Airspy Now Available for Pre-Order (Shipping Mid November)

The long awaited Airspy software defined radio is now available for preorder and will ship during mid November for those orders placed before November 7. It is priced at $199 USD.

The Airspy is an RX only SDR with a tuning range of 24 MHz to 1.7 GHz, up to 10 MHz of instantaneous bandwidth and a 12-bit ADC. The full list of features is shown below. If you are looking for an upgrade to the RTL-SDR and do not need TX capabilities, this is probably the SDR that will provide the best performance for price.

  • Continuous 24 – 1750 MHz RX range with no gaps
  • 3.5 dB NF between 42 and 1002 MHz
  • Tracking RF filters
  • 35dBm IIP3 RF front end
  • 12bit ADC @ 20 MSPS (80dB Dynamic Range, 64dB SNR, 10.4 ENOB) – Yeah, size does matter.
  • Up to 80 MSPS for custom applications
  • Cortex M4F @ up to 204MHz with Multi Core support (dual M0)
  • 1.5 ppm high precision, low phase noise clock
  • 1 RTC clock (for packet time-stamping)
  • External clock input (10 MHz to 100 MHz via MCX connector) – Ideal for phase coherent radios
  • 10 MHz panoramic spectrum view with 9MHz alias/image free
  • IQ or Real, 16bit fixed or 32bit float output streams
  • No IQ imbalance, DC offset or 1/F noise at the center of the spectrum that plagues all the other SDRs
  • Extension ports: 16 x SGPIO
  • 1 x RF Input (SMA)
  • 1 x RF Output (Loopthrough, U-FL)
  • 2 x High Speed ADC inputs (up to 80 MSPS, U-FL)
  • 4.5v software switched Bias-Tee to power LNA’s and up/down-converters

See our big comparison list of other SDRs here.

Airspy Software Defined Radio
Airspy Software Defined Radio

New Raspberry Pi Image with RTL-SDR Drivers and GNU Radio Built In

A new image for the Raspberry Pi containing RTL-SDR software has been made available by tech enthusiast Gareth Hayes. The image contains all the software and drivers needed to get started with the RTL-SDR or HackRF on a 512MB Raspberry Pi. It is very useful as compilation of large software like GNU Radio is slow and problematic on an embedded PC like the Raspberry Pi. The image contains the following software:

  • GNU Radio V3.7.5 built from source, including GNU Radio Companion
  • Osmocom GNU Radio Source (and Sink) Blocks
  • Support for DVB-T USB dongles
  • Support for HackRF One (and Jawbreaker)
  • RTL-SDR Suite
  • Gqrx

A few months ago we also featured a similar image for the BeagleBone Black.

Raspberry Pi Mini Linux Computer
Raspberry Pi Mini Linux Computer

Shielding the RTL-SDR

Over on Reddit user will1384 has posted about his imgur photo album that clearly documents some well researched steps that he took in an effort to shield the RTL-SDR dongle from interference. Interference is caused by strong out of band signals that can sometimes show up even when no antenna is connected to the dongle. Shielding the dongle helps to remove this interference.

The main steps he took were the following:

  1. Buy an aluminium case from ebay and put the dongle inside it.
  2. Remove the USB connector and ground the dongle ground to the aluminium casing using a 1M Ohm resistor and a 47nf ceramic disk capacitor.
  3. Connect the USB data lines to a USB extension cable and wrap a toroid around the 5v and GND lines and twist the two data lines together.

There is a discussion about this shielding project on Reddit.

Shielding Wiring Diagram
Shielding Wiring Diagram

Receiving Hellschreiber with the RTL-SDR and an Upconverter

Over on YouTube user BSoD Badgers has uploaded a video showing reception of Hellschreiber on HF at 20m. To receive the HF frequencies he used a ham-it-up upconverter. He used SDR# to receive the signal and the Fldigi decoding software to decode the signal.

Hellschreiber is a fax-like communications mode used by amateur radio hobbyists.

Hellschreiber 20M

RF Analyzer Android App for the HackRF

Earlier this month we posted about a new port of the HackRF software defined radio Linux library for Android. Now the author of the Android port has created a new app called RF Analyzer. The app is basically a real time spectrum viewer that includes a waterfall display. The app can be downloaded from Github at

The app currently supports the following features.

  • Browse the spectrum by scrolling horizontally
  • Zoom in and out, both horizontally and vertically
  • Adjust the sample rate and center frequency to match the current view of the screen by double tapping
  • Auto scale the vertical axis
  • Jump directly to a frequency
  • Adjust the gain settings of the HackRF
  • Select a pre-recorded file as source instead of a real HackRF
  • Change the FFT size
  • Setting the frame rate either to a fixed value or to automatic control
  • Activate logging and showing the log file

In the future the author intends to support the RTL-SDR and implement demodulation for basic modes such as AM, FM and SSB.

To use the app you’ll need an USB OTG (on-the-go) cable to connect your Android device to the HackRF.

RF Analyzer Android App for the HackRF
RF Analyzer Android App for the HackRF
RF Analyzer demonstration – Showing a FFT plot by using an Android device and the HackRF

Tutorial Video Showing How to Receive Meteor M2 Weather Satellite Images with the RTL-SDR

Recently we posted about a tutorial showing how to receive LRPT weather satellite images from the new Russian Meteor M2 satellite. Now over on YouTube user Tom Mladenov has uploaded a tutorial video showing all the tutorial steps.

The reception process is to essentially record an IQ file of an LRPT transmission using SDR#, reduce the sample rate of the IQ file using audacity and then decode the file using LRPTrx.exe. Then finally the decoded data can be imported into LRPTofflineDecoder to produce an image.

How to receive Meteor M2 weather satellite with RTL SDR

Using the HackRF on Android

Micheal Ossmann’s HackRF Linux library has recently been ported to Android by programmer Dennis Mantz. Dennis has also made a blog post showing how to use the library. In addition he’s uploaded a YouTube video showing off the library using an example app. The app is capable of recording an RF signal and replaying it via the HackRF’s TX capabilities. In the video Dennis shows the example app recording a broadcast FM station and then retransmitting the recording to his car radio.

Using the HackRF on an Android Device

University Lab Sheet Explaining RTL-SDR and Demodulation Theory

A reader of our blog has recently written in to let us know about a lab sheet from the University of Colorado College of Engineering and Applied Science which clearly explains software defined radio theory with the aide of an RTL-SDR dongle.

The lab sheet starts off by showing how the RTL-SDR works at a high level, then goes on to explain the function of the R820T tuner chip and RTL2832U chip. The lab then shows a behavioural level model of the RTL-SDR which becomes useful for mathematical analysis. Finally, the lab also explains demodulation theory for FM and FSK signals and sets several lab exercises that involve writing FM and FSK demodulators in MATLAB or Python.

The zip files mentioned in the lab sheet can be downloaded from

RTL-SDR Behavioural Model
RTL-SDR Behavioural Model

Another TCXO RTL-SDR for Sale And Aluminium Cases

Recently we posted about a new US based source for modded TCXO RTL-SDR dongles. Now Nooelec, one of the most popular sellers of standard RTL-SDR dongles have started selling their own version of TCXO modded dongles as well. Their dongles come with a 0.5 ppm TCXO oscillator as well as an external aluminium casing for interference shielding.

A TCXO is a temperature controlled oscillator. Its advantage over a standard oscillator like the one used in a normal RTL-SDR is that its frequency will not drift as the temperature of the dongle changes.

Nooelec are also selling the aluminium casing by itself in silver and in blue for use in shielding dongles that you already have.

Nooelec TCXO Dongle
Nooelec TCXO Dongle

Hak5: Mobile SDR Apps

On this episode of Hak5, a popular YouTube technology channel, Shannon shows two Android based ADS-B RTL-SDR apps that we have mentioned on this blog previously. One is “ADS-B on USB SDR RTL” and the other is Avare ADS-B. Both are ADS-B apps that will display real time airplane positions on a map.

To run these apps you need a RTL-SDR dongle, a USB OTG cable and an Android phone.

Cellular Testing Tools and Mobile SDR Apps, Hak5 1708