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2.5GHz field strength meter.


For this project your circuit board should be single sided. You may use double sided board if you have nothing else, just don't put anything on the reverse side copper and let the acid eat it away. You will find that it takes longer to etch your board because the acid has to eat away the extra copper. You may also require extra acid.



When you have finished etching the board, you will need a Schotky barrier diode or hot carrier diode. Solder it across the two antenna pads. Make two coils from enamelled wire, each coil is 5mm diameter and has 2 turns. Solder them to the pads as shown. Next solder the 470 ohm resistor and 1nf capacitor into place and finally the meter which should be a Micro Ammeter. You may also replace the meter for a simple LED. I don't think this will work for too well for low power wlan cards as the LED requires about 20mA to light up, but it might be worth a try. LED's usually cost less than a dollar, good panel meters are about $20.

This is a rather crude signal strength meter it works at very close ranges, and I find it works very well for determining antenna radiation patterns and gain. So don't expect to see the meter jumping up and down when you turn you wlan card on across the other side of the room.

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