‰ NOW 40 WPM ‰ BETWEEN THE ACTUAL RECEIVED FREQUENCY AND THE RADIO DISPLAY. LOWER SSB MODE NEXT, CHANGE TO THE LOWER SSB LSB MODE WITHOUT CHANGING THE RECEIVER TUNING AS DETERMINED IN THE PREVIOUS STEP. AGAIN, OBSERVE THE NUMERICAL TONE VALUE. NOTE ANY DISCREPANCY IN THE DECODED FREQUENCY. IF THE LSB DECODED FREQUENCY IS NOT THE SAME AS THE USB DECODED AUDIO FREQUENCY, THEN YOUR RADIO HAS A BFO FREQUENCY ERROR, WHICH REQUIRES FURTHER ATTENTION. IN OLDER RADIOS THE USB AND LSB BFOS MIGHT 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 TRANSMIT AND RECEIVE ON FREQUENCY BE CERTAIN OF YOUR DISPLAYED FREQUENCY WITH THIS EASY CALIBRATION TECHNIQUE. BOB MCGRAW, K4TAX WHILE PARTICIPATING IN HF SSB AND CW NETS AND MAKING CONTACTS, I HAVE OBSERVED THAT SOME STATIONS ARE NOT ON FREQUENCY. UPON INQUIRING WITH THOSE STATIONS OPERATORS, I HAVE FOUND THAT THE STATIONS RADIO DISPLAY SEEMS TO INDICATE DIFFERENTLY FROM MINE. WITH TODAYS PRECISION NOT TO BE CONFUSED WITH ACCURACY ED. RADIO DISPLAYS, I OFTEN HEAR COMMENTS ON THE AIR SUCH AS, YOU ARE 36 HZ LOW. YET ANOTHER STATION RESPONDS, IM ON 7,250,000 HZ, SO YOU MUST BE 36 HZ HIGH. IN REALITY, AS COMPONENTS AGE, THE RADIO DISPLAY MAY NO LONGER INDICATE THE ACTUAL TRANSMIT OR RECEIVE FREQUENCY. THIS ARTICLE DESCRIBES A METHOD FOR CHECKING YOUR RADIO FREQUENCY ACCURACY AS COMPARED WITH THE DISPLAYED FREQUENCY. YOU CAN ALSO USE THIS CALIBRATION METHOD WITH THE ARRL FREQUENCY MEASUREMENT TEST. I ENCOURAGE YOU TO BECOME FAMILIAR WITH ANY RELATED PROCEDURE FOR YOUR SPECIFIC RADIO BEFORE TWEAKING ANY INTERNAL ADJUSTMENTS. FREQUENCY STANDARDS WE CAN COUNT ON THE NATIONAL INSTITUE OF STANDARDS AND TECHNOLOGYS NIST WWV RADIO TRANSMISSIONS AS A RELIABLE FREQUENCY STANDARD. IN ONE METHOD, ZERO BEAT YOUR RECEIVER TO THE WWV STATION USING THE VFO, WHILE LISTENING TO THE AUDIO TONE AS IT DIMINISHES IN FREQUENCY TO ZERO. WE MUST ASK OURSELVES, HOW CAN YOU HEAR ‰ END OF 40 WPM TEXT ‰ QST DE W1AW ƒ