Police detector for Android

Know where the police are. Before they see you.

Your phone beeps when a police car, ambulance or fire truck near you uses its radio. Unmarked cars too.

Get Tetra Hunter — from €29.99 Try the free demo

Works with a small USB receiver + antenna, sold separately. See the kit

Set up in 10 minutes
Android 8 or newer
One payment

Try the app right here

Tap the buttons, scroll and open Settings — it’s live.

Tetra Hunter

Stopped

Rotate phone for fullscreen.

RX1

380.000 - 382.500 MHz● Idle

Status: stopped | margin 12 - 33 dB | IQ --

RX2

382.500 - 385.000 MHz● Idle

Status: stopped | margin 12 - 33 dB | IQ --

RX1 FLOOR--

RX2 FLOOR--

MODECITY

Spectrum / waterfall

No receiver connected

Debug

RX1

Waiting for RX1 diagnostics

RX2

Waiting for RX2 diagnostics

System

Waiting for system diagnostics

Detector Main Settings

City mode thresholds

First green threshold12 dB dB above noise where the green LED alerts. Lower = more sensitive. LED spacing1.5 dB dB between each strength LED. Wider = only stronger signals climb the bar.

Alarm sound outputBluetooth uses connected audio; otherwise phone.

Alarm sound level100%

Advanced Detector Settings

Dynamic Receiver Gain (dB)On adjusts RTL-SDR gain automatically. Off uses the manual value below.On

If you get false positives, talk with Letoa93 on Discord before touching receiver gain.

Contiguous FFT (100% coverage)On = max burst coverage, more CPU. Off = manual hop timing. Applies on next Start.On Extra TETRA criteria0 Contact Letoa93 on Discord before changing. Downlink channel blacklist3 Max channels muted at once. ON/OFF is on Monitoring.

Blacklist list filePermanent muted MHz lines.

RTL-SDR Devices

Enable second RTL-SDRUse RX2.On Receiver 1 start (MHz)Receiver 1 end (MHz) Receiver 2 start (MHz)Receiver 2 end (MHz) PPM correction Bias-T RX15V antenna power.OffBias-T RX25V antenna power.Off

Max span: 2.56 MHz per receiver.

General settings

Dark themeOnLock to portraitLocks portrait and disables fullscreen.Off UI scale100% Battery/CPU optimizationSaves battery: throttles UI and removes spectrum/waterfall. Detection unchanged.Off Allow the app to work in backgroundKeeps detecting + alerting when the app isn't open.Off

RGB 255, 0, 0

Red255 Green0 Blue0

Accent color.

Tetra Hunter colors are entirely customizable

RGB

RGB 255, 0, 0

Warns you up to 1 km away

Spots unmarked cars too

Ambulances & fire trucks too

Works offline

Watch

Watch it in action.

Plug it in, drive, and hear the beep before the police reach you.

How it works

On the road in 10 minutes.

1
Get the kit
Pick a plan and grab a USB receiver + antenna. Your code arrives by email.
2
Plug in & activate
Plug the receiver into your phone and type your code.
3
Drive
Press Start. A beep means police or an ambulance is near. Eyes stay on the road.

Try it

Green. Orange. Red.

More lights mean a stronger received signal, not an exact distance.

Green — weaker signal
Orange — medium signal
Red — stronger signal

Demo. Real range depends on where you drive.

Green — weaker signal

Received signal strength

Features

What it does for you.

Detects emergency vehicles

Picks up the radio of police and emergency vehicles near you — even unmarked ones.

Screen off? Still on.

Keeps watching with your screen off, so you can use GPS or music.

Just listen

Different beeps for green, orange and red. Eyes stay on the road.

City & Highway

Two modes, one tap. Tuned for town or motorway.

Works offline

No mobile data needed while you drive.

No ads

No ads in the app. No advertising cookies on this site.

vs Target Blu Eye

Compare the complete setup, not just the licence.

Tetra Hunter uses your phone and separately purchased radio equipment. A dedicated detector is a different purchase.

Full comparison

TetraHunterTarget Blu Eye

Price€29.99 – €89.99 + equipmentHardware + installation

InstallPhone + receiver + antennaDepends on model

Switch carsTake your setupDepends on installation

Compare current equipment and installation costs, not just licence prices.

What you need

Your phone + a small USB receiver.

You probably already have the phone. The full kit, lifetime licence included: about €300.

An Android phone

Android 8 or newer. iPhone is not supported.

Already yours

A USB receiver

Get the RTL-SDR Blog V3 (the V4 works too). Two receivers cover the whole band.

V3 or V4

An antenna

A small one inside the car, or a roof antenna for the best range — up to 1,000 m.

Inside or roof

Setup guide

Pricing

Pick your plan

Pay once. No subscription.

6 months

Try it out.

€29.99

One payment · never renews

Police, ambulance & fire alerts
Unmarked cars too
All updates
Starts when you activate

Get 6 months

Recommended

1 year

For daily drivers.

€49.99

One payment · never renews

Police, ambulance & fire alerts
Unmarked cars too
All updates
Starts when you activate

Get 1 year

Lifetime

Pay once. Done forever.

€89.99

Pay once, keep it forever

Police, ambulance & fire alerts
Unmarked cars too
All future updates
Never expires

Get Lifetime

One payment. No subscription. Your plan only starts when you activate it.

FAQ

Questions?

What does TetraHunter do?

It turns your Android phone into a police detector. When a police car (or ambulance, or fire truck) is near, your phone beeps and a bar goes from green to red.

Can I listen to the police?

No. It only notices that a police radio is on nearby. It doesn’t listen to anything.

How far does it reach?

A few streets in town, much further on open roads. A roof antenna gives the best range.

Does it work on iPhone?

No, Android only (Android 8 or newer).

What do I need?

Your Android phone (Android 8 or newer), an RTL-SDR Blog V3 receiver (the V4 works too) and an antenna. The full shopping list is in the setup guide.

How do I get it?

Pick a plan on the pricing page and pay securely with Stripe. You then receive your licence code, your ID and the download link by email.

All questions

Ready to drive?

Hear the beep before you see the lights.

Set up in 10 minutes. Pay once from €29.99.

Get Tetra Hunter Setup guide