Summary of THIS RF LISTENER LETS YOU HEAR THE RF SOURCES!
Maker Wolf built a handheld RF listener that converts a wide range of radio frequencies into audible sound without decoding them, revealing Wi‑Fi blips, radar chirps, microwave hums, and more. The design uses an AD8318 demodulator to output a logarithmic amplitude signal, which is filtered and amplified. During prototyping, the designer set a 224 mV reference for the op amp zero point and added a dedicated buffer for a chopper to avoid disturbing that zero-voltage point.
Parts used in the RF listener:
- AD8318 demodulator chip (breakout board)
- Op amp(s)
- Chopper (signal chopper circuit)
- Buffer amplifier for the chopper
- Filters (audio/RF filtering stages)
- Amplifiers (audio amplification stages)
- Handheld enclosure and power supply components
Have you heard about RF listeners earlier? If not, Maker Wolf has designed an RF listener that lets you hear the RF sources. When we look at the RF receivers, it usually singles out a particular frequency and decodes it. But in this project, the handheld device takes a range of frequencies and plays it as audio without decoding it into some type of information.
When you turn it on you immediately hear a whole forest of sounds; rapid blips from Wi-Fi, the intermittent chirps of airport radar, the drone of a microwave oven, and so on
says the Maker Wolf.
With this handheld device, you can now listen to a sound that you have never heard before.
When testing the schematic, the designer realized that it would not be possible to have a 0V = 0 signal for an op-amp circuit. The zero signal was made at 224mV, but when the actual prototype was tried, the chopper was disturbing the zero-voltage point. Hence the chopper was given its own buffer. The below figure shows the rewiring required to do this in the first prototype hardware.
At the heart of this wideband directional RF receiver is the AD8318 demodulator chip, of which the breakout board is available on Amazon that takes the RF signal as input and outputs the logarithmic amplitude signal. But before it becomes audible, the output signal is passed through several filters and amplifiers.
Read more: THIS RF LISTENER LETS YOU HEAR THE RF SOURCES!
- What does the RF listener do?
It converts a range of radio frequencies into audible sound without decoding them, letting you hear RF sources like Wi‑Fi and radar. - Which demodulator chip is used in the project?
The AD8318 demodulator chip is used to produce a logarithmic amplitude output from the RF input. - Does the device decode RF signals into data?
No, the device plays the RF frequency range as audio without decoding it into information. - Why was a 224 mV reference used?
The designer could not achieve a 0V = 0 signal for the op amp, so a 224 mV zero reference was used. - Why was a buffer added for the chopper?
The chopper disturbed the zero-voltage point in the prototype, so it was given its own buffer to prevent interference. - What processing is applied to the AD8318 output before audio?
The logarithmic amplitude output is passed through several filters and amplifiers before becoming audible. - Can the project reveal common RF sources?
Yes, turning it on reveals sounds from sources like Wi‑Fi, airport radar, and microwave ovens.
