Possibly British Navy key with split lever arm and large contacts. GPO type key with heavy base. Possibly German spark key.
Vaclav Hrubyca. 1902?Prague
Small strap key on complete simple spark gap transmitter. Also made complete coherer receiver.
Wash. Navy Yard1914Wash. DC one example of diaphragm key exists made by the Radio Test Shop (Bu.S.E.). Sold at auction 10/99. Wash. Navy Yard also made the SE-59 combined buzzer and blinker practice set, and the SE-69 buzzer practice set. "The Washington Navy Yard was established on 2 October 1799, the date the property was transferred to the Navy. The yard was built under the direction of Benjamin Stoddert, the first Secretary of the Navy, under the supervision of the yard's first commandant, Commodore Thomas Tingey, who would serve in that capacity for 29 years." (from website)
Wireless Improvement Co.
(R.E.Thompson Mfg. Co.)
1912-1926+New Yorkcombined relay and hand key (1914), 5 KW rating. In Navy testing, this key beat the Lowenstein version, but was bested by WSA Co. Also made a quenched gap pack set with standard steel lever key. In 1917 was also making a 1-2 k. w. 500 cycle panel set. Col. John Firth founded the company in 1912 to make transmitters, and sold it to Thompson in mid-1917. Roy E. Thompson worked for De Forest and United Wireless from 1906-1912, then was a radio inspector for the Commerce Department (see Douglas). Joseph Freed (later of Freed-Eisemann) was ass't chief engineer for this company 1919-21. Drawing exists of a SE-68A by this company, dated September, 1918, but it is not clear any were made.
Wireless Specialty Apparatus Company (Col. John Firth)1907-1919Boston, MA In 1907, Greenleaf W. Pickard and two associates organized the Wireless Specialty Apparatus Company to market his patented detectors, one of which was called Perikon, an acronym for "perfect Pickard contact." Succeeded by United Fruit Co. Q-S-5004 (also known as the IP 109) which came in many variations including those with metal label on top or etched on side, Q-S-505, SE-68A; SE-653 (drawing for SE-653) used on 1/2 KW WSA Panel sets, very similar to the Q-S-505. 2 KW Aux. Hand Sending Key. Made relay keys as early as 1911 as evidenced by letter from Firth to Commander Todd, USN. Relay Key dated 1914 (drawing for such a key). 1 KW Flameproof Type NS 1917. A different WSA model with slender lever arm. Relay Key type Q-S-5003. Light hand key type Q-S-504, on bakelite and for use up to 6 amps. See the Old Timer's Bulletin, May, 2000, page 52. Navy SE 137B relay key which is identical to the Q-S-5003. Sometimes referred to simply as the "Wireless Specialty Company". Made the flameproof CR675 hand key for use with its CR654 and CR654A 1/2 KW quenched gap sets. Drawing for the CR6751. Made the CR681 hand key for use with 1 & 2 KW sets and used with the CR655. CR1156 hand sending key, 2KW. CR682 relay key for use with 1,2 & 5KW sets and the CR655. Relay key type QSB-5090 and Relay key type QSC-5090 with unusual shape and made for use with the 2 KW quenched gap set type QSF 2000 in 1920, as was the Control Panel Type QSF2150. 1/2 KW Flame Proof Hand Key, a diaphragm key designed in 1917 and probably same design as CR-675. Pack sets with built in key that otherwise looks to be a Q-S-505. Gorgeous antenna switch and key (IP 108) on one marble base with label.

References and notes:

1. Diaphragm keys have the contacts sheltered underneath a flameproof material in an airtight compartment. They are a bit like an oil break key without the oil and with a firmly seated cover. The Emil J. Simon CE693 1/2 KW aircraft key is the more straightforward way of making such a key. One binding post on the CE693 connects to the lever via the current strap, and the other connects to the bottom contact in the airtight compartment. The diaphragm on the Simon key is nonconducting. The Wireless Specialty Apparatus Company also made a diaphragm key, called the CR675, rated at 5 amps and 250 V. Both the CE693 and the CR675 were made in 1917. The WSA CR675 has an interesting wiring scheme, with the same idea as one of the General Radio spark keys (not a diaphragm key though). The current does not enter the lever at all, a way of protecting the operator from a dangerous shock. The only function of the lever is to carry the upper contact from which it is insulated with a sleeve. The diaphragm connects between the upper contact and the lever and the diaphragm is made of very thin sheet copper. The current goes from one binding post to the outside well of the compartment which is in contact with the diaphragm circumferentially. The current then travels through the diaphragm itself to the upper contact but never to the lever itself. Contact is made when the lever is pushed down, carrying the upper contact down onto the lower one and completing the circuit. The interesting differences between these two keys is best demonstrated by looking carefully at them, and it is a bit hard to describe in words. But it comes as a surprise when one looks at the wiring underneath the WSA key and it is obvious that the lever is not part of the circuit! Thanks to Tim Soxman who helped me work this all out.
2. "Flame proof keys were used so when damage was inflected upon a ship, tank or other radio equipped vehicles or unit, the spark from the key would not ignite the flammable vapour in the air and produce an explosion which would kill the radio operator and the other personnel in the vehicle or unit. Usually this feature was not needed, but Army and Navy found that there were some explosions caused by key sparking which resulted in needless loss of life. After all, radio should SAVE lives, not end them."
quote from email from David J. Ring, Jr.
3. A description of this key was written by Bowden Washington in an article called "Some Small Direct Current Sets" in 1916. "The pair of contacts attached to the key lever at the back, and insulated from it, are led to the antenna binding post thru a piece of Belden braid. The upper adjustable contact is connected to the antenna side of the transmitter; the contact on the base to the antenna side of the receiver. Thus the key acts as an antenna transfer switch when operated. The spring contact...opens the starting circuit ...This key, which is virtually a break-in key, is made practicable by the low potentials developed with these sets." A similar but different rear contact key was used on the Cutting and Washington 1/6 KW airplane set. These sets used a Chaffee gap to obtain "impulse" excitation, in which the gap is triggered in proper phase relation to the antenna circuit to produce almost undamped waves.
4. Probably a reference to the Navy TM Type station as used in submarines. They were made in the 1917 to 1925 timeframe and emitted 100 watts. These transmitters were originally spark transmitters and were modified into alternating current tube transmitters. This info from Howeth's "History of Communications-Electronics in the United States Navy", Appendix M, page 593.
5. See also auction catalog from Bonhams, Morse to Marconi and Scientific instruments, Thursday 3 June 2004. Beautiful color photo on page 44 of a Bing coherer and spark transmitter, circa 1905. Induction coil and key.
6. See picture in "The Vail Correspondent", No. 4, July 1993, page 17.
7. See also Text Book on Wireless Telegraphy, Rupert Stanley, 1914, Figure 97, page 174 for a Telefunken key in use with the Telefunken Type D set.
8. The Hawkhead and Dowsett book along with "The Maintenance of Wireless Telegraph Apparatus" by Percy W. Harris (also published by the Wireless Press of the Marconi House) represent the two most available sources of information about the standard Marconi spark sets. See Goodnow, A.C., "Across the Gap: An Appraisal of Spark Telegraph Engineering", The AWA Review, Vol.2, 1987, pg. 21 for a more general indepth treatment of spark sets.
9. The essential parts of a spark transmitter consist of a generator, which supplies AC power to the transformer, or a battery and interruptor for the same purpose. The power is delivered to the transformer which steps up the voltage and delivers it to the primary circuit. This power, being at low frequency and unsuitable for radio transmission, is transformed in the primary (or oscillating) circuit to radio frequency and transferred to the antenna (or radiating) circuit through the medium of the oscillation transfomer. See "Robison's Manual of Radiotelegraphy and Telephony" 6th revised edition, 1924, pg. 413.
10. Fritz Lowenstein was bidding on contracts for 5 and 10 KW Navy transmitters in June of 1911.
11. Presumably named after Andrew Gray, chief engineer of the Marconi Company in London.
12. The first known was auctioned on eBay February, 2007.
13. The following info on Phil Weingarten's machinist Hugo Picciani from Tim Patton: "On the CM 425 he made the contacts were authentic. New old stock!....All total he made 20 CM 425's, 6 Massie, and 6 Grasshopper keys."

1. Gil Schlehman, personal communications.
2. Howeth, History of Communications-Electronics in the United States Navy
3. Mayes, Wireless Communications in the United States
4. Kreuzer, The AWA Review No.9, 1995, and personal communications.
5. Lynn Burlingame, personal communications.
6. Robison, Captain S.S., Robison's Manual of Radio Telegraphy and Telephony (1918), drawing of Slaby-Arco key.
7. Department of the Navy, Bureau of Steam Engineering, Radio Telegraph Apparatus, list of type numbers RE15A105. From the Clark papers.
8. Old Familiar Strains, A Newsletter for Collectors of Radio Strain Insulators and related items, Volume 2 No.4/5, August/October 1995. History of L.S.Brach. Published by Dan Howard.
9. Robison, Admiral S.S., Robison's Manual of Radio Telegraphy and Telephony (1924), Key and Winker diagram and picture.
10. The Radio Trade Directory, May 1925, McGraw-Hill Co., Inc, NY.
11. The Illinois Secretary of State List of Domestic and Foreign Corporations, 1907-1946.
12. Anne Solberg, Senior Documentalist, Norwegian Telecom Museum, personal communications.
13. (E.C. Kilbourne).
14. W.W. Bradfield, Wireless Telegraphy for Marine Inter-Communication, "The Electrician"--Marine Issue, June 10, 1910.
15. A. Frederick Collins, THE SLABY-ARCO PORTABLE FIELD EQUIPMENT FOR WIRELESS TELEGRAPHY, Scientific American, December 28, 1901, pages 425-426.
17. Jones, E.F., "Early Military Airborne Telegraphy", in Morsum Magnificat 28, June 1993, p. 26.
18. EICO catalog, 1914.
19. "The History of General Radio from 1915-1965", A. Thiessen, courtesy of the General Radio Historical Society.
20. "Radio Manufacturers of the 1920's", Alan Douglas, 1988, all 3 volumes.
21. Lieutenant BOUILLANE, "La marine de commerce et la télégraphie sans fil" ("the merchant navy & the wireless telegraphy"), Radio- électricité" Tome 1 N° 7 -December 1920.
22. Information on A.W. Bowman from personal interview with William Bowman, son of A.W. Bowman, conducted by telephone March 1, 2003. William Bowman was 87 years old at the time.
23. Thomas Scherrer, e-mail from August 13, 2003 on the history of MP-Pedersen.
24. Hans Buhl, e-mail from August 21, 2003, curator of the science collection at the Danish Steno Museum.
25. Letters on Kilbourne & Clark history obtained from August J. Link.
26. Type Numbers U.S. Navy 1923, telegraph key sections only.
27. Denman, R.P.G., Catalogue of the Collection in the Science Museum, South Kensington, with Descriptions and Illustrations, His Majesty's Stationery Office, London, 1925.
28. Special mention should be made of the George H. Clark Radioana Collection, currently available to the public for research by appointment at the National Museum of American History, Smithsonian Institute. For info on G.H. Clark himself, see "A Tribute to George H. Clark", Tube Collectors Association Special Publication No.4.
29. Hawkhead, J.C., and Dowsett, H.M., "Handbook of Technical Instruction for Wireless Telegraphists", 2nd edition, The Wireless Press Limited, Marconi House, Strand, 1915, pp. 146-150.
30. "The Mentor" Magazine, October 1920 issue, page 38 (Lee DeForest, Dame Melba article.)

...and input from many other key collectors and friends to whom I am very grateful! Includes correspondence or help from: Tony Rogozinski, John Elwood, Neal McEwen, Jim Kreuzer, Tom French, Gil Schlehman, Lynn Burlingame, Larry Nutting, Tom Perera, Roger Reinke, Bill Holly, Joel Kosoff, Dave Pennes, Randy Cole, Pete Malvasi, Tim Patton, Paul Bock, Henry Rogers, John Firey, Mike Feher, Don Karvonen, Gerry Maira, Charlie Stinger, Mike Katzdorn, Thomas Dolph, John Casale, Doug Palmer, Jean Le Galudec, Wyn Davies, Ron McMullen, Scott Balderston, Dr. Joe Jacobs, David Crocker, Anne Solberg, Ed Gable, Bob Shrader, Stan Riome, Chuck Brydges, Jim Callow, Gregor Ulsamer, Greg Raven, Bill Burns, Fons Vanden Berghen, Bob Merriam, Hal Wallace, Elliot Sivowich, Tom Viles, Dick Benson, Harold McAleer, Yann Conan, Alain Tamburini, Thierry Ohannessian, Lee Hite and the other members of the General Radio Historical Society, Murray Willer, August Link, Jan Skoldin, Thomas Scherrer, Hans Buhl, Tim Soxman, David J. Ring, Jr., Warren Berbit, John Dilks, Ron Eveland, Mike Naruta, William Bowman, Marc Rouzet, Kevin Grimm, Eliseo IK6BAK, Jan Skoldin, Alan Larsen and many others.

Picture Credits:
Mike Feher-- PDF file of Ajax catalog, Massie leg key.
Jan Skoldin-- Elektromekano key.
Tom Perera-- CAG-457, Type 205, Massie repro, Duck Overland, RCAF, Lowenstein SE-68, Bunnell composite base, WSA mini, dime key, Leach spark relay, Telefunken H.T. 395, P. Conalb key, Clapp Eastham diaphragm key photo, Lagier
Lynn Burlingame and Jim Aguirre-- Kilbourne and Clark keys (3), Elliott ad, United Wireless on marble base, Federal Telegraph, Liberty SE-988, UW keys (3), WSA (slender arm), Little America, Blitzen ad, Federal flameproof. Burlingame apparatus, Signal Electric ad.
Neal McEwen-- TriCity Cootie, EICO, Bunnell Cootie, Leach Cootie, MP-Pedersen
Gil Schlehman-- Massie Oil Break
Ron Eveland-- Bunnell with auxilary contact
Charles Stinger-- Doron
John Elwood-- McIntosh on brown marble with label
Jim Kreuzer-- Duck catalog, Marconi, 3 Chambers pics, Murdock and EICO strap keys, Independent Wireless, Marconi 205 and catalog pic, Marconi 217 catalog pic, Marconi catalog of used equipment, 2nd Roadmap variation, CM425 blueprint, CM 408, WSA relay key, Canadian Marconi 702 and label, Federal 496 and label, Marconi SE86, Ericsson, Halcun and Gamage catalog pix, Gilbert set, S.G. Brown key, Adams-Morgan and Nichols catalog pix, Max Kohl catalog and pic, WSA diaphragm key. Marconi flatspring and oil break keys.
John Casale-- DeForest Field set photos
Gerry Maira-- 5KW Marconi, Jove Wireless Key, Mesco Hand Radio Key
Mike Katzdorn-- Wash. Navy Yard key, CR-675.
Tony Rogozinski-- Lemkuhl, McIntosh, Clapp Eastham repro, British Admiralty, Pattern, Marconi SE86
Bob Wurth-- Boston Key Jr.
Jerry Simkin-- Marconi Service News booklet (1919).
Doug Palmer-- Nanao Musen Denki, Marconi Type 701, pushpost Bunnell on composite base, MP-Pederson key, Elektromekano keys, Electric Signalling Co., C.G.R oil break key, and for taking apart his SE86 for the composite photograph!
Wyn Davies-- Admiralty Pattern keys, 365A, Brown, British Navy, Marconi 100, unknowns
Gerard Schnoebelen-- Marconi Guillotine, CGR for boats
Russ Kleinman, pictures taken at the Smithsonian Institution
Karen Blisard, pictures taken at New England Wireless and Steam Museum-- Tower Scientific, Massie keys
Jeff Carr-- United Wireless prospectus
Chuck Brydges-- Telefunken HT3, unusual CE, Massie, narrow C-E, CQ1265, Bunnell Boston key ad, MESCO 442, Young & McCombs Cootie Key, Kilbourne & Clark SE 68
Vince Thompson-- Edgcomb-Pyle
Alain Tamburini-- SFR oil break key, catalog of the Societe Anonyme des Condensateurs de Trevoux, CGR manual pic, STM oil break key, CGR 1 and 2.5 KW stations, Annaka 3 KW transmitter, Magunna 50 & 800 W transmitters, Marconi 1/2kW schematic, Magunna schematics, telefunken schematic and 500 W station drawing, STM advertisement, Gueritot transmitter & schematic, SIF key, Rouzet MS50 and AR13 pix
Eric Jackson-- United Wireless message frank stamp
John Firey-- Clapp Eastham 1/4 KW rig, BC-15A and SCR-89
Jean Le Galudec-- German airship key, M.A.E.S., V.L., French air and Navy keys
Thierry Ohannessian-- PP4 (ter), Ducretet
Thomas White webpage-- lots of info, Clark Wireless ad scan
August Link-- many Kilbourne & Clark photos
Tom French-- MESCO keying relay
Chris Lord-- Bunnell Boston pattern key
J.S. McDonald-- Bunnell without receiver shorting contact
Mike Naruta AA8K-- Robertson Clock and Instrument oil break key
Eliseo, IK6BAK-- Conalb catalog pages
Kevin Grimm-- Annaka key and label
Warren Berbit-- probably Canadian Marconi on composite base, covered SIF key
Pete Malvasi-- British spark keys (2), Massie, Telefunken, huge Massie, Tower Scientific, J4, Bunnell Straight Line, AMCO cross shaped key, EICo practice set, Clapp-Eastham variation

In cases in which only one year is noted for manufacturing dates, it usually represents the date an ad appeared in a trade journal for a key for which no other data thus far exists. Our thanks to the Smithsonian for allowing us to use some of the pictures we took there.

On the meaning of "Auxiliary": The term "auxiliary" as it referred to spark keys meant a key that was used on a transmitter for which a relay key was usually employed. It could either key the relay or be used to directly key a lower power transmitter. From the "Amateur Radio News" issue of September, 1919 (pg. 111): "This key [hand-operated key labeled as auxiliary in accompanying drawing] is furnished for emergency use. Should the relay which is controlled by an ordinary Morse key become inoperative, the operator can complete his transmission by resorting to this hand-operated large contact key until the trouble is located and remedied."

Russ Kleinman WA5Y
2nd draft October 13, 1999
Last modified: October 7, 2011

The Coherer, an Early Detector of Wireless Signals

The coherer receiver was one of the earliest ways of listening to morse code wireless signals. It was based on the discovery by Eduardo Branly that certain metal filings would conduct electricity when influenced by a wireless signal. The coherer itself was a glass tube with the air removed from it and contacts entering it from the outside. Metal filing were placed inside the coherer. Normally the filings did not conduct electricity, because the resistance across them was too high. These filings conducted electricity when a radio signal affected them and decreased their resistance. When the coherer conducted, it closed a circuit containing a sensitive electromagnet (relay) which then activated a bell or buzzer circuit. In between each clap on the bell, the coherer was struck and "decohered". This broke the circuit and the cycle repeated. In the absence of signal, nothing happened. Although Branly invented the coherer, it was Oliver Lodge who first applied the invention to practical wireless radio. Go ahead and click the "Signal" button in the demonstration above to see in slow motion how it worked!
Adapted from "Operator's Wireless Telegraph & Telephone Hand-book", by Victor H. Laughter, 1909.

Click here to see Dr. Austin's Complicated (& Obsolete!) Formula

Click here for other ideas that didn't stand the test of time!

Click here to learn about the "ether" through which radio waves were initially thought to travel

The Damped Wave

The discharge of a condenser across the spark gap of the closed oscillating circuit of a spark transmitter is similar to the action when two long glass tubes are connected by a pipe whose bore is not too small and which is fitted with a tap. When the tap is opened the water oscillates between the tubes before coming to rest. Click the tap in the connecting tube to start the action. It is similar to the Oscillogram of a spark discharge taken by Dr. Fleming about 100 years ago. Adapted from the "Text Book on Wireless Telegraphy", by Rupert Stanley, 1914.

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