John,

Per your request I have modified the input coupling to the 2nd Mixer as follows:

· Remove C37

· Replace L15 and L16 with 16 ohm resistors

· Install 0.27 µH inductors from pins 2 and 3 of U8 to ground

I then retested the IF passband ripple by sweeping a 1 MHz span centered on 10.7 MHz.  The output level was reduced by 3 dB but there was no change in the ripple.  Click HERE to view my log.

I think we need to look outside of that coupling area since we’ve pretty much replaced every component.  Let’s replace both SAW filters next.  What do you think?

73,

Juan