[eagle] Passband Ripple - Latest Modifications and Test Results

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 http://www.juanr.com/pages/hobbies/ham_radio/Eagle/passband_ripple.htm 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