90902 Cathode Ray Oscilloscope

The 90902 rack panel oscilloscope was part of a series which included the 90903 and 90905 models. The last digit of the model number represents the CRT size in inches. Thus, the model pictured above has a 2" CRT. These are basic scopes comprising the power supply and general brilliancy and focus units. For all practical purposes these were used with external sweep units such as the Millen 90921. However, as an AM transmitter monitor the user could feed modulated carrier RF into the vertical input via a pickup loop and audio modulation voltage to the horizontal input. By proper adjustment of levels well known trapezoidal monitoring patterns would result.

This 90902 belongs to Gary Carter, WA4IAM.