Category Archives: Uncategorised

Touchscreen for my Raspberry Pi

Finally found a use for the latest in a collection of Pi’s – grabbed a 7″ touchscreen for the Pi 3 from Element14 and connected it up in a few minutes.

Here is the rear view with the Pi attached above the LCD controller.

The screen actually behaved and looked better than I thought it would.

The only drawback is the rather cruddy virtual keyboard – I am sure that someone will eventually improve on the UI of the only option that so far I am aware of,  and is referenced on the official site.

Anyhow, the use I have in mind is an RF direction finder.

I recently participated the @sdr_melbourne foxhunt located in the Westgate Park. Most of our targets were in the 433 MHz ISM band and I had built a small portable three element yagi for the DF role. I designed it for maximum back to front ratio, and minimal side lobe radiation, both desirable characteristics for direction finding.

To be continued …


Putting radiation into perspective

Radiation levels are not well understood by the general public. I am amazed at the levels of ignorance and misinformation surrounding radiation, it’s sources and what is safe and what isn’t.

This excellent chart courtesy of the XCKD team helps educate and enlighten. Please have a look at it and know what may be harmful for you and what isn’t. You will be surprised!


Outernet provides a free service with global reach designed to enable low cost connectivity to communities that would otherwise be out of touch.

This post is almost completely sourced from the Outernet web site. My Outernet kit just arrived and these are the components:

Outernet kit contents

Go to their site or read on here to see how it work and what is involved.

Our filecast differentiates itself from a traditional broadcast by sending information as data files, so content is no longer limited to video and audio. Now, any content format can be sent over a radio signal. Receivers automatically cache these files locally, so users can enjoy flexible, on-demand access to content.

With the global reach of satellite broadcasting, this system is paving a new way to distribute, access, and consume content.

Read on to learn more about filecasting, the Filecast Center, or applications of technology. Visit our product page to learn more about our receivers.



A file is converted into a radio signal and transmitted around the world over satellites.

This process is similar to what happens with satellite radio, but the file can be in any format.

Read more about the signal.



The receiver catches the radio signal and extracts the original file.

Once extracted, the files are automatically saved on the receiver’s internal drive.

Read more about the hardware.


The receiver acts like a local server for the saved content, and emits a WiFi hotspot.

Users can connect to this WiFi with any device to access the saved content.

Read more about the user interface.


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.