The FS700 LORAN-C Frequency Standard produces a highly stable and accurate 10 MHz output by locking an internal crystal oscillator to the Cesium clock controlled LORAN-C radio transmission. The FS700 system consists of a receiver, containing amplifiers, filters, and data acquisition circuitry, and a remote antenna, with an internal preamplifier. Data acquisition circuitry allows the FS700 to frequency lock its internal oscillator to the third positive zero crossing of the LORAN-C transmission. In addition to providing an ultra-stable 10 MHz output, the FS700 also provides a user selectable TTL compatible frequency output in the range of 0.01 Hz to 10 MHz in a 1, 2.5, 5 sequence. An internal phasemeter circuit allows precise frequency calibrations of other oscillators in the range of 100 kHz to 10 MHz.