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In robust rectangular, black canvas covered wooden box with handle and removable hinged lid. After opening the lid we see an ebonite panel with two rotary switches, two double knife switches, two tuning knobs, a clutch control, a potentiometer control, a small knife switch, a push button for a buzzer, a Perikon detector with crystal, a carborundum detector, eight copper terminals and four wires (two white and two black) equipped with terminals. There are two lockable compartments, one in the lid and one next to the front plate. A battery can be placed there that provides pre-tension on the crystals and power for the buzzer. Above that compartment there is a place to store the headphones.
Private (later Lieutenant) Harry Wilgress Miller, No 2 Wireless Section, Australian Flying Corps, in the Radio Room with a Mark III* Short Wave Tuner. He was trained in Australia before his departure to Europe. (photo: Australian War Memorial 1917-1918)
The compartment in the lid contains twelve spare mounted mineral crystals for use in the Perikon detector. There is a nickel-plated circular holder in the lid for a pocket watch and wooden brackets for holding maps.
By the middle of the First World War, the vacuum valve was being successfully developed as a detector and an amplifier, but its growing use by the Military did not immediately cause the crystal to become obsolete. In fact, one of the most well known and widely used wireless receivers was the Mark III* Short Wave Tuner.
6595 Tuners were made for an average price (the price differed slightly per manufacturer) of 30. During the war, the British used the Mark III* in the trenches. In his book "Radio! Radio!, Jonathan Hill writes that these early crystal sets "were used by Royal Air Force Corps ground stations for the reception of Morse Code signals transmitted from aeroplanes flying over the battlefields of the Western Front. The pilots job was to direct the gunfire of artillery batteries on the ground via an RFC wireless operator attached to each battery. With a clear picture of the battlefield on the ground, the pilots would transmit in Morse the coded position of the enemy using their Sterling No. 1 spark transmitter (1915) and the message would be relayed on to the gunners who would then take the appropriate action. (Jonathan Hill, Radio! Radio!, page 26). This may seem primitive according to today's standards, but it was a technological revolution in its time. It enabled artillery soldiers to shoot much more accurately than possible before, without knowing the position of the enemy and the results of their shelling.

The Sterling No.1 Spark Transmitter
Australian Marconists listen to a Marconi Mark III* Short Wave Tuner at a training in Australia (photo: Australian War Memorial, 1916)
Marconi's Wireless Telegraph Company developed the Mark III* Tuner in 1915. From 1916, the device was also manufactured by a number of other companies, including Robert W. Paul, the W/T Factory, A.T.M. Company and Johnson and Phillips. This London-based company made the Mark III that is part of my collection.
High-quality parts were used in the manufacture of the set. The finish was also of very good quality. The housings of most Mark III* tuners were covered with black painted canvas, but sets were also made with a mahogany case. In addition, Mark III* Short Wave Tuners were made with folding aluminum legs (see photo above), presumably to keep the radio off the ground and out of the mud.
The Mark III* Short Wave Tuner is a crystal receiver that uses both carborundum and Perikon detectors. The wave range is 100-700 meters.
A bright emitter can also be used instead of the crystal detectors; a switch on the right side of the set can be used to select the carborundum detector, the Perikon detector or a radio lamp.
The Mark III* is tuned using a buzzer. First the detector switch is set on the Perikon detector. The inductor and the variable condenser are set to the estimated wavelength for receiving a particular station. The switch for the buzzer is then pressed; this produces oscillations that work as if a station is transmitting at the estimated frequency. Finally, the different tuning knobs are adjusted until the loudest sound in the headphones is heard; the detectors are then set in the same way until the most powerful sound is heard, after which the buzzer can be switched off. The Mark III* Short Wave Tuner is then ready to receive.
After the war, many Mark III* Tuners appeared on the surplus market and were bought by radio amateurs.
Data  
Serial number: 5212
Dimensions (hwd): 20 35 31 cm
Made in: 1917
Purchased in: 2018
Voltage: 2 x 6 volts
Weight: 7,3  kg
   
   

Circuit
Article in The Wireless Word, January and February 1920

What was broadcast in 1916?

 

Listen to an "Aircheck", recorded on wax cylinder, of an American morse-transmitter from that period

 
The receiver inside

The Johnson & Phillips Mark III* Tuner with lid opened

This page was last edited on 08.06.2019