Hi Ted,

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The short answer is that both the calibration (master and BFO) settings can cause the filter to be misaligned with the signal.? Also, it can be a failure in the modulator in that one-half of the BAT54FL diode could have failed or other problems with the modulator.? If the issue is recent, it is most likely a failure rather than a bad calibration.

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I saw on your QRZ page that the v5 is running the KD8CEC software with a Nextion screen.? That makes it easy to do some checks and possible adjustments after saving the current configuration.? Can you pull up the software settings page and note the BO value?? It should be close to 11.056 kilohertz.? If not, I suggest using the Memory Manager software to save the current values and perform a complete recalibration.??

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I have always struggled using WWV as the calibration source as the sidetones get in the way of determining beat frequency.? I have a 10MHz standard that I use through an attenuator for the calibration source.? I also use a signal generator calibrated using the standard to verify accuracy.? The higher the calibration frequency, the better the accuracy.? If in a pinch, you can tune down to the commercial AM band and use a known station as the standard.? I have found this easy to do (other than all the turns of the tuning dial to get down to the station) but less accurate.

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If the calibration values seem correct, then the only test I know for the modulator is to pull the diode and replace it with a known-good one.? That does require SMD rework skills.? I suggest not using discrete diodes for this replacement, as they may not have the matched characteristics.

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Before you start tearing apart your radio, I have a question: The video clip shows USB as the communication mode.? Were you running a USB on 40 meters?

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73

Evan

AC9TU