Under the F6 settings, set the "Set Time Using Digital Input" and "WWVB Mode" to Yes.
You should also turn the debug mode on by pressing the "D" key when you're at the
main SDR screen. The "D" key toggles the debug mode on and off. After making the changes,
exit out of SDR and connect up the WWVB receiver. Restart SDR and hopefully it will lock up
if you can find a good location for the antenna. If you are in the debug mode, you should see
a message saying that SDR has lock to the WWVB time. When SDR locks to the WWVB time, you
will see "(L)" next to the UTC time display at the bottom of the screen.
After lock up, SDR will continually poll the WWVB receivers time code. If the internal
SDR time gets off by +-15 milliseconds or more it will set its time to the WWVB receiver
time.