This is a 1930s vintage letter from "Universal Radio Service" in Long Beach, Calif., dated December 3, 1936, mailed to a radio specialist in San Diego regarding "grinding a crystal to a frequency between 19 and 20 meters." The letter is one page, measures 8 1/2" x 11", typed, signed in pen, and blank reverse. Condition: The letter was mailed as originally folded, with a crease in the bottom right corner (see scans). See my listings for other unusual and interesting vintage items. Multiple purchases are combined with a single postage charge. All items are shipped sleeved in plastic, and packaged between sturdy cardboard. This item will be shipped flat.

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