Frequency Counter

Overview

A frequency counter measures the repetition rate of an input signal by counting cycles over a known gate time. In a station it is used to verify that a transmitter is actually on the frequency it claims, to check a signal generator, or to measure an unknown oscillator.

The accuracy of the measurement depends entirely on the accuracy of the counter's own timebase. A basic crystal reference is good to a few parts per million; a temperature-compensated oscillator is good to a fraction of a part per million; a GPS-disciplined reference is accurate to the point where the counter is no longer the limiting factor.

Bands and modes

Band coverage

Modes

Safety note

Using it well

• Use a 10 second gate when you need maximum resolution.
• Check your transceiver against the counter once a year and note the offset.
• Feed the counter through a dummy load tap, never directly from the transmitter.
• Lock to an external reference if you need absolute accuracy.