[Elecraft] KX3 VFO tuning noise reduced or eliminated

[Wayne Burdick]

Mike WA8BXN <hubby2k at hotmail.com> wrote:

> The instructions suggest that realignment of the filter may be necessary if some of the capacitors are pressed on the board. Is there any simple way to tell if such realignment is necessary?

As long as you handle the module carefully and don't press down hard on the large, white, rectangular film capacitors on the back side of the module, there should be no need to do any realignment. 

If you're concerned, you could spot-check opposite sideband suppression on 20 meters. To do this, first go to CW normal mode and normalize the filter passband (400 Hz, centered). Next, tune in a strong signal in the clear (S9 or so), check the S-meter reading, then tune the VFO downward by an amount equal to your sidetone pitch x2. Recheck the S-meter reading. Typically it will be 50 dB or more down (where an S-unit is about 5 dB). Sideband suppression can vary a bit with pitch, filter, and AGC settings, but this will give you a rough idea if the module is still properly aligned.

There an app note on our KX3 web page describing all-band RXSBNUL alignment. This can be done manually (with any RF signal generator), or in an automated fashion when used with an Elecraft XG3.

73,
Wayne
N6KR