‰  NOW 30 WPM  ‰  TEXT IS FROM SEPTEMBER 2015 QST  PAGE 44 ‰

ZERO FREQUENCY?  IN REALITY, YOU HEAR THE TYPICAL RESIDUAL AUDIO PRODUCTS
PRODUCED BY THE AUDIO AMPLIFIER WHEN THE AUDIO SIGNAL IS APPROACHING THE
LOWER LIMIT OF THE AUDIO PASSBAND.  UNDER THE BEST CONDITIONS, THAT
PROCEDURE WILL GET WITHIN 20 HZ.  WHILE THAT WAS ADEQUATE IN PAST YEARS, IT
IS FAR FROM IDEAL TODAY, WITH TRANSCEIVER DISPLAYS CAPABLE OF READING TO 1
HZ RESOLUTION.  WHEN TRANSMITTING SSB WITH LOW FREQUENCY CONTENT IN THE 100
TO 150 HZ RANGE, YOU CAN DEFINITELY HEAR A VFO CHANGE OR DISCREPANCY OF 10
HZ.  YOU CAN ACHIEVE A HIGHER DEGREE OF FREQUENCY ACCURACY USING EQUIPMENT
TYPICALLY FOUND IN MOST HAM STATIONS.  THE BASIC REQUIREMENTS ARE A
COMPUTER, A SOUND CARD INTERFACED BETWEEN THE COMPUTER AND THE RADIO, AND
READILY AVAILABLE SOFTWARE PROGRAMS THAT ARE TYPICALLY USED FOR DIGITAL
SOUND CARD MODES SUCH AS PSK31.  YOU MUST ALSO BE ABLE TO RECEIVE WWV.
ONCE YOUVE SET UP YOUR EQUIPMENT, YOU CAN USE THE INFORMATION PRESENTED BY
THE COMPUTER SOFTWARE TO DETERMINE FREQUENCY ERRORS.  DIGITAL MODE SOFTWARE
APPLICATIONS, LIKE FLDIGI, ARE AVAILABLE FOR FREE.  YOU CAN USE ANY OTHER
SOFTWARE APPLICATIONS THAT PROVIDE A NUMERICAL VALUE FOR THE AUDIO
‰  END OF 30 WPM TEXT  ‰  QST DE W1AW  ƒ