How to use RTL-SDR on Android
To use SDRTouch, first ensure you have downloaded and installed both the SDRTouch and the RTL-SDR Android Driver application. When you plug in your RTL-SDR adapter into your Android device with a compatible USB OTG cable, you should see the adapter’s blue LED turn on. If not, try another cable or ensure your device is compatible.
Note: If you’ve installed Avare ADSB you may notice the program try to automatically launch when it detects your RTL-SDR adapter. Just close the prompt by pressing the back key on your device so that it doesn’t launch. If it does launch, close the application to ensure it doesn’t interact with SDRTouch.
Next, load up SDRTouch and press the power symbol on the top left of the application. When you press the power button, you should receive a prompt from the RTL-SDR Android Driver, asking if you want to use it. Press yes and SDRTouch should immediately activate.
Once SDRTouch is activated, you should immediately see something called the spectrum analyzer and waterfall appear. The spectrum analyzer is on the top half of the screen, showing radio activity at the frequencies you’re viewing. The waterfall appears below on a sliding graph, showing historically the activity on a radio frequency. If you’re using the demo version, these won’t appear and make it much more difficult to see radio activity from your device.
To test and see how well your RTL-SDR device is working, first try tuning to a local radio station, which in most areas run between 88MHz and 108MHz. Since local radio stations usually have great signal strength, it’s an easy way to practice finding stations and see how good your antenna is. With SDRTouch you can drag along the top of the screen to search for channels, as well as use the “Jump” key to jump to a particular frequency.
If you want to tune into local law enforcement, fire departments, or other frequencies, it’s best to use a database website such as RadioReference to find out what frequencies they operate on. Be sure to also see if the frequencies you want run on FM, AM, or other frequency modulations. You can adjust the signal type by pressing the icon next to the power button, which will by default say FM as this is the default modulation for SDRTouch. You’ll want to switch to AM if you, for example, want to tune into local airports to listen to airplane chatter. The signal types you’ll care most about are FM and AM, as this is where most voice communication takes place that you can listen to with SDRTouch. It’s important to note that with SDRTouch on Android you cannot do complex things such as trunking, so some law enforcement radio signals may be difficult to listen into.
Another important button to use on SDRTouch is “Squelch.” As you probably have noticed, radios pickup a lot of background noise that sounds more or less unpleasant. Squelch picks up this sound and sets a minimum volume so that you can filter out the background noise. If you pickup a strong radio signal, it will deactivate the squelch and let you listen in.
You’ll also want to understand that not all radio signals will be intelligible. Decoding data signals and other information will require the use of a computer. You can use this guide for help with understanding the types of signals you can pick up with SDRTouch. Also bear in mind that electrical equipment, power lines, and solar activity affect radio equipment and can create signals that you may pickup on your device. SDRTouch also comes with a host of other features, including the ability to record, scan channels, and bookmark channels. Play around with the software and see what radio signals you can discover! Most RTL-SDR devices can pickup signals between 25MHz and 1750MHz, giving you plenty of room to explore.
How to track aircraft with ADSB
If you’re looking for another experiment to try with RTL-SDR on your Android device, then go ahead and launch Avare ADSB. ADSB is the communication standard used by aircraft to tell pilots where other aircraft are in the sky, but you can still pick it up from the ground with a good antenna or live near an airport. The program should prompt to open when you plug in your RTL-SDR device. Go ahead and launch the application, and you should see a screen that states it is “receiving packages.” If you do not see this message, or “Failed to open device,” Then try restarting Avare ADSB or unplugging and plugging back in your RTL-SDR adapter. This should get the program running.
Once it’s running, you should see an option for Data and Map buttons on the screen. The Data panel lists all the planes in your area that the device detects along with their longitude and latitude. If you have an internet connection, then click Map to open a Google Maps overlay with this information. You should get a detailed map of each plane your antenna can detect. The information updates every few seconds, letting you watch as planes enter and exit nearby airspace. This is mostly just a fun way to visualize what RTL-SDR can do with data information over radio, and is one of many things you can do with RTL-SDR.
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- What is SDR and is it legal?
- What equipment and software do I need?
- How to use RTL-SDR on Android
- What else can I do with RTL-SDR?