Vintage Ham Scopes

摘要

Prior to 1935 hams relied on station monitors or used their receivers to check the quality of their phone signals.1 Unfortunately, not every station sounded good and a better method was needed. ARRL encouraged hams to clean up their signals and from the mid 1930s The ARRL Handbooks provided schematics, so hams could build a basic oscilloscope for phone station use. At about the same time the National Radio Company offered the CRO, a 3 inch model of similar design. At $29.50 plus the cost of the 3 inch 906 cathode ray tube (CRT) and one #80 tube, this was considerably more than the weekly wages of the average ham.