Well who don’t know WWVB stands for station that transmits exact time signals so radio controlled clocks could synchronize and display very accurate time. The actual signal is a 60kHz carrier that is AM modulate with time code. So local clock has to receive, demodulate and decode time signal in order to synchronize time.
This clock project receives time signal from WWVB, Fort Collins, CO and synchronizes each time a new signal is received. If signal is lost, it keeps counting locally until next synch signal is received. All features are programmed in to PIC 16F628 microcontroller that also displays time on 6 seven segment displays. The AM receiver is a C-MAX model CMMR-6 that works with loopstick antenna which actually can be built by you. Put everything in to nice enclosure and forget about time setting problem – it always shows atomic time.