Radio Boulevard
Western Historic Radio Museum

Radio Telegraphy -  From Straight Keys to Bugs

Contents of Part 1

Straight Keys -
Spark Keys, Radio Hand Keys, Military Hand Keys, Flame-Proof Keys

Semi-Automatic Keys (Bugs) - The Vibroplex Company, Standard and Deluxe Models - 1912-1960

Contents of Part 2

Semi-Automatic Keys (Bugs) - Signal Corps J-36, Speed Bug, Buzza,
Speed-X (Electro Mfg, Stewart Johnson, Les Logan, E.F. Johnson,) McElroy Mfg Co.,
 73, Kenco, Dow-Key, Cedar Rapids Bug, Hi-Mound -   1926-1960

Learning Tools -  Marconi Code Course, Oscillators, Instructographs

Wire Telegraphy - Small sample of some Land Line and Wire Telegraph gear

by: Henry Rogers WA7YBS/WHRM


International Morse Code School - U.S. Army-style





Military Semi-Automatic Keys

Signal Corps U.S. Army - Key Type J-36

Contractors:  The Vibroplex Co.,  The Lionel Corp.,   J.H.Bunnell & Co.,   Buzza Products,   Brooklyn Metal Stamping Corp.

The Signal Corps' identification "J-36" was applied to all semi-automatic keys regardless of the contractor or the minor details of construction.

As early as 1930, the U.S. Army Signal Corps began ordering semi-automatic telegraph keys for various uses. The earliest contract appears to have been with the Brooklyn Metal Stamping Corporation who supplied the Army with their "Speed Bug" with the military data plate being about the only change to their standard bug. Although the tag has "Speed Bug" on it, "J-36" is also present.

Vibroplex J-36 - Vibroplex began supplying the Army with a speed key that was based on their Lightning Bug around 1935. Except for the data plate, Vibroplex's J-36 is identical to their standard, late-thirties Lightning Bug.

The photo to the left shows a pre-war Vibroplex J-36 from Order No. 2844-N.Y.-40. Dated 5-4-40 - Serial Number 548. This J-36 data plate has the 796 Fulton St., Brooklyn, NY address typically found on pre-war J-36 keys. With some contracts during WWII, the 833 Broadway, New York, NY address was used on the J-36 data plates. There are a few other variations that can be found on different Vibroplex J-36 data plates. The data plates were originally nickel plated brass with the field painted black resulting in the data plate having silver lettering on a black background. Many data plates appear brass-colored because of wear or corrosion and it's possible, with all of the variations, that some data plates might have been unplated brass with a black field.

Bunnell J-36 - During WWII, the J-36 production demand required additional contractors. J.H. Bunnell & Company produced two types of J-36 bugs. One that uses a main frame that looks something like the smaller Speed-X frame and a damper that's similar to the Speed-x along with a pendulum and weight similar to theVibroplex Lightning Bug. The second type Bunnell is similar but uses a short Vibroplex Original style frame and damper style. The photo to the right shows the Bunnell version of the J-36 with the "Speed-X-style" frame and damper from about 1943. The Order is dated 8-1-42 but the Order No. 8001-Phila-43 has 1943 embedded in it. Serial number on this Bunnell J-36 is sn: 125. Note that the shorting lever knob is vertical on the Bunnell but horizontal on the Vibroplex and the Lionel. Also note that the base bottom edge has casting roughness that wasn't removed before painting. The entire base is a fairly rough cast and also is heavier and thicker than the Vibroplex or Lionel versions. Also note that the top edge of the base has a pronounced bevel. The data plates on the Bunnell J-36 tend to spot and corrode more than one would expect.

Lionel J-36 - Perhaps the greatest quantity of J-36 keys was built by the Lionel Corporation during WWII (shown below-left.) Their version is very close to the Vibroplex Lightning Bug with the only significant difference being the rounded paddle rather than the standard triangular paddle. The plastic identification tag on all Lionel J-36 bugs is always in poor condition with the example shown in the photo being typical of the "better" condition tags (at least it's there.) The plastic was prone to shrinkage and usually pulls away from the mounting pins and breaks. A lot of J-36s are missing their tags entirely. Fortunately, repro tag artwork is available online. Artwork for the Lionel tag is at  proper sizing, printing and plastic lamination will be required.

J-36s are great keys to use and provide good action and precise sending. Most J-36 keys will require some rebuilding to function at the level the design is capable of. The Lionel J-36 shown to the left belonged to W3ON.

Just about the only bug I've heard being used "on the air" in the past several years have been the J-36. Their military connection has provided a place to use a J-36 on some of the vintage military nets that allow some CW operations. The Vintage Military Radio Net, operating on 3.974mc, allows our "73 round" to be sent in CW if the operator has the equipment and wants to exercise his fist. The Military Radio Collector's Group, operating on 3.985kc, calls for CW stations at the end of the first acknowledgement of the phone check-ins.

In addition to Vibroplex, Bunnell, Lionel and the Brooklyn Metal Stamping as contractors for J-36 keys it appears that Buzza Products of Australia also had a contract for J-36 keys during WWII. The Buzza version was very similar to the Vibroplex Lightning Bug.

The Brooklyn Metal Stamping Corp. "Speed Bug" and the Buzza Products No. 100 Key are profiled next.




Brooklyn Metal Stamping Corp.



Brooklyn Metal Stamping Corporation was in business from 1930 up to the beginning of WWII. They were probably licensed by Albright-Vibroplex to build this "knock off" because many of the parts are identical to those built by Vibroplex. The "Speed-Bug" mainframe is an exact copy of the Vibroplex. The only significant non-Vibroplex features are that the vertical dot spring contact being "keyed" to only allow mounting in the odd vertical position and the elaborate spring-loaded ball contact damper. A somewhat significant difference is the much longer main spring (the blade spring that connects the main lever to the pendulum rod.) This long, flexible main spring results in a very slow speed with the single weight at the end of the pendulum. Normal sending speeds require the weight to be almost as far forward as the adjustment allows. Probably dates from the mid-thirties.

Brooklyn Metal Stamping Corp. was the first contractor to supply J-36 speed keys to the Signal Corps prior to WWII (early thirties.) The BMS J-36 is identical to their standard "Speed-Bug" (the bug shown in the photo) with the exception of the data plate.


Buzza Products

Automatic Key No. 100


This Australian-made key is based on the Vibroplex Lightning Bug design but changes the support of the dash lever by providing it with its own pivot and bearing. The damper also departs from the Lightning Bug design, requiring fewer parts. All No.100 Buzza keys have a red paddle and a black knob. A very heavy base makes the Buzza a sturdy key to operate and its dot action is very precise. Dates from WWII.

Buzza Products was a contractor during WWII for the J-36 military "Lightning Bug" version. Buzza's J-36 has an appearance that is similar to the Vibroplex or Lionel versions of the J-36, that is, having the damper suspended from a horizontal strap mounted to two vertical round stand-offs. Typical of Buzza though, the paddle will be red and the knob will be black. 




The Vibroplex Company

WWII Deluxe Original

There are two possible reasons that the Deluxe Originals were built with dark gray painted bases during WWII. First would be that several different types of materials were required for war production needs and Chromium was one such material. To help the war effort and conserve the use of chrome Vibroplex produced the Deluxe Original with a dark gray wrinkle finished base to replace the usual chrome-plated base. If this was the case though, why just the base? Why not all of the chrome plating?

The second possible reason is a belief that was promoted by Ted McElroy that the glare from chrome-plated key bases caused operator fatigue and resulted in sending errors. Well, that was McElroy's belief and certainly a glaring chrome key might have its drawbacks in a military radio room during wartime.

With the WWII Deluxe Originals the red knob and paddle along with the jewel bearings were still retained. Since these keys date from before the jewel bearing update of 1948, the old style top bearing adjustment was still "in use" on these keys. Though the top bearing appears like the standard type bearing it actually has the jewel mounted into the bottom of the threaded shaft. The same type of jewel bearing is also used for the bottom trunnion bearing. Since the jewels are non-conductive, two thin copper braids are used for grounding the main lever. The braids are attached to the lever and at the front of the main bearing support using small machine screws.

Whatever the reason for the painted base, immediately after WWII ended, Vibroplex returned to the chrome plated base on the Deluxe Original.




Electro Mfg. Co.     -     Speed-X Radio Mfg. Co.     -     Speed-X Mfg. Co. (Les Logan Co.)      -     Speed-X (E. F. Johnson Co.)

Electro-Bug from Fresno   ca: 1928



The "Speed-X" name can trace its origin to Electro Mfg. Co. located in Fresno, California. Electro Mfg. Co. produced the Electro-Bug. Its design used an electromagnet that was powered by the voltage present on the keying line. The initial design intended the voltage source to be the voltage on the land line circuit. Later users, like radio hams, could use the voltage from their transmitter keying bias or a transmitter keying relay voltage. The dash contact is directly operated however the dot contact is wired through the electromagnet. When the dot lever on the key was closed, the keying line current flowed through the electromagnet and the magnetic attraction pulled the pendulum weights away from the dot contact point which broke the current flow releasing the magnetic attraction and allowing the dot contact points to again close which again caused current to flow in the electromagnet, attracting the pendulum weights, breaking the dot contact, etc., etc., repeating this movement as long as the dot lever was held in position. The "making and breaking" of the electromagnet current intensified the movement of the pendulum, producing a firmer dot contact pressure that seemed to continue on for as long as the key lever was held in the dot position.

Electro-Bug from San Francisco  ca: 1932


A variable contact-point resistance was wired as a shunt (in parallel) with the dot contact to base to provide an adjustment to the intensity of the dot action for the user's preference. The foremost contact was a "closed" position. The rearmost contact was no voltage to the electromagnet so the key was essentially like an Electro-Bug Junior. The next position forward was full voltage on the electromagnet. Each of the next successively forward positions reduced the amount of current that flowed through the electromagnet. This allowed the user to adjust the electromagnet response to whatever voltage was riding on the keying line.

The Electro Mfg. Co. started out in Fresno, California in the mid-1920s. They produced the Electro-Bug and also the Electro-Bug Junior (that didn't have the electromagnet.) Most Fresno-built Electro-Bugs date from the mid-to-late-twenties. Although the name "Speed-X" doesn't appear on any of the Electro-Bugs, much of the hardware is very similar to later Speed-X bugs. Especially noting the "T" frame and the damper style. Stewart Johnson (aka Steward Johnson and also Stewart "Red" Johnson) became associated with Electro Mfg. Co. around 1930. He purchased the company while it was located in Fresno and subsequently moved it to San Francisco. Johnson continued to build Electro-Bugs in San Francisco for a short time, probably into the early thirties. By 1934, Johnson was producing a fairly standard semi-automatic bug that was "Distributed by the San Francisco Radio Exchange" according to the tag mounted on the key base. Around the same time (1934,) Johnson changed the name of Electro Mfg. Co. to Speed-X Radio Mfg. Co. The design of the keys also changed becoming a very standard semi-automatic key based on the Vibroplex Single Lever design and resembling the Blue Racer in size. 

Shown to the lower right are close-ups of the two metal tags from the two Electro-Bug keys shown above. The left photo shows the Fresno tag and the right photo shows the San Francisco tag.

Experimental Test of the Electro-Bug - I wondered how well the electromagnet enhancement for the dot stream worked. I noticed that on the SF E-Bug the electromagnet had been disconnected and a jumper soldered underneath. I tested the electromagnet solenoid and its DC resistance measured 98 ohms. I reconnected it to the input terminal and removed the jumper from underneath. I connected a variable DC power supply to the terminals to simulate a line bias level. I started with +15vdc and set the adjustable lever on the bug midway (50% current though the electromagnet.) When operating the dash lever, the key just loaded down the power supply (as would be expected.) But, when the dot lever was operated the pendulum action was impressive. Very forceful with good dot action. It seems like the dot string will continue for as long as the key lever is held in the dot position. I tested the range of DCV that seemed to work and found about +6vdc to +15vdc seemed correct. Around +10vdc seems to work best allowing an adjustment range that seems usable. This voltage range seems to indicate the Electro-Bug could work directly with a blocked-grid type of keying system. Also, a keying relay system would allow cathode keying operation on higher power PA stages. Keying landlines would depend on the line voltage and number of stations connected.


Speed-X Radio Mfg. Co.

Stewart Johnson

Stewart Johnson had changed the name of the Electro Mfg. Co. to Speed-X Radio Mfg. Co. sometime after he moved "Electro" from Fresno to San Francisco. The company's new address was 30 Ninth St. in San Francisco. Johnson stopped building the Electro-Bug (probably around 1932) and started to produce a much less complicated to build and less problematic to operate type of semi-automatic key. Early Speed-X bugs will have a label indicating they were "Distributed by the San Francisco Radio Exchange" and will have a somewhat different type of front-mounted bearing support on the main frame. This bug was redesigned to be a very close copy of a standard Vibroplex Single Lever although more like the Blue Racer in size. This new design bug was called "Speed-X Hi-Speed Key." Johnson produced these type of Speed-X keys from around 1934 until he sold a partnership in his company to Les Logan in 1937.

The Speed-X shown is the later version bug. These Stewart Johnson Speed-X keys have no identification at all. It's small size is comparable to the later Les Logan Model 515 Speed-X (or the Vibroplex Blue Racer.) Even though there's no identification on this bug, it was found in unused condition in its original Stewart Johnson Speed-X box.


Speed-X Radio Mfg. Co.

Stewart Johnson

This is another Stewart Johnson Speed-X bug. This one is nickel-plated and, typical of the later Stewart Johnson versions, this one doesn't have any sort of identification. However, one can see the similarities that this key has to all early Speed-X bugs and particularly those built by Stewart Johnson. It seems to be fairly common that there are minor variations in Stewart Johnson keys. Note that the damper is very similar (but not identical) to the key shown above. The shorting lever is slightly different. The cast feet are quite different. However, there are many other pieces that are identical to Stewart Johnson keys.

A major help in identification and dating this key comes from its former owner, Al Norberg W6HLJ, who has owned this key from 1935 until recently (well, 2013.) Since this key was used with Norberg's homebrew transmitter that he built in Manteca, California, in 1935, this key is, more than likely, a Stewart Johnson version Speed-X. At 97 (in 2013,) Al Norberg donated his Speed-X key to go along with his homebrew transmitter that he donated to the museum several years earlier.

For more information on Al Norberg's homebrew 1KW (CW only) transmitter built in 1935, go to "Classic Pre-WWII Ham Gear - Part 1" for a complete write up that includes two B&W photos taken in 1936 showing the transmitter, homebrew receiver and this key. Go to Home/Index for Navigation.


Les Logan Co. -  Speed-X Mfg. Co.

Model 500

Les Logan had an electronics salvage business in San Francisco in the mid-thirties. In 1937, he bought into a partnership with Stewart Johnson and became the "salesman" while Johnson ran the company. Within a short time, Les Logan Co. had bought the entire Speed-X Radio Mfg. Co. from Stewart Johnson. Logan dropped "Radio" from the name, changing it to Speed-X Mfg. Co. and the location was moved to 646 Jessie St. in San Francisco (one of several locations the company had in San Francisco over the years.) Though there certainly was a "Speed-X Mfg. Co.," that name never appears on any of the key's metal tag. Advertising and boxes used "Speed-X Mfg. Co." but "Les Logan Co" is on the key identification tag. Les Logan was involved with Speed-X telegraph keys from 1937 up to 1947. Logan was a former machinist, shipboard radio operator and incessant tinkerer so the keys underwent some major changes with Logan running things. Logan finally added an identification tag to his keys along with a model number (early models also had serial numbers.) Logan's bugs use two paddles rather than a knob and paddle combination. He also offered a couple of different types of bearing support frames on his different models. Logan changed the frames of his keys to pot metal castings. By the late-thirties, the procedure for casting pot metal had improved dramatically from a decade earlier. Logan re-introduced the "T" handle that had been used on the earlier Electro-Bug but was absent from Stewart Johnson's keys from 1934 until 1937. This Model 500 belonged to W3ON.


Les Logan Co. - Speed-X Mfg. Co.

Model 501

Les Logan Co. continued to build various telegraph items during WWII. At one time most of Logan's family also worked building and selling keys and other telegraph items. After WWII, Les Logan Company became a sales representative for many other companies, including E.F. Johnson. In 1947, Logan sold the Speed-X Mfg. Co. to E.F. Johnson. Les Logan Co. continued on as a sales rep for several other companies for another couple of decades.

The Speed-X Model 501 was the nickel-plated version of the Model 500. The "T" handle was available on the larger Logan bugs and supposedly allowed the user to set the bug on its side and use the dash paddle as a straight key. Most Logan keys will have excellent condition bases but the "T" handles usually show some plating defects due to the pot metal casting. However, poor storage, especially in unheated sheds or garages in humid areas, seems to have caused the majority of the condition problems that we find today on both the frames and the bases. This Model 501 dates from the late-thirties or early forties.

Les Logan around 1940


Les Logan Co. - Speed-X Mfg. Co.


Model 510

The Model 510 was Les Logan's very small key that was priced well-below the larger 500 models. The base of the 510 is cast pot metal which greatly reduced the weight of the key. Additional weight was removed by recessing the bottom of the base, making it somewhat hollow-like. The light-weight of the bug probably prompted its nickname, "pocket key." Due to the thin edges on the recessed bottom of the base, there is some minor stress corrosion of the pot metal. While the minor cracking is noticeable, the pot metal isn't fracturing or showing any other signs of "pot metal disease." For painted surfaces, the pot metal of the time was usually adequate but, for nickel-plating, the pot metal surface was a poor choice due to its unstable nature. This Model 510 belonged to K6QY.


Les Logan Co. - Speed-X Mfg. Co.


Model 515

The Model 515 was Les Logan's big seller. It's the standard key that was probably priced very competitively and therefore became very popular. The Model 515 was slightly larger than Vibroplex's Blue Racer but, unlike the Racer, the 515 can send fairly slow Morse. The reason is because of the longer main spring used. The main spring is the spring-blade that connects the pendulum rod to the main lever. The thickness and the length of the main spring will determine the flexibility of the pendulum and therefore the slowest sending speed that can be achieved with the given weights. This photo shows the "double-line circles" or "bull's eye" pattern that was on all of the fiber paddles used on Les Logan's keys. This Model 515 belonged to W6EYC.


E. F. Johnson Company

Speed-X  Semi-Automatic Key

CAT. NO. 114-501

E. F. Johnson Company of Waseca, Minnesota became the last manufacturer using the Speed-X name on a bug. Johnson purchased Speed-X from Les Logan in 1947 and initially continued to produce basically the same type of keys. Eventually, a different weight design was used followed by a change in the fiber paddles to plastic. The last of the Johnson Speed-X bugs have chrome plating, different tags (that mounted on the T-bar) and other minor hardware changes. The bug shown probably dates from the early 1950s. This bug belonged to K6QY.


E. F. Johnson Company

Speed-X  Semi-Automatic Key

CAT. NO. 114-500

The Cat. No. 114-500 was the standard version of the plated bug shown above. The base and frame are painted black wrinkle finish and the hardware is chrome plated. This Speed-X key was found in its original box in unused condition - the two paddles weren't even mounted to the lever. What was interesting was where I found the key. I always have made it a point to go to the Hot August Nights annual car swap meet held in Reno. I even went to it when it was called Harrah's Auto Swap. Hot August Nights has always seemed to produce something radio related over the years. I've found several telegraph keys there many times. Well, this Johnson 114-500 was at a HAN swap probably around 1995 or so. I had actually been through the entire swap and was standing beside a table that I thought I had already looked at. I was thinking if there was anywhere else to look in the swap area. I happened to look directly down at the table that I was standing right next to and I saw a familiar-looking orange box with a blue label. I wondered if the bug was actually inside. I was amazed when opening the box I found that the bug was untouched, never used, in mint condition. I didn't even have to ask the dealer what the price was, he came over and volunteered that information. Money quickly exchanged hands ($30) and I had the bug.

At home, I mounted the paddles with the hardware provided in the box. Unusual that the bug was never used and is still pretty much that way.


E. F. Johnson Company

Speed-X  Semi-Automatic Key

CAT. NO. 114-520


This is Johnson's version of the old Les Logan Model 515. This particular example has the later plastic paddles installed. Also, note the phillips head screws. This bug probably dates from the late-fifties up to the mid-sixties.

When E.F. Johnson sold Speed-X to the Wm. Nye Co. (Nye-Viking) in 1972, the tooling for hand keys was included in the purchase. For some reason, the tooling necessary to build semi-automatic keys wasn't. It's also possible that Nye just didn't want the bug tooling. He probably felt that, by 1972, with the ever growing popularity of electronic keyers, the market for bugs just wasn't enough to warrant the set-up of the tooling necessary to produce a product that wouldn't sell all that well. In any event, Nye continued to offer "Speed-X" hand keys for awhile. Eventually, the "Speed-X" name was dropped and the keys became Nye-Viking keys. Wm. Nye Co. started in 1972 in Seattle but eventually moved to Idaho.



McElroy Manufacturing Corp., aka: T. R. McElroy "World's Champion Radio Telegrapher"

Deluxe Model MAC Key

Ted McElroy was a champion radio telegrapher having gone through the Candler system of learning International Morse code. His receiving speed was advertised as 55wpm in the mid-thirties but ultimately Ted was clocked at over 70wpm.

McElroy's connection with high-speed CW led to his forming a company that specialized in various types of code equipment manufactured between the mid-thirties thru WWII and for a short time after the war. Ted's company seems to officially have been "McElroy Manufacturing Corporation" (officially formed in 1941) but most of his earlier telegraph key name-plates will have "T. R. McElroy - World's Champion Radio Telegrapher - Boston Mass." as the company name. Sometimes "MAC" also appears on the name-plates. Around 1955, McElroy sold his business to Telegraph Apparatus Corp. (T.A.C.)

In 1937, McElroy began producing the MAC key. It used a heavy cast iron base that featured a "T bar" frame. Supposedly, the key could be turned on its side and used as a hand key. The damper utilized a loosely mounted thick metal disk and arm that was adjustable in height. The MAC keys were available in black wrinkle finish and the Deluxe versions had a "marble" finish.

The metal identification plate on the Deluxe Mac Key reads:

Radio Telegraph Transmitting Key
(Deluxe Model Mac Key)
Mfd. by
Theodore R. McElroy
World's Champion Radio Telegrapher
Boston, Mass, USA
Speed Key Serial No. 1377 

Some of the Deluxe MAC keys will have a dot-spring pre-load installed. This adjustment would "load" the dot spring to have more "stiffness" and reduce contact bounce. The Dot Spring Pre-Load is shown in the close-up photo to the left. Note that the rod is adjusted to slightly compress the spring which will reduce its flexibility making the dot contact less likely to bounce and result in more precise dot streams.

The Deluxe Mac Keys were made in this style with the metal identification plate from around 1937 up to about 1940.

photo right shows Ted McElroy around 1940


DeLuxe Model 600

The Deluxe Model 600 shown features the same type of "marbled" finish that was found on the earlier versions of this key. The marble finish resulted in a key that was striking in appearance and the finish was very durable.

This version of the Deluxe MAC key started to be produced around 1940. The decal labels replaced the large metal identification plate used on the earlier MAC keys. Also, the dot spring pre-load is usually not found on these later keys. The Deluxe Model 600 sold for $9.50 in 1940.

All of the McElroy MAC keys are heavy, well-built units. Key contacts are large and all of the hardware is heavy-duty. When in good condition and well-adjusted, the Deluxe MAC Keys have a comfortable action and can send CW very accurately.

McElroy also manufactured various types of hand keys (see the McElroy Stream hand key in the Hand Key section above.)


Model S-600 "Super Stream"

Ted McElroy's "Stream" keys featured a Zephyr-styled, "teardrop" shaped base that evoked the era of speed and rapid movement. Both the "Stream" hand-key versions and the "Super Stream" semi-automatic key used this style base. Introduced around 1941, the S-600 was chrome plated as were some of the "Stream" hand-keys.

The Super Stream was given the model number S-600 but it isn't located on the tag or anywhere on the bug. The name Super Stream doesn't appear on the tag either.

The Super Stream S-600 appears small in photographs but the key is quite large and very heavy which helps it stay in place when sending. It's a stunning key that, if adjusted properly, has a wide-range of sending speed and is comfortable to operate while providing a very precise dot-action. The fact that the key "stays put" on the bench really helps sending accuracy. Of course, any bug could be mounted to the bench with screws to keep it from moving around but the Super Stream S-600 does so just by having most of its weight at the front of the base. 



Other Bug Manufacturers

Ultimate Transmitter Company


Ultimate Transmitter Company was located in Los Angeles, California. Their semi-automatic keys were merely called "73." These bugs are very small and work by way of a bell-crank that allows actuating the vibrating pendulum from a right-angle mounted key lever. The left lever can actually accomplish automatic dots when pressed to the right and manual dashes when pressed to the left. If the user wanted the feel of dual levers then the right lever when pressed to the left will also accomplish manual dashes. The wedge and cable are attached inside under the base plate. The side lever provides a "closed key" for transmitter adjustment. The "73" keys were made in the 1920s and the patent date on both examples shown is "6-23-25."

Ultimate Transmitter Co.  "73"  Example No.1

Unfortunately for collectors, the "73" bugs were built on pot-metal bases with pot-metal upper cover and lower sub-base. During the 1920s, the pot-metal process was primitive and contamination of the mix affected nearly all pot metal cast products. The material degraded rapidly with a process called "stress corrosion." The result was warping, chipping, cracking, distortions,...on and on. Adjustments are accessed inside the key mechanism after lifting off the metal cover. The inside screws adjustments that are threaded in pot metal are usually "frozen" and, if forced, the pot metal will break. Adjustments threaded into nickel plated brass parts are usually not "frozen."  Be sure to loosen any jam nuts before trying any adjustments.

Note the cover on the "73" bug shown in photo left (Example No. 1.) Large chips are obvious and also note the cracking on the base and the stress cracks all over the top of the cover. Almost all paint is gone from this example. Nearly all pot-metal made in the 1920s will today be found to be victims of stress corrosion. As can be seen, this example of the "73" bug is a victim of severe "pot-metal disease" that not only affects the top cover and base but also affects the pot metal sub-base that the key mechanism is mounted to. The distortion is not too obvious at the angle of photo right but the "bent" sub-base doesn't allow the mechanism to be in alignment and therefore accurate adjustment is not possible and this means the key really doesn't send properly - or, at least as well as the "73" bugs did when they were new. The dash lever is missing and the secondary dash contact broken off on this example also. Since the dash level is missing, so is the dash paddle.

Inside Example No. 1

"73" Bug   Example No. 2

The second example shown in the photo left still has its original blue paint and only minor damage to the top cover. The dash paddle was broken and remounted with a different screw hole resulting in its shorter length. Inside has suffered a bit more with a severe warping of the secondary dash contact mount. Also, in this "73" the dot contact mount was broken but luckily the broken piece was saved and repair was possible. There appears to have been a divider between the two levers that was part of the top cover but that must have been one of the first things to break (broken on both examples.)

The "73" bug was a very clever design that probably worked very well when the keys were new. Unfortunately, the material used for their construction was not stable and that resulted in a short useful life for the key. That's probably why the "73" bug has a relatively "unknown" status today.

Inside Example No. 2


The Kenmore Company

Kenco "Bug" Key

The Kenmore Company was located in Boston, Massachusetts. They built a couple of types of semi-automatic keys that were sold through Boston's "The Radio Shack" store. Boston's "The Radio Shack" was a large ham radio dealer, selling all types of ham gear from new and used receivers and transmitters to all types of radio accessories. The Kenco Key was an inexpensive bug that was built onto a 0.125" thick piece of black formica. All of the key components mount to this thin formica platform that is in turn mounted with four screws to a cast iron, welled, base. The "well" of the base allows for clearance for the wiring of the dot and dash contacts to the connection terminals all accomplished under the bakelite platform. The Kenco Key has two levers. The dash lever operates directly while the dot lever is operated by the dash lever pressed in the opposite direction. Each lever has its own bearings. The main frame, damper, dash contact mount and dot contact mount are all made from cast pot metal that's painted black wrinkle finish. The pendulum rod is extended past the damper allowing the weight (or weights) to be placed at the end of the pendulum rod (providing very slow dot action) or in front of the damper for faster speed.   >>>

>>>  The key came with two weights that usually had one placed on each side of the damper. Despite its rather cheap construction the Kenco Key does send very good Morse and it's comfortable to use (as the ad implies.) Kenco Keys date from the late-thirties up to about WWII. Selling price was $3.45 in 1938. Ad from QST January 1938.


The Dow-Key Company

Deluxe Universal "Rotary" Speed Key

Paul Dow began making bugs around 1942 in Winnipeg, Manitoba, Canada. Dow felt that the speed keys that were then available didn't offer any adjustability to the angle of lever, knob and paddle since all keys had this mechanism in a fixed-vertical position. In Dow's opinion, this made those speed keys uncomfortable to use for long sending sessions. Dow soon was producing a "Bent Key" that had the main frame mounted at a slanting angle to have the lever, knob and paddle at an angle that was hopefully more comfortable for the operator. However, the Bent Key's angle wasn't adjustable to individual preference. By 1949, Dow had patented his Universal "Rotary Key" that allowed full adjustment of the lever, knob and paddle position angle to either side from vertical. One could also adjust the vertical angle of the paddle. The complete adjustability of the Universal allowed the user to find the perfect "fit" for his (or her) sending hand.  The Dow-Key Universal was built in Winnipeg for a few years although the last advertisement in QST was in September 1951. Many early magazine ads show a Warren, Minnesota address along with the Winnipeg address. >>>

>>>    A few years later and the keys were carrying tags indicating they were made in Warren, Minnesota with Winnipeg listed as the distributor for Canada. Paul Dow retired in 1956, leaving the operation of Dow-Key to his son, Gordon. Paul Dow died in 1957 and in the same year, Gordon moved the company to Thief River Falls, Minnesota. 1957 was also the last year that Dow Key made speed keys. The Dow-Key Company had been slowly changing and adding to the product-line with RF switches becoming their specialty. The Dow-Key coaxial relays are probably the best known to hams of these types of products. Dow- Key has had several owners but is still in business building various types of RF switching devices.

How it Works - The Universal Rotary Key uses a tubular, flanged housing in which the main lever is mounted. The trunnion bearings are adjustable both top and bottom. Once the main lever is mounted in the tubular flanged housing this assembly can be inserted from the backside though the vertical base mount and lightly secured with the knurled thumb screw. Then the red plastic retaining ring with dash contact mount is placed over the protruding portion of the flanged housing. The red plastic retaining ring is secured by lightly tightening the two philips head screws. To rotate the entire flanged housing and main lever the knurled thumb screw is loosened and the mechanism rotated to the desired angle and then the thumb screw lightly tightened to secure that position. Note that the dot contact is mounted with a clear plastic standoff on the backside of the flanged housing. Note that the connections to the dot and dash contacts are via flexible wires. This is to allow unhindered rotation of the mechanism. Total movement is about 270 with vertical being the halfway point. Though it's possible to rotate the mechanism all the way CCW and maybe use the dash contact side as a straight key, the mechanical limits don't allow rotation to a completely horizontal position. Besides, it was never the intent of the Universal to double as a straight key. A fully adjustable, comfortable-to-use, speed key were the design goals of the Universal.

The Deluxe Universal Rotary Key shown is from the very early fifties. It has a tag indicating that it was built in Winnipeg, Canada. The Deluxe Universal is a striking key with its transparent red plastic, transparent clear plastic and chrome features. The precise machining of the various pieces results in a very smooth rotation when adjusting the sending angle. The Dow-Key Deluxe Universal has a very wide range of speed and, since it can be set up to any angle of operation, it's the ultimate in sending comfort. I've tried different angles and Paul Dow was actually "on to something." For me, a slight angle CCW does feel nice. You do have to readjust the contacts slightly if the angle change is dramatic but it's not necessary for small changes. I've noticed that sometimes one will see a standard bug that has a slight "twist" in the front part of the lever (like the Buzza.) I guess that was one way to get a comfortable feel.


Electrical Specialty Mfg.

 "Cedar Rapids Bug"

Electrical Specialty Manufacturing started making bugs in 1936. The company was located in Cedar Rapids, Iowa which has resulted in their key being given the nickname "Cedar Rapids Bug." Electrical Specialty's methods of manufacture and their parts didn't change a lot over the years. Minor changes the damper design and in the cast base having four feet on early versions and five feet on later versions are the most often cited.  The rubber bumper on the damper is another unusual feature. The company name is cast into the bottom of the base. The Cedar Rapids Bug was perhaps the only semi-automatic key that was offered either in assembled form or as a kit, (the price difference was minimal.) Since many were assembled from kits, builders sometimes took liberties with custom paint jobs and special hardware. The example shown in the photo is the "standard" Cedar Rapids Bug (ca. 1947.) Electrical Specialty is still in business but they quit making bugs in 1957. 

NOTE: The paddle looks squared-off and unfinished but this is an original paddle and knob and shows how the standard models looked assembled without modifications. Of course, since these bugs were kits, original owners might have "shaped" the paddle to their preference or added other "custom" features to the bug.  


Dentsu-Seiki - HI-MOUND BK-100
a.k.a. Skillman, Calrad TK-12, Monarch KY-102 and many other names

This type of bug was sold under many different names by several different dealers including many of the catalog dealers, like Lafayette or Allied. The Japanese company Dentsu-Seiki was the probable manufacturer of the keys. Dentsu-Seiki did change their name to Hi-Mound but other names like Monarch, Skillman and Calrad were used by the various dealers. The Calrad version was identified as "T.K.12" on the packaging. Monarch's key was identified as "KY-102." Hi-Mound was the BK-100 (photo right) when sold by Lafayette. The BK-100 does have a rubber "suction cup" (full size) base pad that adheres to table surfaces quite well. Skillman was one of the few versions with a name on the plastic cover (the only one I've seen.) Most versions will not have any name on the cover or the key. These bugs do seem to function quite well although the adjustments are a little hard to get at. Also, many of the plastic covers were fragile and most, if even present, will be found in poor condition with scratches, cracks or broken pieces.



Telegraph Accessories - Learning Tools

Victor Talking Machine Company

Marconi-Victor Course - Wireless Telegraphy

When the USA became involved in WWI (April 1917) the Army and Navy realized they were going to need wireless operators in the field and on ships at sea besides the trenches. Training time would be shortened if the men enlisting already knew International Morse Code. What better way to learn the code at home than by phonograph record. The Victor Talking Machine Company offered a six record set along with booklet in 1917 to assist the military in providing a method to have future enlistees already know the code. The records are 10" diameter and are acoustically recorded, that is, all the speaking and the code "buzzer" were performed before a large horn that directed the sound energy down to a record cutter that made the master. The sound of the transmitted code signals sounds like a rotary spark gap type transmitter but is probably a large mechanical buzzer. In the first record for learning the alphabet, the announcer yells "A" and then the buzzer is heard to send "dit dah" at about a ten wpm speed. Then the announcer yells "B" - "dah dit dit dit" from the buzzer. This same format is used for learning the letters and numbers. The records progress from learning the code on the first record and then on to building speed up to full messages sent on the last record.

Recordings have been used to learn International Morse for years after this Marconi-Victor course. Several companies issued records over the years. Many hams remember the Ameco Code Course records. When I was a teenager, I learned the code from an Ameco Code Course LP record that I checked out of the local library. The recording medium went to tapes and then CDs. Computer programs have also been instrumental in instruction and building code speed.

Learning to receive International Morse was certainly the most difficult part of the task. But, learning to send Morse and to be able to "handle a key" was also very important. It required tools like the following equipment.


Code Practice Oscillators

Insuline Corporation of America - Signa-Tone

Bud Industries - Audio Oscillator

Code Practice Oscillators were used for several purposes. First, when two or more people were trying to learn the code or were trying to improve their sending ability, the Code Oscillator allowed one person to send while the other received. The positions would be switched after a while to allow both individuals to send and receive. Unlike the buzzer practice sets, the Code Oscillators sounded more like a true CW signal (well, it depended on the oscillator) and probably made the transition to an actual "on the air" copy easier.

These Code Oscillators could also usually be connected to the ham transmitter to act as a sending monitor - to make sure that your sent CW had the proper spacing and rhythm. The tube used was generally a 117L6 which was a diode rectifier and pentode in one envelope. Usually the speaker was a Hi-Z armature-pin speaker. Most had the option of using a headset for monitoring. Pitch of the tone was adjustable.

Another use for the Code Practice Oscillator would be for those hams who would volunteer as examiners and would administer Novice exams and sometimes Conditional License exams. Obtaining a Novice License before 1980 required that the prospective ham to go out and find a licensed General Class or higher ham who would volunteer to give him the 5 wpm Code test. The first step was to for the volunteer examiner to obtain a 610 form from the FCC. Those forms used to have a section for the examiner to fill out confirming that he had given a 5 wpm Morse Code test to the applicant and that he had passed both sending and receiving. The requirement was to have at least one minute of solid copy and one minute of solid sending. Next, the volunteer examiner would send in the completed 610 form to the FCC. Six weeks later, the examiner would receive the applicant's Novice written test via the mail at which time he would contact the applicant to come over and take the test. The completed test was sent into the FCC again and hopefully, six weeks later, the applicant would receive his Novice license and call letters (again, via the mail.) This arduous and lengthy procedure started to change as the ARRL Volunteer Examiner program was started in the 1980s. As both the code test and the written theory test could be administered on the same date the time to acquire the license was reduced. Over time, the FCC has greatly improved their turnaround time on license processing also. Today, temporary license permits are issued upon successful completion of the exam, the new licensee will show up on the FCC website in a few days and the "hard copy" license can be printed from the FCC website..

Shown in the photo top right is the ICA Signa-Tone (ICA was the Insuline Corp. of America.) This is a very nice performing Code Practice Oscillator with a variety of tones and strong volume. The Bud Audio Oscillator is very similar in design to the Signa-Tone and dates from around the same time period - the late-forties to mid-fifties. Bud Industries is famous for their metal cabinets and metal relay racks. Bud Industries has been in business since 1928.


Signal Electric Manufacturing Company

Radio Telegraph
Practice Set (KOB)

With the evolution of wireless and its use of International Morse requiring the reproducer to work with tones indicating "dots and dashes" rather than "clicks and spaces" required for American Morse, some of the later KOB (Key On Board) units were also built with an electrically operated buzzer rather than the sounder. The buzzer allowed producing the "dots and dashes" of International Morse. Granted, they sounded a little "rough" but then so did the spark transmitters of early wireless days. The buzzer type KOBs were traditionally used for learning or practicing the code although it was possible to interconnect two or more sets for local wire communications. However, most were interconnected and used in "radio schools" and military radio schools for classroom International Morse send-receive education. KOB-type buzzer practice code sets were popular from the WWI era up to the 1950s. Later types sometimes are plastic and sometimes are toys rather than actual learning tools as the R-68 shown was. The metal tag between the key and buzzer shows International Morse Code. The R-68 shown is probably from the WWII-era.  


The Instructograph Company, Chicago, Illinois

The Instructograph

Using records to learn the code had one disadvantage. You were using a phonograph and probably couldn't use earphones, so everyone around got annoyed as they had to listen to you as you were learning the code. The Instructograph eliminated that problem. Most were designed to run into earphones. It could also operate an external oscillator for multiple student use. The Instructograph uses punched paper tapes to send code. The paper tape actuates a set of contacts when holes are present and break contact when there are no holes. The length of the hole determines whether a dot of a dash is sent. The paper tape is pulled through a "smooth button" on the actuator arm that moves the arm as the button drops into the punched holes. The actuator arm also has the contact that makes and breaks the circuit that drives the oscillator or other external sounding device. Early machines used a wind-up phonograph type motor while later versions used an AC operated electric motor. Early versions sometimes had a battery operated oscillator inside using a single type 30 tube. Some versions relied on an external oscillator. Later versions had built-in solid state oscillators. The paper tapes were available for either American Morse (landline or railroad code) or International Morse (radio) code (Instructograph always referred to International Morse by the name Continental Morse.) The tapes were kept in individual boxes or metal tins. Usually a larger box was provided for tape storage and instructions. The paper tapes progressed from learning the alphabet and numbers on up to full messages for building your speed. And, of course, the speed of the machine was adjustable so you had complete control of how fast you wanted to have the code sent to you. Since the paper tapes opened and closed contacts any variety of external signal indicators could be used for learning that particular type of code - from lamps for visual indicators to sounders and batteries for American Morse (in addition to the audio oscillator for International Morse.)

Shown in the photo to the right is a fairly early Instructograph that uses a wind-up motor to drive the tape pickup spool. Note that one this early version, the tape spools are made of wood. Also, the tape containers are metal tins with "Continental" printed on the lid. Each tin is numbered for identification. Note also that this machine has a small pointer knob at the upper left of the panel. This is the power switch and volume control for the battery-operated audio oscillator that is mounted inside the cabinet. The oscillator uses a single type 30 vacuum tube. This excellent condition Instructograph is complete with all of the tapes, extra spools and a spare type 30 tube. It belonged to W3ON.

Instructographs and the FCC at San Francisco - Instructographs used to be everywhere. A lot of hams had them. Even the FCC used them to give the code tests to hams. The 13 wpm code test I took from the FCC in San Francisco in 1970 was sent with an Instructograph machine. When administering the code test, the FCC engineers would deliberately try to increase your nervous apprehension and level of discomfort to see if you really "knew" the code and could copy under difficult conditions. Typically unfriendly, the SF-FCC engineers communicated to ham-test, license upgrade-applicants with terse verbal commands along with various facial expressions that were supposed to highlight the dubious likelihood of any applicants passing the CW test. If you did pass the SF-FCC CW test, you could copy CW in the worst environments.

In contrast, in the late-eighties I took (and passed) the 20 wpm code test for Extra Class. The CW test was sent using a cassette tape machine by a VE (volunteer examiner) who did everything he could to increase the comfort level and reduce any test nervousness. "Do you need a pencil? Is the volume okay? Would you like a cup of coffee?," were some of the questions designed to reduce "test nervousness." Quite a difference from the brusque manner of the FCC engineers. At that time, the VE-CW test included submitting my "hard copy" along with a ten question, "fill-in-the-blank" written test. Around 2000, the CW qualifications for Extra Class were reduced to only the beginners level of 5 wpm. Eventually, CW requirements were totally eliminated for Extra Class and all other levels of amateur licensing. How times have changed.


photo left: This is a late Instructograph that runs on AC and has an internal solid-state audio oscillator. Note the larger box provided for tape storage and instructions.


Brief History of the Telegraphic Codes

American Morse was the original telegraphic code developed in the 1840s. Initially, it is a code that was to be printed on a Morse Register. Since it was not aurally received, the code is more difficult than expected and is made up of dots, dashes, longer dashers, even longer dashers and different length spaces used between some of the dots or dashes to create certain letters. Once operators learned they were aurally receiving sent messages in "real time" by listening to the Morse Register operate, the mechanical printing interface was replaced with a simple "sounder." However, the Morse code remained the same, since that was what the operators were "reading." No doubt, the original Morse was a difficult code to learn and it was difficult to send and receive without errors.

By the 1850s, sending Morse over long runs of underwater telegraph cables was proving difficult due to corruption of the dots due to a factor called dispersion. The distortion or corruption worsened the faster one attempted to send a message. Accurate message reception required that the code be sent much slower than normal, sometimes as slow as only one word per minute. In order to make the original Morse code better suited to being sent over long runs of underwater cables required changing many of the letter and number characters in an effort to remove all of the variable spacing and different length dashes. This ultimately "slowed" the code down and allowed more accurate reception. This revised Morse code was developed by Ferdinan Gerke and initially it was called Continental Code. It was adapted by the German telegraphic cable companies in the 1860s. Continental Code was continually tweaked and improved to allow better and better sending and receiving ability. At this time (1870s,) the original Morse code was referred to as "American Morse" since it was mostly used just in the USA. Continental Code was used in Europe and the rest of the world. By the 1880s, Continental was being called International Morse and, by this time, it was basically the same International Morse we use today.

As wireless communications started, many of the US operators used American Morse. Some types of wireless detectors only worked relays and sounders, like coherer detectors. As wireless improved, it was obvious that International Morse was more suited for spark transmitters and for reception on mineral detector receivers. In 1912, the Wireless Conference in London ruled that all ship wireless messages were to be sent by International Morse. Most other wireless users also followed this rule. Hams still tended to use whatever they were accustomed to. Many hams at that time were also railroad telegraphers and American Morse was sometimes found on the hams bands. There was an attempt to make International Morse the standard for landline users but resistance from companies like Western Union and other wire companies, who knew that sending messages via American Morse was about 20% faster than International Morse (and also the wire companies didn't want to have to retrain their operators,) prevented International from being adapted for USA landlines. Eventually, as communications moved away from landline wire messages, American Morse wasn't used after the mid-twentieth century. International Morse has continued on being used in radio communications both for the military and the amateur.

Here's an example of the difficulty of learning and using American Morse. The letter T is a dash. The letter L is a long dash. The number 0 is an even longer dash. The letter P is five dots. The number 6 is six dots. The letter C is a dot followed by a short space and then two dots. The number 5 is three dashes. The letter O is one dot, a long space and one more dot. The spaces can be three different lengths depending on the character or word or sentence. To become proficient in American Morse took a lot of time and a lot of practice. Receiving it is even more difficult. You can send International Morse and receive it fairly easily on a sounder. Very late in the railroad's use of telegraphic communications, some railroads did use International Morse but the majority stayed with "railroad code" until the end.  


Landline (Wire) Telegraph Equipment

The following is just a very small sample of the vast amount of Landline Telegraph Equipment that was produced. The earliest telegraph gear will be for wire landline use going back to as early as the middle of the nineteenth century. Most of what we find today dates from the early twentieth century. Landline used American Morse Code which was a significantly different code when compared to the later International Morse Code. Aurally the two codes are completely different with International operators hearing "dits and dahs" in sine wave tones while the American Morse operators hear "clicks and spaces between clicks" from a sounder. 

J.H. Bunnell Company, W.U. Tel. Co. & O.C. White Company

Sounder in Resonator Hood with Articulated "Straight-Arm" Desk Mount

The sounder is the "receiver" of the wire telegraph. Originally the "Morse Register" was a mechanical method of receiving the code but operators soon found that they could "read" the code directly from the aural information heard as the machine operated. This led to Morse's associate, Alfred Vail, building a device that allowed the operators to hear the code directly. The sounders were sometimes installed into resonator hoods to amplify the clicking sound produced. Sounders are rated by the DC resistance of the solenoids. The DC resistance determined the maximum distance between two stations where the sounders were connected directly to the line and were powered by the battery DC voltage source. The greater the distance between stations, the higher the DC resistance of the wire was and therefore the greater the voltage drop if the sounder solenoids were of a low DC resistance. Sounders were produced from the mid-nineteenth century up into the 1960s or so.

Otis C. White was located in Worcester, Massachusetts and specialized in cast iron, articulated arm mounting devices, mainly for lighting for desks and machines. The use of the articulated arm allowed the operator to position the sounder resonator hood for best listening depending on the noise and activity in the station area. Active use is probably later than the patent date that is on White's arm, which is 1911. The actual use date of this one shown is probably in the 1920s or 30s. Obvious are the U.S. Army Signal Corps acceptance stamps implying the military use of this example.

The sounder used was built by Bunnell and has both solenoids wired to individual terminals. This allowed the user to connect the solenoids in series or parallel depending on the line distance. Each solenoid measures 200 DC ohms so a series connection results in 400 ohms and a parallel connection results in 100 ohms (although the tag indicates "18-400 ohms.") A metal Western Union (W.U. TEL. CO.) tag is mounted to the sounder base implying that WU may have been supplying the Army with their telegraph system in this particular case. The resonator hood is also built by Bunnell and it has a cast metal rear bracket that was probably for paper "messages to be sent."


- W - U - TEL - CO -

Western Union Telegraph Co.

Bunnell 120 Ohm Sounder and Algoma Resonator Hood
with O.C. White Co. Articulated
"Curved-Arm" Mount


This is another version of Otis C. White's articulated arm mount for telegraph sounder and resonator hood. Note that with this version the main arm is curved downwards to reduce the total height of the assembly resulting in the hood being above the table top by less than 12 inches. Compare this "curved-arm" to the White articulated arm mount shown above which has the "straight-arm" version of the mount. With the "straight-arm" the total height of the assembly and hood is about 16 inches above the table. The "curved-arm" only has "patented" embossed along with "O.C.White-Worcester, Massachusetts" where the "straight-arm" has a 1911 patent date. This "curved-arm" version is probably the earlier of the two versions.

The Resonator Hood has "- W - U - TEL - CO -  RESONATOR HOOD  MFD. BY ALGOMA PANEL CO." on the tag.

The 120 ohm sounder was built by J. H. Bunnell & Co.

Probably dates from the early twentieth century.


Western Electric

3B Sounder in Resonator Hood with Brass Pedestal Desk Mount


Western Electric was the manufacturing arm of American Telephone and Telegraph Company. They made many types telegraph devices such as keys and sounders along with other telegraph equipment. Western Electric was the W.U. competition. Western Electric and Bell backed the telephone over the telegraph which seemed to favor W.U. at first. As the telegraph gave way to the telephone, W.U. lost substantially and they were eventually bought by the Bell System in the late twentieth century.

This is a Western Electric 3B 20 ohm Sounder mounted in an oak resonator hood mounted on an impressive brass pedestal.

DC Resistance versus actual distance has a few variables. The voltage source was determined by how many batteries were being used. The potential available would be an important factor in distance covered. Although it's not really specified what voltages were used, it probably was between 50vdc and 150vdc. The size of the wire determined the DC resistance per foot of the line between the two stations. The distance between field poles determined what type of wire and what diameter wire was used and that determined the DC resistance per foot. Sounders were normally energized and the entire line was normally a complete series circuit. Each key had a switch that was kept closed when all stations on the line were in the "receive" mode. To send, an operator would "open the key" and that would drop out the sounders at which time the operator would begin sending his message and that operated all sounders on the line. When finished, he would "close the key" to keep the circuit energized. All of the sounders on the line presented a "series load" that was the DC resistance of the all of the solenoids added up. Each line had to have the total load calculated to keep the system capable of operating while taking into account all of the other variables that might happen along the line. The higher the total resistive load on the line, the lower the voltage drop across the line and the longer the distances that can be covered by the system.  


J.H. Bunnell Company

4 ohm Sounder

It's likely that several million sounders were built over the years from the mid-1800s up to the mid-1900s. Every railroad station had to have several. Sometimes the local telegraph office was at the local post office. Other times there was a specific "telegraph office" in the town. Then there were the many other users that included inter-office communications (pre-telephone) in large buildings or building complexes. The local users had the 4 ohm sounders. These were just about the lowest DC resistance available and allowed for very short distances on direct wire operation using a couple of gravity batteries as the voltage source. It was also common to use the 4 ohm sounders in conjunction with "sensitive relays" that allowed the relay to operate greater distances on the line and then to operate the sounder as a local device. Some of the 4 ohm sounders were for instructional devices since this was about as "local" as one could get.

Patent date on this Bunnell sounder is May 7, 1895 but it probably dates from much later.


Signal Electric Manufacturing Company

20 ohm Sounder


Signal Electric Mfg. Co. started out in the 1890s as Menominee Electric Co. since they were located in Menominee, Michigan. The company built and sold telephone and telegraph equipment. The company also built some wireless items like loose couplers and other electrical parts. The name was changed to Signal Electric Manufacturing Company and they remained in business until the 1960s when they were purchased by a Thermos company.

This Signal Electric sounder is built a little different from the other sounders shown. Note that the individual pieces, the frame, the anvil and the solenoids are mounted directly to the wooden base rather than mounted to a metal plate that would then mount to the wooden base. The metal base mount provided a permanent alignment of the sounder components. Mounting the sounder components directly onto a wooden base could introduce misalignment if (over time) the wooden base warped or cracked. The 20 ohm DCR solenoids imply that the sounder was intended for relatively longer distances (or less load) when directly operated on the line.  



Western Electric

3C 140 ohm Sounders


Western Electric 3C 140 ohm Sounders would be for long distance operation direct on the line. Initially, Morse's system used two wires but very soon it was discovered that a single wire could be run between stations and each station could use an Earth ground for the return. Each station had batteries for the potential and large surface area metal plates were buried to provide a substantial Earth ground. With low DCR sounders drawing more current to operate the voltage drop across the single wire increased to the point where the sounder wouldn't operate. High resistance sounders didn't draw as much current and therefore could operate for greater distances before the voltage drop increased to the point where the sounder wouldn't function. The system depended on how many sounders were in series on the line. Fewer sounders would require each solenoid to have a higher DCR.  

Most stations would use the low DCR sounders on a local circuit within the station and the line(s) would be operating high DCR Telegraph Relays.


Landline Hand Keys

J.H. Bunnell 2A Legless Key for Western Union
Western Electric Leg Key for Western Union


Like sounders, millions of hand keys have been built by many different manufacturers since the wire telegraph service began. The "landline" hand key is slightly different from a "radio" key. The "landline" key must have a lever switch since that allowed the operator to "open the line" in order to send his message using the hand key. When the operator was finished he "closed the line" which meant that the switch lever was closed which then completed the line circuit and returned the station and the line back to "receive." Many wire telegraph keys were later stripped of their lever switches by ham radio operators since the switch wasn't necessary for radio operation. Wire telegraph keys also had very small contacts, usually .060" diameter was the normal size. Some keys were fitted with long connection rods that protruded though the table top and allowed for wires to be routed under the table. These types were called "Leg Keys." Most keys were "legless" and mounted directly on the operator's desk and were wired as needed. Two examples are shown, the Bunnell 2A Legless Key was made for Western Union and is marked as such. The second key is a Western Electric Leg Key built for Western Union. Both keys date from around 1900.


J.H. Bunnell Co.

Key on Board (KOB) Learner's Set


These wooden board key and sounder sets (called KOB, Key On Board, though they probably should have been called KASOB, Key And Sounder On Board) were popular mainly as a learning tool. Very early uses sometimes had interconnected KOBs as methods of local communication within large buildings or other similar applications (even large houses.) Rarely, a KOB might have been used on the line in a station but normally the station setups had the key mounted to the table and the sounder located in a resonator box with these two devices working into telegraph relays for long distance communication over the wires.

Shown is an early Bunnell KOB from the early 1880s. It features a "camel back" key with the steel lever painted gold. The key's base is also gold finish. The sounder has the earlier style of a cast iron coil and sounder arm frame and a separately mounted brass anvil. The KOBs made in the nineteenth century tend to have very decorative pin striping and scrolling typical of the era they are from. A patent date is stamped into the wooden base of May 1, 1877. Also, the wooden base was modified by removing the front one inch of material to allow mounting it directly to something or for some custom installation.


J.H. Bunnell Co.

Key on Board (KOB) Learner's Set

This Bunnell KOB is a somewhat later than the set shown above. It probably dates from the late-1880s. Its key has the "camel back" lever design but this lever is made out of brass. Normally, the sounder's solenoid coils were covered with an embossed type of paper that was usually black in color. The paper covers are gone showing just the cotton covered magnet wire used in winding the solenoids. Note that the key knob and the switch knob are brown in color. At the time, condensite or hard rubber was used for these pieces. Hard rubber tends to turn brownish-green with long exposure to light. Again, as typical for the era, decorative pin stripping is applied to the black japan finished key base and the sounder arm/solenoid coil frame of the sounder.


Unknown Manufacturer

Key on Board (KOB) Learner's Set

There are no markings to indicate who manufactured this KOB set. The thumb screw knurls look like Bunnell's style but that's not a positive indicator since the connection terminals are very different from those used by Bunnell. This KOB set probably dates from the 1890s. It has a later style key mounted on the board. Note that this key has the stamped steel, single-piece, nickel-plated lever with the gentle downward curve for proper placement of the knob. This style of lever was developed by Bunnell in the 1880s with the purpose of simplifying construction and eliminating the problem of loosening of the pressed-fit lever pin. The sounder is still comprised of separate pieces mounted directly to the board indicating that the KOB is not so late that it would have a base-mounted sounder. This sounder's solenoids are 4 ohm indicating that it's intended for local operation, as would be typical of a learner's set. The "4 OHMS" is stamped on the board.


Unknown Manufacturer

Telegraph Relay


When great distances had to be covered, sounders generally weren't operated directly on the line. A sensitive relay used high DC resistance solenoids to operate a set of contacts that could operate a local circuit which had low DC resistance sounders. The DC resistance on this relay is 50 ohms which allowed it to operate greater distances between stations. There is an extra switch circuit to the right for opening or closing the wire circuit. The switch contacts go directly to the two terminals on the right end of the relay. Lifting the red knob opens the switch for sending. The middle terminals are for the local line connection and the left end terminals are for the wire line input was normally wired to include the switch circuit to keep the line closed for receiving messages.

The manufacturer of this beautiful device is unknown. There isn't any builder identification anywhere. This relay probably dates from the early twentieth century.


Unknown Manufacturer

Polar Relay


The builder of this beautiful Polar Relay isn't identified. The two solenoids work in conjunction with the "wrap-around" horseshoe magnet. The contact arm remains stationary between the N and S contacts if the solenoids aren't energized. If a connection is made to the two input contacts that is positive then the arm will move to the N contact. If the opposite polarity is made to the input contacts (negative) then the arm will move to the S contact. The connection labels are arbitrary and dependent on the hook up and system. The basic function is that the change in polarity between the two input contacts results in the selection of either arm to N or arm to S with those terminals being the three grouped together on the left side of the board. The input terminals are the two grouped on the right side of the board. The polar relay worked with a different type of telegraph system called the duplex circuit that could run multiple signals on a single wire. This evolved into the quadruplex system the used polarity changes for additional signals on a single wire. This polar relay is beautifully made with turned finished brass sub-base and a mahogany wooden base. It probably dates from around 1900, perhaps a little earlier (it came from Virginia City, NV.)


The Instructograph Company, Chicago, Illinois

American Morse Instructograph


This is an early Instructograph with wind-up motor drive. Note that this version has a removable lid that is held on with two latches. Note also that the tapes are for American Morse. I'm not sure about the masonite panel. It appears to have wear and looks original but I've never seen masonite used as a panel on any other Instructograph. Note that this version doesn't have a knob anywhere on the panel. This indicates that the machine has no internal, battery operated audio oscillator. This implies that the machine relies on the user to provide an external indicating device. Since the tapes are for American Morse the reproducer should be a sounder and battery combination.



U.S. Army Signal Corps

Contractor: The Allen D. Cardwell Mfg. Corp.

Model: TG-5-A Telegraph Set


Telegraph Sets were used for various types of communication where wires had been placed between the points that were sending and receiving. The distance covered depended on the voltage used, condition of the wires and, if an earth return was used, then the ground conductivity was important. Internally, a three volt DC battery source can be used. Also, the three volts can be connected externally, if necessary. If the bell is to operate then 22vdc is necessary and that has to be connected externally. The buzzer operates on three volts but, depending on the condition of the wires and the distance, it was sometimes necessary to adjust the "Spring" and the "Gap" of the buzzer for best results. The single earphone was for listening to the buzzer. The bell would operate if the earphone wasn't inserted into the jack.

Once everything was connected, the sender would depress the key several times. This would ring the bell at the other end of the line. The receiving operator would insert his earphone and could then hear the buzzer operating as the sender depressed the key. The line is closed when the key is up so when the sender stopped then the receiving operator could send. Wires were connected to L1 and L2. A single wire could be used "L1 to L1" with L2 grounded at both stations. Multiple stations could also be set up in both series connections or with common earth returns.

These Telegraph Sets were intended to be temporary communications or somewhat portable considering that the wires did have to be run first. However, the original package also included a canvas carrying bag for the TG-5-A. The implication is that using the TG-5-A assured the communications were somewhat secure since the operators had to be Morse proficient. And, since the reproducer is a buzzer, International Morse is implied.

Contract date on this TG-5-A is 1941.




1. "The Vibroplex Co.,Inc." by William R. Holly K1BH - 1990 -  Detailed history of Horace Martin, James E. Albright and the Vibroplex Company. Photo of Horace Martin from this book.

2. "Vibroplex Keys" - Tom French -  Detailed info on the various models


1. Vibroplex Serial Numbers - WW7P (John Elwood) Serial Number Log is at  the serial number log is a PDF. The Vibroplex Collector Net is maintained by Randy Cole KN6W and contains more information on Vibroplex than just serial number dating. Identification, details on tags, history and more. Click on "DATE" for WW7P Serial Number Log.

2. Telegraph-Office - Landline and Radio Keys plus more - - K5RW Neal McEwen's extensive website devoted to telegraphic codes and instruments. Great reference source.

3. W1TP Telegraph Keys -  -  W1TP, Ted Perera's vast website has all types of keys and gear with lots of photos. Includes keys from other collections. Great reference source.

4. Speed-X - Most of the information on Speed-X came from K5RW, W1TP and especially from N7CFO (Lynn Burlingame) and WW7P (John Elwood.) The N7CFO and WW7P information was consolidated into an article that appeared in the British magazine "Morsum Magnificat - The Morse Magazine" in February 1996. The photo of Les Logan is from that article. It's available online at:

5. T. R. McElroy - World's Champion Telegrapher -  has the best information on Ted McElroy. Wikipedia also has some interesting info. Photo of Ted McElroy from a Candler Ad that happened to be in the 1947 ARRL Handbook but Candler used this same photo in his ads for many years.

6. Dow-Key - Paul Dow history and information from the N7CFO website.     

7. British and European Keys plus many others -    Mark Brundrit M6BRN has an extensive telegraph key website with lots of different types of keys from many different countries. Excellent photography. Great reference source.

Telegraph Key Parts 

1. I've purchased as few parts from "azroadrunners" on eBay. This is a good source of some types of vintage parts and some reproduction parts. I've purchased paddles and they are good quality reproductions.

2. Many new replacement parts for various models of Vibroplex bugs are available from the company. Go to: and click on "Repair and Parts."


Thanks to all of those hams and key collectors that have contributed information and details on all types of telegraph equipment over the years, either in-person or "on the air."


Henry Rogers, Western Historic Radio Museum, Radio Boulevard 2013 - 2019,   added "References" Jun 2017, Re-organized into 2 parts Feb 2019, Speed-X info enlarged Jul 2019,

Telegraph Keys Part One                         Return to Home Index           



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