‰  NOW 13 WPM  ‰  TEXT IS FROM SEPTEMBER 2015 QST  PAGE 45  ‰

MIXER OSCILLATORS ARE CRYSTAL CONTROLLED AND USE A PLL TO LOCK THE
FREQUENCY TO THE MASTER OSCILLATOR.  YOU MIGHT FIND THAT THESE STILL ALLOW
SOME SMALL ERROR ON ONE BAND WHERE AN ERROR DOES NOT EXIST OR IS OF A
SLIGHTLY DIFFERENT VALUE ON OTHER BANDS.  TYPICAL MULTIPLE BAND FREQUENCY
ERRORS ARE SHOWN IN TABLE 1.  CONCLUSION YOU SHOULD HAVE A TRACEABLE SOURCE
FOR YOUR FREQUENCY MEASUREMENT.  USING THE ABOVE DESCRIBED METHOD, WE HAVE
A USEFUL CALIBRATION THAT IS TRACEABLE TO WWV TRANSMISSIONS.  ALTHOUGH THE
ƒ  QST DE W1AW  ‰
FREQUENCY ACCURACY CAN BE BETTER THAN ONE PART IN 1013 AT THE WWV
TRANSMITTER, PRACTICALLY AND INSTANTANEOUSLY IT IS ABOUT 0R1 PPM WHEN
RECEIVED AFTER YOU TAKE SIGNAL TO NOISE RATIO, DISTANCE, AND ATMOSPHERICS
INTO ACCOUNT.  WITH THESE MEASUREMENTS AND SUBSEQUENT ADJUSTMENTS, YOU WILL
HAVE A HIGH DEGREE OF CONFIDENCE THAT THE DISPLAY ON YOUR TRANSCEIVER IS
ACCURATE WITHIN A FEW HZ.  ARRL MEMBER ROBERT MCGRAW, K4TAX, HOLDS AN
‰  END OF 13 WPM TEXT  ‰  QST DE W1AW  ƒ