Wednesday, February 26, 2014

Vodafone mobile network in a back pack - "Go Kits" for restoring communications

From Engadget - Vodafone's network in a backpack connects people after natural disasters:

This story has a couple of interesting points to Amateur Radio people who have been building go kits to provide communications when there is no infrastructure for several decages now.

This mobile phone carrier has two types of Go kits (one 220 lbs, and now a 24 lb backpack) that they can deploy to disaster areas to provide communications services.

The backpack has "2G GSM connection capable of handling thousands of text messages and five calls made at once to people within a 328-foot radius. It's equipped with a GSM base transceiver that uses satellite connection to link up to a host network."

(Note: Thousands of text messages vs. 5 simultaneous voice calls.  So it's important to educate people that text messaging has a much better chance of getting through during times of network issues whether it's congestion or outages.  People will eventually figure this out, but may loose valuable time and/or battery power.)

Details on larger version:  "In fact, during Vodafone's mission to the Philippines following Typhoon Haiyan, two 220-pound kits handled a total of 1.4 million text messages and 443,288 calls within 29 days. Obviously, the larger machine has a wider operating radius (3 miles), but the Mini has its own set of pros. Since it can be deployed within minutes and be carried on planes, it can potentially help more people -- and more quickly, too."

This implies that the 220 lb kit can't be carried on a plane, which sounds like a serious limiting factor for deployment. Possibly it's just due to the reporting in the story. 220 lbs is not a problem weight wise. So perhaps actual size, batteries, or the inclusion of generator keeps it from going on planes.

Tuesday, February 18, 2014

"encyclopedia" of digital modes (modulation/encoding)

This looks like it could be very useful for those interested in decoding or understanding various digital modes, how they are encoded/modulated.

The web site is:

There are print books for sale for HF modes and another for VHF/UHF. Roland Proesch is the author. (The books are available in german and english)

For each book a PDF except is available for free that still has lots of helpful information in it.

In addition to a brief description for each signal are a number of pictures of oscilloscope and sonogram/waterfall type views.

RTL-SDR users would find the VHF/UHF book directly relevant. However the HF book looks like it might provide a better foundation.

Take a look at
  • HF: (81 pages) -
  • VHF/UHF: (56 pages) -
Unfortunately, it doesn't look like he's selling the complete books in electronic form, only print. I came across this from a post to the digitalradio yahoo group by Ian Wade, G3NRW.

I've also forwarded this to which I find is a very useful blog for SDR and digital modes.