I just discovered that Martin Roberts designed a very nice RF scanner and signal strength meter (SSM) using an emonGLCD. With one very simple hardware modification (you will loose the ability to use the LDR though), you can get the emonGLCD to work as a RF scanner ! All instructions are here. I followed them and within minutes, I got my RF scanner working !

The softwaremake the scanner easy to use and configure using the three emonGLCD push-buttons. You can configure the following parameters

• Trigger level : minimum signal level required to trigger the display
• Trigger position : position on the display of the signal that caused the trigger
• Base level : minimum signal level which can be displayed (-80 or -100dBm)
• Glitch detector : with this on short signal pulses which could be missed by a normal scan will show up
• Timebase : period of a complete scan across the screen (16ms-16s)

Here are screenshots at  respectively 16ms, 32ms, 128ms and 16s :

Very nice !