Re: Simple spur fix

Warren Allgyer
 

And finally, here is a wider span showing 15 through 10 meters harmonic performance. My unit has the onboard filters completely removed and this scan was made with an external 30 MHz LPF plus the R27 filter. 

A clarification on the IMD comment in the last post. IMD was unacceptable at 100 mVrms audio drive before the filter was in place. It was not clear to me at that time whether the IMD was being introduced in the stages prior to the filter or after. If it was after, then increasing the audio input may be ok because it simply compensates for the insertion loss of the filter. If, though, the IMD was introduced in the SSB generator or the stages before that, then these pix may be a cure for the spurs but still have unacceptable IMD. Further testing is required to figure that out.

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