[Lear Developments telephone transmitter]

Composite photograph of a Lear Developments telephone transmitter, showing views of the internal components and the external case, circa 1931-1939. The verso inscription, which was written by William P. Lear, states that this was the first 3105-3120 kc 35-watt telephone transmitter made for private pilots.

Inscription on verso: "The first 3105-3120 KC 35 watt telephone transmitter ever made for private fliers. Previously W. Elec. Co. was only source and had vertical monopoly of aviation communication -- I defied their patent monopoly and [illegible] out this 35 watt light weight pentode modulation unit -- mounted it in a 1933 Waco - Continental powered unit and went to Calif from NY - enroute many CAA stations heard a private aircraft on 3105 for the first time. WPL."