Monday, October 26, 2015

Power meter and reference finished.

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.

No comments:

Post a Comment