I'm not going to call it a spectrum analyzer anymore - the way I've designed this, it isn't going to do the same things as a spectrum analyzer.
The main difference is that a spectrum analyzer can operate without a signal generator, this won't because the signal generator is what is going to tell the Arduino what the frequency is.
I built another shield to stack onto the shield in last week's post.
There is currently no connection from the DDS to this yet, but that's one of the only few things left to do on the hardware side.
I also built a filter that will ultimately be the first filter to test. This is for my Softrock 20/30/40 and should pass 7 MHz while filtering 14 MHz.
This will fit in a Radio Shack small plastic enclosure - the plate was leftover from a small dummy load that I glued into the enclosure.