Cushman CE-50A / CE50A / CE 50A AM / FM Communications Monitor

The Cushman CE-50A Communications Monitor is a portable test instrument designed to aid in the repair of two-way radios operating in the VHF / UHF range to 1000 MHz. Besides measuring carrier frequency and modulation characteristics of transmitted signals , it can measure SINAD receiver sensitivity, transmitted RF power, and display demodulated audio frequencies on its internal oscilloscope for visual-signal monitoring. The unit is automatically self-calibrating in the monitor mode, and its full-service power supplies allow its use at unpowered remote sites (by vehicle power or optional battery) as well as in the shop.

The CE-50A monitor section is a sophisticated triple conversion superheterodyne receiver. The input has an adjustable sensitivity for monitoring signals of 2mV to 500 mV in level. This allows the testing of a transmitter output signal at any distance from a few feet to several miles.

The CE-50A also generates accurate RF signals for testing sensitivity, alignment and performace of radio receivers. The generated RF can be transmitted as the CW signal, or can be AM or FM modulated by an audio frequency tone synthesizer. It can also be Pulse Frequency modulated by an external signal. Modulation can be selected in continuous or timed interval (burst) durations. There is also a simultaneous 1 kHz + Tone Generator modulation capability to help with signal tracing and receiver alignment.

The signal generator section is a highly accurate frequency synthesizer with a frequency range of 100 kHz to 999.999 MHz. Its output can be connected directly to a transceiver, and is protected from accidental transmitter keying by an automatic electronic circuit breaker. An output level from .1 mV to 300 mV rms is selectable at the front panel through precision attenuator switching.

There are also front panel switch positions on the CE-50A for the CE-50-A Spectrum monitor functions. The switch positions used for spectrum monitor functions are identified in yellow and should be avoided when making measurements unless called for.