A Look Back in History: Upgrading Radio Services in 1943

In mid 1943, wartime caution was in the air and the Peninsula Superintendent. For the San Francisco Water Department, it was warning against “trouble” and promoting new communications technology for the San Mateo Sheriff Office.

Memo of G.J. Davis, Superintendent of San Francisco Water Department, to the Federal Communications Commission.

In 1943, a Superintendent of the Water Department contacted the Federal Communications Commission to endorse the San Mateo County Sheriff’s Office request to the Commission for permission to use two-way radio equipment.

That same year, the U.S. Army Signal Corps compared the clarity and strength of AM versus FM radio signals. Using the same equipment except for the AM or FM circuitry, they drew the conclusion that FM was by far more reliant and clear. With FM, the signal was not subject to static interference from motors or other electrical sources.

Galvin Manufacturing Corporation had experience building Motorola FM mobile two-way radios for police cars. So they designed the SCR300 radio to work in the very high frequency (VHF) bands between 40-48 MHz and made it portable (35 pounds). They submitted it to the Signal Corps for testing and in 1943 Galvin began production.

With many troops stationed throughout the Bay Area – including in the SF Water Department’s watershed – it should be no surprise that the San Mateo County Sheriffs learned of this innovation in communications technology. There was a considerable level of concern in the region over the potential for sabotage and even innovations. No wonder Davis wanted to urge the FCC to allow the Sheriffs to utilize the new technology – for “trouble” or fire – to protect the people and the wartime infrastructure including Moffett Field, SFO, United Airlines, Hammond aircraft and the shipyards.

Soldiers using Galvin Manufacturing Corporation (Motorola) backpack portable FM two-way radio, model SCR300, 1943. Photo courtesy: Motorola (https://www.motorolasolutions.com/en_xa/about/company-overview/history/explore-motorola-heritage/first-fm-portable-two-way-radio.html).