VGA 3 12 dB gain I channels

12 dB half wave so 18 dB gain predicted. 

Expected is 30 db 

BIG BIG Tia mistake ! Picked 85 ohms input !! Loading the previous stage !!

VGA 2 measurements :

The VGA 2 output seems fine- but the mixer is giving errors. 

Trying to make input differential.

Arrange the inputs symmetrically !! 

Better at canceling noise. :) 

50 ohms terminations -

Checking differential input to VGA 2

Cool :$ 

Mischief managed :)

VGA 1 measurements

Dc blocker to prevent spectrum analyzer from destroying