I built the circuit from the page below.

http://www.atvinderby.co.uk/2.4Ghz_SWR_Meter.htm

The I get 0v out when held near my wireless router, if
I put it near the microwave oven, the high input impedance
meter bounces up and down between 7mv and 80mv and
everything in between.
I used a 1N416E diode and a 1500pf filter capacitor. The
tuning cap doesn't have any affect.
Should this circuit work? If so what could I be doing wrong?

Mike