This counter module was especially designed for servicing and calibrating mobile communications equipment and AM & FM broadcast equipment. An automatic gain control (AGC) amplifier has been provided on the 80 MHz channel. This provides ease-of-use by compensating for input level variations and rejecting noise up to 50% of the peak-to-peak level of the input signal. The front end circuitry of the 525 MHz channel is fuse-protected against high input signal levels that would normally cause expensive front end damage. The addition of the battery pack makes this an ideal portable instrument for the lab or the field.