Here is the latest toy that I finished. It is an active RF field strength meter. So far, I had a passive one (a detector which feeds into a microamperemeter). This one here has an op-amp stage plus a nifty VCO that outputs a sound that varies in pitch with the strength of the signal that was received.
The circuit follows the one published in Funkamateur 10/2010 by DK6UU. The circuit contains a bug as that is is published with the wrong type of chip (74HC4046 should be: CD4046).