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30 results

[Learadio Type TR-50 transmitter] (Item)

Photograph of a Learadio Type TR-50 transmitter, showing views of the internal components and the external case, circa 1931-1939.Typed caption on verso: "T. Shows the original effort to make a more powerful transmitter by using tubed in parallel. This was a two-frequency transmitter and operated on 3105 and 3120 KCs."

[Learadio aircraft communications system] (Item)

Photograph of a Learadio aircraft communications system, circa 1931-1939. Specific devices pictured include the Model MOPA transmitter (emitator acord unit) and Model R2BB receiver (receptive accord unit).Caption: "Typical aircraft communication system."

[Chassis of Model L Lear-o-Scope] (Item)

Photograph of the chassis of a Model L Lear-o-Scope, circa 1931-1939. The verso inscription, which was written by William P. Lear, describes the development of the device.Inscription on verso: "Here is chassis of Model L Lear-o-Scope. The layout was done by WPL -- Wilbur Webb - now deceased who left me and went to Bendix - and Fred [Coombs?] who could layout and draw up such a unit in a maximum of…

[Model L Lear-o-Scope and loop antenna] (Item)

Photograph of a Model L Lear-o-Scope and loop antenna, circa 1936-1939. The verso inscription, which was written by William P. Lear, describes the device and its development.Inscription on verso: "Note left crank changed bands and moved mash on dial -- Right crank for tuning -- moved freq. dial 200 to 410 KC -- 530 to 1530 KC. Also first time tuning meter used. High Z loop with short tuning coil…

[Learadio Model R-3 aircraft receiver, antenna, and peripheral components] (Item)

Photograph of a Learadio Model R-3 aircraft receiver, shielded loop antenna, and peripheral components, circa 1931-1939. The caption describes the device's development.Typed caption on verso: "P. This loop was metallized in an attempt to shield it, but it was found that the metallizing reduced the 'Q' of the loop so much that it was completely impractical. It was also used in conjunction with an…

[Learadio Model R1 receiver and headphones] (Item)

Photograph of a Learadio Model R1 receiver and headphones, circa 1931-1939. The device is on scale to demonstrate its light weight. The caption describes the device's development and specifications.Typed caption on verso: "C. A Model R-1 battery-operated receiver, which had very good sensitivity. As you can see, it weighs a little less than 16 1/2 lbs, complete with batteries and headphones. It is…

[Learadio T-30 and R-3 equipment] (Item)

Photograph of a Learadio T-30 R3 radio system and assorted components, circa 1935-1939. The inscription notes that this equipment was developed especially for pilots operating in Alaska.Inscription: "Learadio T-30 R3. Saved many lives and much money for bush pilots in Alaska and northern Canada. Designed in 1935 especially for Alaska flyers. / Trans. 2-freq. -- 3105 6210 and others. Plug-in…

[Assorted Learadio devices] (Item)

Photograph of assorted Learadio devices, circa 1935. Pictured devices include the Model R-3 aircraft receiver, T-30 radio unit, and a shieled loop antenna.Inscription on verso: "Lear equip / circa 1935."

[Learadio remote controller and transmitter remote control] (Item)

Photograph of a Learadio remote controller and transmitter remote control, circa 1936. The caption describes the devices' specifications and utility.Typed caption on verso: "O. (circa 1936) A picture of both the combination remote controller and the transmitter remote control. You will note there were blank spaces on the transmitter selector dial to write in the particular frequencies of the…

[Learadio loop antenna] (Item)

Composite photograph of a Learadio loop antenna, showing two views of the internal components, circa 1931-1939. The caption describes the antenna's development and specifications.Typed caption on verso: "H. Shows an early attempt to tune the loop antenna at the antenna, itself, to eliminate the losses attendant to a long loop line. Also you will note that there were two loops in the fore and aft…