It looks good, so I must test it, what is q3 type, and the frequency rang of detection?Hello,
Have a look at the following circuit:
http://www.qsl.net/va3iul/Homebrew_RF_Circuit_Design_Ideas/Field_Strength_meter_3_level.gif
It uses a selective tuned input circuit, Q1,2 and 3 are RF amplifiers, then a detection takes place and then a level display.
The circuit comes from this page with a heap of RF circuits:
http://www.qsl.net/va3iul/Homebrew_RF_Circuit_Design_Ideas/Homebrew_RF_Circuit_Design_Ideas.htm
Bertus