Zenith "Radio Nurse"

The "Radio Nurse" was a wireless intercom system introduced by Zenith in 1937 as a baby monitor.  It was developed in response to the kidnapping of the Lindbergh baby, and the media-circus trial that followed.

The complete system consisted of a receiver, the Radio Nurse, and the transmitter, the Guardian Ear.

Zenith commissioned the Japanese-American artist and designer, Isamu Noguchi, to design the receiver unit.  The result was this stylized human nurse's head molded in brown Bakelite.  Noguchi explored the notion of the interchangeability of biological and machine forms, and the role of everyday objects as sculpture.  The Radio Nurse is quite typical of his work. 

Sadly, many of these unique devices were trashed following Pearl Harbor because of the Japanese name on the case.  Noguchi, in fact, was a U.S. citizen, born in Los Angeles in 1904, though he lived in Japan from 1907 through 1923.  His mother was American.

These units are rare and in great demand by collectors of 20th Century art.

Radio Nurse Label

"Design by Noguchi"

Totally unlike the receiver, the transmitter was housed in a plain metal case.  The "ear" was a crudely-made condenser microphone seen at the front of the chassis.  This was suspended by springs to avoid noise pickup.  The hole just above the grill allowed a screw to be inserted which secured the microphone during shipment.

The microphone's output was amplified and used to modulate an oscillator operating at 300 kHz, and that signal was coupled to the AC power line.  The receiver picked up that signal from the power line, demodulated and amplified it, and fed it to a speaker. 

The Guardian Ear Chassis
The Radio Nurse Chassis

The Radio Nurse was announced in the trade publication "Radio Today" in the March, 1938 issue.  Note the very cool Donald Duck toy on the shelf!