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The single earphone headset is from the Kellogg Company and Dodd has this headset on in the 1909 photo.
Also visible in the 1909 photo is a bias adjusting resistance, probably for an Electrolytic detector, a detector switch, an air inductor, a telephone microphone and another earphone. The transmitter uses two spark coils, a homemade condenser made from glass photo plates and a homemade helix.
One also has to remember that the Secondary Coil has a certain amount of inherent or distributed capacitance.
Additionally, the capacitance and inductance also varies somewhat with the coupling position, so technically the Loose Coupler can be operated without additional variable condensers and, with a suitable detector and a set of 'phones, the Loose Couple will tune in signals.
The photograph used in the magazine is the same photo shown above except that the photo above is a scan of the original print and is not a copy of the magazine printed photo. Dodd wound his inductance on a form that was made from a 3" diameter 24" long piece of Bamboo - something you don't run into very often.
Dodd's station won First Prize and is featured in the June 1909 issue of Modern Electrics. The Tuning Inductance and Detector Stand are homebrew.
The smaller coil is the Secondary Inductance and this coil is tapped at various numbers of turns that are brought out to the contact point switch.
The base is poplar wood stained reddish-brown to look like mahogany. Dodd - ca.1913) Note that all of the equipment and the op's suit are in perfect focus - just his head isn't.There is a link provided to the 1909 ME Wireless Contest article (from Google Books) in the "M. The slider uses a spring-loaded ball contact against the windings.The larger Loose Couplers were sometimes called "Arlington" types since they could tune to the very long wavelengths for time signal reception (the Time Signal station was located in Arlington, VA and operated at VLF frequencies.) Arlington-type Loose Couplers will have a greater number of turns on the primary and secondary with larger coil dimensions.The Loose Coupler shown above is not marked but is almost certainly the Signal R-22 from about 1914. Murdock Company started in business in 1896 building various kinds of electrical equipment for telephone and telegraph service.