Hammarlund

Lore & Background

Hammarlund began as a loft operation on Fulton Street in Lower Manhattan, manufacturing radio components. Its variable capacitor designs became industry standards, and the schematic symbol for a variable capacitor was adopted as the company's logo. In the mid-1920s, the company formed a partnership called Hammarlund-Roberts Co. to offer kits for AM broadcast radios using Hammarlund parts. After that partnership ended in 1931, Hammarlund entered the shortwave receiver market with the Comet Pro, the first commercial short wave superheterodyne receiver, used by professional listening posts and on major exploration expeditions.

An improved receiver, the Super-Pro (SP-200 series), went into production in 1936. During World War II, Hammarlund expanded, manufacturing Super-Pro receivers (Signal Corps model BC-779) and producing variable capacitors at a rate of one million per month. After the war, the market was flooded with surplus receivers. In 1947, the SP-600 Super-Pro receiver was introduced, covering 540 kHz to 54 MHz with a calibrated mechanical band spread, and was widely used for military, laboratory, and commercial applications.

Hammarlund also produced a number of transmitters, though these saw only limited use. The company built substantial quantities of VHF FM 'Village Radios' for the United States Agency for International Development for use in Vietnam, as well as land-mobile radios and Citizens Band transceivers. The company underwent frequent ownership changes starting in the late 1950s, being sold to Telechrome, then Giannini Scientific, and finally to Electronic Assistance Corporation in the late 1960s. The product line was sold off or phased out, and the Cardwell Condenser Corporation purchased all remaining stocks. The factory closed in 1973.

Reader's Guide

Hammarlund's significance lies in its longevity as one of the United States' oldest radio manufacturers and its contributions to radio technology. The company's variable capacitor designs set industry standards, and its schematic symbol became its logo, reflecting the component's importance. The Comet Pro receiver marked a milestone as the first commercial short wave superheterodyne receiver, used in professional listening posts and on major expeditions. The Super-Pro series, particularly the SP-200 and SP-600, saw extensive military and commercial use, with the SP-600 covering a wide frequency range and featuring a calibrated band spread. During World War II, Hammarlund's capacitor production reached one million per month, underscoring its role in the war effort. The company's later products included VHF FM radios for Vietnam and Citizens Band transceivers. Despite frequent ownership changes after the late 1950s, Hammarlund's legacy endures through its receivers, which are collected, restored, and used by vintage amateur radio enthusiasts. The company's name is sometimes linked to the origin of the term 'ham' for amateur radio operators, though this etymology is disputed and considered an example of corporate wishful thinking.

Did You Know?

• Hammarlund's variable capacitor schematic symbol was adopted as the company's logo.
• The Comet Pro was the first commercial short wave superheterodyne receiver.
• During World War II, Hammarlund produced one million variable capacitors per month.