Here is a link to a circuit that works fine detecting ectromagnetics waves power.

I probed and it detect my rooter 2,4 GHZ very well, my telephone mobile when I call, a FM transmitter I built for testing it (I will frequency to see if the i can probe V2Skull ) and with my microwave.

I made the circuit in a protoborad so I didn't need to soldier cables, and added a last stage of amplification, because he only uses 2 of the 4 ports from LM384 amplifier. Use 4,7 K from third amplifier to GND , and 20k + 50 K variable resistor from third output to third negative ampli. The positive thirdìnput takes from the output of that circuit

I probed with 9V battery (and with 5V Arduino microcontroller) with third output connected to multimeter and to Arduino Analog Input Pin.

The idea is try to detect if My body is emmiting signals, and also see if it detects microwave when I am burned (or to see if the whistle in my ears come from ultrasound or microwaves). I will post as soon I have the conclusions. Ah, add a 50 ohms resistor bettwen anntena (a simple cable for protoboard) and GND.