[Elecraft] Installed K3EXREF

[Paul Christensen]

Another benefit of the GPS-DO is that routine calibration to ensure 
long-term accuracy is the responsibility of the U.S. Department of Defense, 
and funded by U.S. tax payers.  Unless there's a hardware-related problem 
with the GPS-DO, calibration is someone else's problem and expense.  The 
user need only care that the unit has attained "Lock" status.

Paul, W9AC