What is the GPSDO and what benefit does it provide?

First, an explanation of what a GPSDO is: Most oscillators that are used as the frequency reference for a radio will drift over time. If you purchase a radio with a crystal oscillator, a temperature controlled crystal oscillator (TCXO) or an ovenized crystal oscillator (OCXO), you will notice that over time these will drift. An adjustment is required every six to twelve months to keep them on frequency. ALl these crystal oscillators have excellent short term stability but poor long term stability. The GPS system is designed to keep time very accurately, but at the multi-nanosecond range. Over time, GPS has perfect stability (long term), but in the short term it is a fairly poor reference. A GPSDO combines the best of both of these worlds: It uses a base oscillator with good short-term stability (a TCXO) and then uses a GPS to adjust it over time, or discipline it, to stay on frequency. With a GPSDO you have excellent short and long term stability. The optional GPSDO in the FLEX-6000 Signature Series radios provides both frequency and time information to the radio. The 10MHz output of the GPSDO is used as the reference for the master clock in the FLEX-6000 ensuring the radio is always on frequency. The time information can be used in the future for a number of situations where time information is important in communications and station operation.