“So what is this thing? Basically it’s a handheld device that allows you to “hear” RF sources. Regular rf receivers single out a particular frequency and decode it into some type of information. This device on the other hand picks up everything, and plays it as audio without any decoding.
When you turn it on you immediately hear a whole forest of sounds; rapid blips from wifi, the intermittent chirps of airport radar, the drone of a microwave oven, and so on. It’s like gaining access to a whole world of sound that ordinarily cannot be heard.
The design is based on the AD8318 demodulator chip, I bought a breakout board from Amazon. This chip has an RF input, and outputs a logarithmic amplitude signal. I take that signal and run it through various amplifiers and filters to turn it into something audible.
The other off the shelf part is a TSA900 antenna. It’s broadband (900MHz-12GHz) and directional which is perfect for my project.”