Western Historic

 RADIO MUSEUM

Wireless Era Ham Gear
and
Commercial Wireless Equipment

1910 - 1927

 Photo: Wireless Operator onboard the S.S. Columbia (photographed by M.H.Dodd  -  ca.1913)

M.H.Dodd  -  1910 Wireless Station Parts

These parts are all that remain of M.H.Dodd's 1910 Wireless Spark-Gap Station. The Tuning Inductance and Detector Stand are homebrew. The Spark Coil is from Electro Importing Co. while the single earphone is from the Kellogg Company. Most of the other 1910 parts were used to construct Dodd's 1912 station. The vintage photo shows Dodd at the controls of his 1910 station.

M.H.Dodd's

1912 Wireless Station

This is the Wireless Station that M.H.Dodd built in 1912. It is virtually complete, authentically reassembled and is displayed with photographs, taken in 1912, showing Dodd using his station. Dodd's station survived intact because new regulations that went into affect in August 1912 made both Dodd and his station illegal. Rather than rebuild the equipment (for 200 meter operation) and get the new license required, Dodd disassembled the station in 1913 and packed it away in a large trunk. The station remained in that trunk for the next 86 years until we discovered it in Dodd's backyard shed. For the complete story on this amazing find, with lots of photos, go to the navigation link below and click on "M.H. Dodd's 1912 Wireless Station."

Photo of M.H.Dodd at his 1912 station.

J.H. Bunnell Co.

Mascot Spark Gap

An early spark gap from Bunnell advertised in Modern Electrics and Mechanics in 1914. It is mounted on a ceramic base and the tips are made of zinc. Zinc was supposed to produce a very clear "spark tone." Selling price in 1914 was $1.00 The one knob on the left is not original.

Spherical Audion Receiver - 1915

The builder of this wonderful Spherical Audion Receiver is unknown. The circuit uses a loose coupler tuner and a non-regenerative, grid-leak detector. On the lower right side of the panel is a dual control the outer knob of which varies the coupling via a bell crank while the inner knob selects the secondary turns. The back-up crystal detector was added at a later date. This was a common addition as it allowed the receiver to still be used if batteries were depleted or the audion failed. The cabinet is mahogany and the panel is .75" thick hard rubber. Signals picked up on this receiver are either weak or inaudible! Regeneration would have been a big help but even the commercial regen sets were at least a year away, (1916 Paragon RA-6.) This working receiver was tested using several different kinds of detector tubes by way of a homemade adaptor. The best performance was using a Moorhead ER type tube, though these are vintage 1919 tubes. The sensitivity was a bit better than a modern germanium diode.

"Arlington" - Loose Coupler

These "Receiving Transformers" were generally called "loose couplers" and were used as the receiver's tuned circuit in many early stations. The larger LCs were sometimes called "Arlington" types as they could tune to the very long wavelengths for time signal reception. Arlington-type LCs will have a greater number of turns on the primary and secondary with larger coil dimensions. The LC shown is probably a Signal R-22 from about 1914.

Wm. J. Murdock Co.

No. 334 Loose Coupler

This loose coupler was designed primarily for amateur use. Fewer turns and smaller dimensions result in better efficiency at medium wavelengths. Dates from 1914, or later. The Alexander Bill created new regulations in August 1912 that moved amateur operation to 200 meters (or below) which resulted in the beginning of experimentation into the shorter wavelengths. Original selling price was about $15.00

Peerless Wireless Company

"High Grade Radio Apparatus"

Model B

Peerless Wireless Company was located in Detroit, Michigan and offered this assembled "Model B" receiver using a loose coupler tuner with crystal detector as their "High Grade Radio Apparatus." The original detector was replaced with a later, after-market Galena detector that was probably of better quality (and more sensitive) than the original. Two sets of earphones can be used with this set - the two sets of "TEL" terminals are connected in parallel. The large contact switch tunes the primary coil by selecting the number of turns. The secondary turns are selected by the contact switch on the front of the secondary coil form. The small switch allows the antenna to be removed from the primary coil - an early form of  "send -receive" switch. A fixed condenser is located under the board. Dates from around 1914 to 1917.

Chelsea Radio Co.

Wm. J. Murdock Co.

These are variable condensers used in tuning amateur wireless receivers. The condensers allowed for a fine adjustment of the LC circuits. The Murdock is from about 1915 and the Chelsea is from about 1920.

Navy Type SE-1420B

This is the "destroyer" receiver designed by Louis Hazeltine in 1918. The Navy contracts were built by either AMRAD or Wireless Specialty Apparatus. The circuit uses a single vacuum tube (either a VT-1 or Moorhead ER) as a three-circuit regenerative detector. Wavelengths covered were from 300 meters to about 7500 meters. The Triode Type B, Two-Stage Audio Amplifier was also normally used with the SE-1420. The cabinet is lined with copper sheet with an additional copper shield to provide isolation between the primary tuned circuit and the secondary tuned circuit resulting in great selectivity and immunity to interference. This SE-1420B is from a 1919 or 1920 contract built by WSA. This receiver is still in unrestored condition even though I have had it since the 1980s. I still have to replicate the elaborate tube socket as the original is missing.

Thordarson

1/2 KW Wireless Transformer, Type R

These high voltage transformers were the "heart" of many amateur spark stations providing the necessary potential to charge sending condensers and create the damped waves which were the main component of spark signals. The primary of the transformer is keyed via the AC line with perhaps a primary choke also in the circuit for extra protection. The secondary is connected (usually through kickback preventers) to the closed circuit (usually an oscillation transformer primary, charging condenser and rotary spark gap.) The closed circuit is coupled to the antenna via the oscillation transformer secondary. On a 1/2KW transformer the secondary voltage is about 12KV. The levers control a sliding section of the core that can be moved in or out, creating an adjustable "magnetic leakage gap" which served to limit the high primary current that flowed during the discharge at the spark gap (this discharge was a momentary short on the secondary) and also to help prevent transmission at two frequencies (called double wave emission.) The Type R sold for $21 in 1917, just before the WWI Navy ban on receiving and transmitting. This ban was not lifted until April 1919 for receiving and October 1919 for transmitting.

Klitzen Radio Mfg.

Rotary Spark Gap No.125

Micaoil 1KW Condenser

This Klitzen No.125 Rotary Gap is from 1920 and originally sold for $22. The Klitzen Micaoil Sending Condenser is .01uf at 30KV rated at 1KW and is also from around 1920. The condenser uses mica as a dielectric and oil for insulation along with cooling. These components would have been used (along with an oscillation transformer) in a transformer-energized spark transmitter to provide the spark gap and the capacitance necessary for damped wave signal generation.  Using a rotary gap in the secondary circuit gave the advantage of apparent modulation. This was accomplished by allowing the gap discharge to occur at various random levels of the charging AC voltage (non-synchronous rotary gap.) The varying discharge voltage (and resultant different amplitude peak of the damped waves in each wave train) was heard as an audible tone allowing better copy.

Wireless Improvement Company

2KW Auxilary Hand Key-Type SE68A

Made for U.S. Shipping Board in 1920, these large keys used .625" diameter silver contacts to handle the high currents of spark transmitters. The brass ring around the lower contact is a "cooling ring." The base is made of hard rubber. These keys were later sold as surplus to hams and are advertised in the back section of the 1937 ARRL Handbook (for $7.50.)

Standard Assembling Company

The Standard Assembling Company offered this regenerative tuner utilizing a Deforest tuner and Duo-lateral Coils for $50 in 1921. Using a DeForest type tuner can be very annoying because the location of the adjusting knobs requires the operator to reach over the coils. The hand capacity involved in making adjustments de-tunes the receiver resulting in temporary settings that change soon as the hand is removed. Most operators would use a pencil to push the coils into the proper adjustment instead.

Adams-Morgan "Paragon" RA-10/DA-2 Receiver

The Paragon was designed by the quintessential ham and engineer, Paul Godley. A favorite of the "Spark Hounds," the Paragon RA-10 tuner was first offered in 1920. Later, in 1922, the DA-2 detector and two-stage audio amplifier became available. Paul Godley had designed the RA-6 - the first commercially built shortwave regenerative receiver - prior to WWI. After the war, Adams-Morgan and Chicago Radio Labs still offered the RA-6 for awhile. Godley redesigned the tuner using a variable condenser in the secondary circuit and a variometer in the plate circuit and this became the RA-10. The new Paragon was Godley's choice as one of the receivers taken to Ardrossen, Scotland for the Amateur Transatlantic Tests, in December 1921. Though most of the stations were actually received on Godley's homebrew superhet, an RA-10 and a proto-type DA-2 were set-up on the receiving table in Godley's tent at Ardrossen. Adams-Morgan took full advantage of the advertising potential of the Tests claiming the Paragon had received all of the ham stations. It didn't matter since the RA-10/DA-2 were very good performers and probably could have received much of what was claimed. Upon his return to the USA, Godley made an off-hand comment about the 50 watt vacuum tube oscillators out-performing the 1KW spark stations that probably put the death-knell to spark, at least as far as the hams were concerned.

A.H.Grebe  CR-5

The Grebe CR-5 is a single-circuit tuner with a regenerative detector that uses a UV-200 soft detector tube. The amateur that bought the CR-5 could up-grade his receiver, (when he could afford to), by purchasing the two-stage audio amp, RORK, and later add an RF amplifier or other accessories that Grebe offered. The CR-5 sold for $80 in 1921.

3ON  Amateur Station Parts

In 1923, John Ridgway was licensed as 3ON. He was only 12 at the time but he was able to construct quite a nice loose coupler using the oak boards from a discarded bed frame. The spark coil is a 1" Commercial and the sending condenser is homebrew using glass and foil. Spark was certainly on the way out by 1923 but John was able to make a few contacts and hone his ham skills. John became SK in January 2006 at the age of 92.

Colin B. Kennedy Co. - Type 281 - Shortwave Receiver

Colin B. Kennedy was a builder of high quality commercial receivers and home radios. If you were an affluent amateur, you might want to buy a Type 281 shortwave receiver with its matching Type 521 Two-Stage Audio Amplifier for your station. Using a standard Armstrong three circuit regenerative tuner, the 281 tunes from about 600 meters to about 150 meters. Most amateur operation in the early twenties was on 200 meters. A solid mahogany cabinet and polished Formica panel are indicative of the quality and care that went into the building of Kennedy receivers. Introduced in 1921 and sold for $145. See Kennedy 110 below for an unusual use for the 281 receiver.

Kennedy - Type 220 - Intermediate Wave Receiver

The Kennedy Type 220 Intermediate Wave Receiver and matching Type 525 Two-Stage Audio Amplifier made a very nice combination for either the professional radio operator or a well-to-do amateur. Covers 3000 meters to about 150 meters using the standard Armstrong three-circuit regenerative detector. Top quality was apparent with the silver plated dials on Formica panels that were machine engraved, all housed in a solid walnut cabinet. The 220/525 combination was introduced in 1921 and sold for over $200.

Wireless Specialty Apparatus

IP-501A

The IP-501A shipboard receiver was developed from the Navy SE-1420 series of wireless receivers. A three-circuit regenerative detector is combined with a two-stage audio amplifier along with all the extra features that would be required for reliable communications at sea. Wavelength coverage is from 300 meters to 7500 meters (40kc up to 1000kc.) The oak cabinet is lined with copper sheet and and extra copper shield isolates the primary from the secondary inductance for top-notch selectivity. Construction is heavy-duty, quality is first-rate and performance is excellent. All screw and nut joints are soldered after tightening at assembly. This was to prevent anything from coming loose inside the receiver with the constant vibration encountered onboard ships at sea. Most of the IP-501A receivers were sold by Radio Marine Corporation of America (a division of RCA) since Wireless Specialty Apparatus was cross-licensed with the RCA/GE/Westinghouse Group. The IP-501A shown is the early version with Telephone Condenser switch and nickel plated binding posts. Later versions eliminate the TC switch and the binding posts use bakelite caps. The IP-501A receivers were in use onboard ships throughout the twenties. They were even pictured in RMCA advertising into the thirties. Most were removed from ships by the mid-thirties. This particular receiver was originally used aboard the Matson Line steamship S.S. Mariposa. I have owned this IP-501A for almost 30 years. A ham friend traded a telephone pole for it and then sold it to me. I have performed three restorations on the set over the years, each one more complete and more original than the former one. The final restoration in 1984 resulted in the receiver looking totally original inside and, of course, fully functional. It is a very sensitive receiver and the calibrated wavelength dial is quite accurate - at least as accurate as you can be using wavelength, that is.

Kennedy - Type 110 - Universal Receiver

The ultimate in quality and performance. The Kennedy Universal was so well-respected that it was still being sold in 1925 when most regenerative receivers were considered obsolete, (ad in April 1925 QST.) Covers 25,000 meters to 150 meters (12kc up to 2.0mc,) which was just about everything you would listen to back in 1921, when it was introduced. Priced at over $300, it was certainly for the professionals, though a few wealthy hams also owned a Universal. The 110 shown is SN 951 and the 525 is SN 644, both very early three digit numbers in the typical Kennedy-San Francisco style with nickel plated binding posts and the Plate Potentiometer adjustment. Performance on this functional example is first-rate and, in the 1980s, I won first place (regenerative receivers) in Radio Age's "Radio Receiving Contest" with this Kennedy 110/525 combination.

Recreating Dr. Royal Rife's Multiple Frequency Generator   In the 1920s, Dr. Royal R. Rife began experimenting with the possibility that disease causing micro-organisms could be destroyed by exposing them to specific RF frequencies driving a multistage amplifier to power a high voltage-gas filled ray tube. Most of the early work was carried out using Kennedy receiving equipment as the RF frequency generators. This was accomplished by setting up the regenerative receiver in an oscillating condition and then coupling the desired output from the Antenna Input post. Frequency was controlled by the Secondary Condenser control and amplitude could be adjusted by either the Regeneration control or the Coupling control. Later, Dr. Rife was interested in the effects of modulated waveforms and used one receiver operating as an oscillator to modulate a second receiver also operating as an oscillator. Whether using single waveform or a modulated waveform, Dr. Rife would then route the signal into a five stage amplifier to boost the output enough to drive a high voltage, helium gas-filled ray tube. The effects of the RF exposure on various micro-organisms from this setup were monitored in Dr. Rife's elaborate optical UV microscope (center on the bench.)   photo left: A vintage photo of Dr. Rife's laboratory showing the Kennedy equipment (left,) his microscope (center.)

Our experiment was requested by two well-known researchers on Dr. Rife's early work, Jeff Garff and Jason Ringas (Rife Research Institute.) The goal of the experiment was to show that such a setup as shown in vintage photos of Rife's laboratory would indeed produce the desired waveforms. We used our SF Kennedy 110 Universal receiver with its SF Kennedy 525 amplifier and our SL Kennedy 281 Shortwave receiver as the generators. We powered the receivers using various power supplies to provide the 6 vdc at 3 amps required for the 110/525 combination and the 6 vdc at 1 amp required for the 281. Separate B+ supplies provided +20 vdc for the detectors in each receiver and the +60 vdc required for the plates in the amplifier. Each receiver and the amplifier were set up using the pure tungsten filament tubes of the time, UV-200 soft detectors and UV-201 hard amplifiers. Rife listened to the receiver output with earphones - probably to verify that each receiver was oscillating and to monitor any unexpected changes in his adjustments. We did the same. We measured frequency, amplitude and harmonic content with modern equipment, e.g. spectrum analyzer, oscilloscope, digital frequency counters, etc. Stability of the setup and the waveform output was surprisingly good. The repeat ability and accuracy were excellent, output was very high and the sine waves generated were free from distortion and harmonic content. Our conclusion was though it seemed unlikely that the Kennedy set up would be accurate or stable, just the opposite was true - it was fairly easy to duplicate the frequency generation part of Rife's experiments using early Kennedy equipment and the results were surprisingly good. Henry Rogers - June 11, 2007     photo left: The Kennedy 281 (top) and Kennedy 110/525 (bottom) set up with Lambda power supplies for the filaments and a homebrew eliminator for B+ requirements. The GR freq. counter is monitoring the 250kc signal from the Kennedy 110.

Owners/Operators:

Sharon Rogers KK7EI