The technology behind Outernet consists of the following components: signalantennaSDR, amplifier, and free software. Learn about this technology and hardware in greater depth.


Our signal is broadcast over three Inmarsat satellites, offering coverage on continents and on the open seas. These three birds are:

  • I-4 F1 APAC (Asia-Pacific), at 144-degrees East
  • Alphasat, at 25-degrees East
  • I-4 F3 Americas, at 98-degrees West

Our frequencies are:

  • APAC: 1545.9525 MHz
  • Alphasat: 1545.94 MHz
  • Americas: 1539.8725 MHz

Bitrate is about 2kbps, or 20MB of content per day. 

Outernet L-Band hardware can also be used for Inmarsat reception, including SafetyNET, EGC, and AERO.



Outernet uses a portable L-Band patch antenna. This directional antenna has a beam width of 40 degrees, so pointing is easy. Just aim in the general direction of the satellite. 

This antenna is housed inside Lantern, but if you are more of a do-it-yourselfer, you may buy an antenna to build your own receiver.


  • 1525 - 1559 MHz
  • 8dbi
  • 4 inch SMA Male connector
  • 12cm x 12cm x 1.5cm, 3.5 oz

radio & Amplifier

You may buy the amplifier and SDR (Software Defined Radio) together or individually. 

Amplifier Specifications:

  • Frequency: 1525-1559MHz
  • Center Frequency: 1542MHz
  • Gain: 34 dB
  • Voltage: 3.0V - 5.5V
  • Current Draw: 25 mA
  • Dimensions: 6.5cm x 1.5cm x 2.5cm

SDR Specifications:

  • Ultra-low phase noise 0.5PPM TCXO
  • RF-suitable voltage regulator
  • Custom heatsink
  • SMA female connector
  • SDR frequency range of approximately 25MHz-1700MHz
  • Bias tee enabled
  • Brushed aluminum body, 8.5 x 1.3 x 1.7 cm

SDR (top) and Amplifier (bottom).

Librarian Interface, viewed from a smartphone.

Librarian Interface, viewed from a smartphone.


Outernet software is called rxOS, which runs on C.H.I.P.. The image includes:

  • Demodulator
  • Decoder
  • rxOS Firmware (see in our Git Hub repository
  • Librarian, Outernet's user interface and content management software.

Use any device to connect to the receiver's WiFi and use any web browser to navigate to Librarian.