The Cushman CE-15 Spectrum Monitor is particularly designed for use in the Radio Maintenance field. It provides the user with the capability of visually monitoring a selected portion of the radio frequency spectrum lor the purpose of determining spurious emissions, intermodulation interference, unwanted oscillator radiation, and harmonic levels. This instrument can monitor and audibly identify AM and FM carriers, which is particularly useful in the case of interference. It may be used to check intermodulation distortion between RF signals, do IF and RF signal tracing and may be used as a field strength receiver when using a calibrated antenna. DESCRIPTION 1.02 The Spectrum Monitor is essentially a triple conversion superheterodyne receiver with a video display as well as an audio output demodulated from either AM or FM signals. The frequency range Is from 1 to 1000 MHz. It has four scan widths, 10 kHz, 100 kHz, 1 MHz and 10 MHz per division. It also has a selectable 2 kHz bandwidth filter on the 10 kHz scan width range to reduce noise when viewing low level signals. 1.03 An LED frequency display with Coarse and Fine tuning controls provides for accuracy in setting the center frequency of the display and a graticule calibrated in 10 dB per step divisions makes it possible to view a 70 dB amplitude signal. Its high sensitivity, -115 dBm (0.4/µV), permits viewing extremely low level signals. 1. 04 Front panel access to an internal level and frequency reference makes it possible to maintain a level accuracy of measurement of better than ± 3 dB. It is possible to introduce an external calibrated signal from an accurate source such as a CE-6A Communications Monitor for use as a frequency calibrating marker simultaneously with the signal being monitored. 1.05 Sweep rate and IF filter controls have been eliminated. These arc set to their optimum value for each range selected. A first IF of 2100 MHz eliminates problems from image frequencies, since they will be 1.2 GHz away from the frequency of interest.