QRadioLink is a Linux and Android compatible radio app that can run on smartphones. It can be used to receive and transmit digital radio signals with a compatible SDR such as an RTL-SDR (RX only), or a LimeSDR Mini (TX and RX). The following video by Adrian M shows QRadioLink running on an Android phone with a LimeSDR Mini connected to it. An external battery pack is also connected to maintain power levels over a longer time.
In the video Adrian shows how this combination can be used as a fully portable radio transceiver. The video first shows him receiving broadcast FM, digital amateur radio voice (Codec2 & Opus is supported), narrowband FM and SSB signals. Later in the video he transmits a digital voice signal using the microphone on his Android phone. He notes that an external amplifier would still be needed if you wanted more transmission power.
Over on YouTube user Osama SH has uploaded a video briefly showing the steps needed to use an RTL-SDR dongle to sniff some SMS text messages and voice calls made from his own phone. This can be done if some encryption data is known about the phone sending the messages, so it cannot be used to listen in on any phone – just ones you have access to. In the video he uses Airprobe and Wireshark to initially sniff the data, and find the information needed to decode the text message. Once through the process he is able to recover the SMS message and some voice audio files.
Now a new software package called gr-gsm has been released on GitHub which seems to be a newer and improved version of Airprobe. The gr-gsm software is also much easier to install, uses the newer GNU Radio 3.7 and seems to decode the system data with much less trouble than Airprobe did. We will soon update our tutorial to use gr-gsm, but the instructions on the GitHub are already quite good. The author of gr-gsm also appears to be actively adding new features to the software as well. The video below shows gr-gsm in action.
SDR Touch, the popular Android based software defined radio software for the RTL-SDR has been updated to version 2.0. This new version is a complete rewrite with many optimizations listed below.
100% rewritten from scratch
Improved reception sensitivity and quality
GUI overhaul (Landscape mode, more flexible)
16 bit audio
The author also writes that the rewrite allows for new features coming out in the future such as adjustable bandwidth, FFT size, plugins and a separate GUI for in-car use. SDR Touch is available from the Android Play store.
With its 100 kHz to 1.7 GHz receiving range, the XiOne has a similar tuning range to the standard RTL-SDR dongles when an upconverter or the direct sampling mod is used. What makes the XiOne different is that it will have a built in MIPS processor, an internal rechargeable battery for portability and it will connect directly through WiFi to a smart device. They are also developing SDR GUI software for mobile devices including decoders for things like ADS-B, AIS and NOAA Satellites.
The IndieGoGo backer price for a XiOne is $179 USD, but if you act fast there are 100 units available at the promotional price of $139 USD. At the moment they have a working prototype with completed firmware, portable Java based SDR GUI, iPhone demodulation software, a MacOS ADS-B receiver, an iPad AIS receiver and an iPad spectrum analyzer. The fundraiser is to help them begin serial production.
TD-LTE is a mobile phone standard acronym for Time Division Long Term Evolution. It is one of two variants of LTE technology, with the other being FD-LTE (Frequency Division LTE).
Over in China where TD-LTE is commonly used, Jiao Xianjun discovered that the current LTE-Cell-Scanner Linux program did not support TD-LTE, so he made a fork which does support TD-LTE. LTE-Cell-Scanner is a program which can decode LTE cell tower data which contains information like the cell ID, transmit frequency and transmit strength. With his modified LTE-Cell-Scanner, some MATLAB scripts he wrote and an RTL-SDR, Jiao was able to decode the cell information from 10 TD-LTE signals and 2 FD-LTE signals. He has uploaded a video showing this too.
To use the app, you will need an Android device that supports USB OTG, which most Android devices on Android 4.0+ should support. You will also need a USB OTG cable, and an RTL-SDR dongle. You may want to consider a USB OTG cable that has a second port for external charging capabilities, as the RTL-SDR can drain the battery quickly.
The app is cheaply priced at under $2, so give it a try!
The Android based SDR program SDRTouch has been officially updated to version 1.7. News comes via this forum post. This looks to be a major update which significantly improves audio quality and performance. The new features are listed below.
FM is now in STEREO
New audio recording feature for PRO users
Improved reception and audio quality. All filters were tested for quality and all bugs discovered were removed.
The multi-threading logic was completely rewritten. Now it’s faster than ever before.