Tektronix 101 Video Calibrator
Tektronix engineer Frank Hood recollects:
A point that I might mention here is that the Type 511 was not the first instrument built by Tektronix. Actually the first instrument offered for sale was a calibration standard, designed and built by Howard, and called a Type 101 Calibrator. This instrument was used in the test department for many years to assure the accuracy of all instruments. Every scope was hand calibrated. The person doing the testing put pencil marks on blank dials, John Larson, then engraved each dial according to this calibration.