I've verified each of the 3 mixers that I need for the spectrum analyzer. The one above is mixer 2. The schematic for this mixer is available from Scotty's site.
I've also verified mixer 1 against the schematic. There have been 2 optional revisions posted that aren't included on mine. I'm going to add them later, but only if necessary.
Finally, mixer three is complete, and verified against the schematic. This one isn't strictly needed for the spectrum analyzer, however it is necessary for the tracking generator. A tracking generator is a module that generates a signal that matches what the analyzer is tuned to. This is useful for tuning filters, or other two-port devices.
I'm missing some parts that I need to complete the control board. I hope to get replacements soon, so I can begin testing some of these modules… Stay tuned!