[Elecraft] K2: RXVFO Waveform?

[Jim Miller]

While debugging a transmit output problem (cracked RFC13 found) I noticed 
that although the input to U3 is a nice sine wave the output (RXVFO) is 
distorted.

It has the proper gain (x2) but has what appears to be some higher order 
distortion on its way to the proper output level. Maybe second or third 
order. Definitely not oscillation. Power and ground to the IC is clean.

Is this due to the TUF-1 load as the diodes begin to conduct?

The input TXVFO is nice and clean so it makes me think the '1252 was put in 
this location just to handle the effect of the mixer non-linear load.

The receiver sounds great on 40M. I'm going ahead and tuning up the receiver 
on the other bands while waiting on the choke.

Or maybe I have another issue to debug...

73

jim ab3cv (pam shipped my rfc13 right after i called!!!)