An RTL-SDR stick is the cheapest way to see real radio signals: a USB receiver the size of a thumb drive for about $40 to $60. With Consentiva it turns an Android phone or a laptop into a walking spectrum analyzer for the bands most people care about: FM, aviation, marine, public safety, 433 and 915 MHz devices and the lower cellular bands.
What it covers, and what it doesn't
The stick's R820T2 tuner receives roughly 24 MHz to 1.7 GHz. That includes most of what a street walk finds, but not Wi-Fi at 2.4 and 5 GHz, the higher cellular bands or mid-band 5G. For those, use a HackRF. For AM and shortwave below 24 MHz, use the RTL-SDR Blog V4.
What to buy
- An RTL-SDR stick with an R820T2 tuner (Nooelec NESDR SMArt or RTL-SDR Blog V3), usually sold with a small antenna kit.
- A USB-C to USB-A OTG adapter that carries data, for a phone.
- Optionally a better antenna and a power bank for long walks. See what to buy.
First connection
- Screw the antenna onto the stick's SMA jack, and plug the stick into the phone through the OTG adapter.
- Open consentiva.xyz/app in Chrome and sign in.
- Under Receiver choose RTL-SDR stick, then tap Start walk and pick the device in the box Chrome shows.
- If Chrome says "No compatible devices found", open the app's Set up your Android phone for the receiver steps and tap Test USB connection.
On a laptop, Chrome or Edge works the same way. On Windows, do the one-time WinUSB driver step with Zadig (the app walks you through it).
Check it with a known signal
Sweep 88 to 108 MHz where you can get FM radio. You should see peaks at the local stations. Pull the antenna off and the peaks should drop clearly: if they don't, check the connection before trusting any other reading.
Gain and overload
The stick's converter has only 8 bits, so a strong nearby transmitter can overload it and make signals appear across the whole screen. Consentiva uses a fixed gain, never automatic, so levels stay comparable between walks; if every channel looks lit up, lower the gain. Use the same antenna for every walk and record it in the Antenna setting.
Be realistic
RTL-SDR support in Consentiva is a beta. Readings are uncalibrated (dBFS) unless you enter your own calibration offset, and a walk shows what is present, not who is transmitting; most signals around buildings and vehicles are legitimate. Next: how to survey the radio signals around you.
Common questions
What can an RTL-SDR stick receive?
About 24 MHz to 1.7 GHz: FM and aviation, marine and public-safety radio, 433 and 915 MHz devices and the lower cellular bands. It doesn't reach Wi-Fi, the higher cellular bands or mid-band 5G; for those you need a HackRF.
Which RTL-SDR sticks work with Consentiva?
Sticks with an R820T or R820T2 tuner, such as the Nooelec NESDR SMArt and the RTL-SDR Blog V3, work as the plain RTL-SDR receiver. The RTL-SDR Blog V4 has its own receiver choice, because it also reaches HF. Both are beta.
What cable or adapter do I need for a phone?
A USB-C to USB-A OTG adapter that carries data. The stick has a USB-A plug on one end and an SMA antenna jack on the other.
Why does Windows need Zadig?
Chrome can only use a USB receiver that has Microsoft's WinUSB driver. A one-time driver swap with the free Zadig tool installs it; RTL-SDR sticks always need it on Windows.