I finished up the AD8307 power meter and -10dBm reference.
For the reference I soldered some .020 in double sided circuit board material around the outside edges to protect the components. Since this will not be used very often I decided to not put in a switch, I just glued the assembly to a 9V battery holder.
I have a new circuit board layout with room for mounting holes that I will build for use as an internal reference in the Spectrum Analyzer I am working on.
After a little cutting and a lot of sanding and touch up work I painted and printed some decals for the Altoids tin I used to house the Power meter.
According to the readings on my oscilloscope the reference should be within 1 dBm of the desired -10 dBm. After setting the calibration values in the Arduino sketch for the power meter, the readings are consistently within .5dBm. Checking linearity with several in-line attenuators all readings were within 1dBm.
Without access to other calibrated standards, this is about as accurate as I can come up with, and should be accurate enough for checking most things an amateur would build.
Now to get back to the spectrum analyzer build.