Bringing Digital Radio to Amateur Radio


Those of us who are Baby Boomers started in electronics before many people knew what digital electronics meant. Electronics meant military communications and radar, TV and radio, and telephones. Carphones and calling internationally were things only the rich or businesses could afford. Computers were expensive, big, and incomprehensible. Our children grew up in a more or less completely digital world, talking around the world essentially for free (10 cents per minute to call Paris, France and 11 cents per minute to call Paris, TX on a wireless phone) and having computers at their fingertips. It has been a struggle with that perspective to interest young people in radio. We may have come full circle now that significant amounts of digital operation involves radio in some form. One of the goals for those of us working on high-speed-multi-media (HSMM) is to provide a means for young people to combine computers and radio as either a hobby or a vocation.


Multiple groups of amateurs in Austin are working together to implement a mesh network of HSMM nodes. Think of this as similar to the D-Star network, but operating at a much higher data rate. The groups in Austin include ARES, Roadrunner Microwave Group, Texas Emergency Management, and Red Cross. There is also a fair amount of work being done in Dallas and Plano. Glenn Currie, KD5MFW, gave a presentation to a standing room only group at the Austin Summerfest this past Saturday, so interest is growing significantly. The group doing the heavy lifting of developing software and hardware has been very busy over the past year.


The original motivation for putting together the mesh node system was to develop a system that amateurs can deploy in a disaster area to provide modern communications capabilities. Operations in the aftermath of Hurricane Katrina and Hurricane Ike indicated that amateurs would need to provide even more than just voice communications. Amateurs are using the mesh concept to build a network where each node has the intelligence to automatically connect with all other compatible nodes that it can "see". The network is self configuring, so you don't need to know more than how to hook a CAT-5 cable from your computer to the HSMM node. WiFi, on the other hand, builds a system that connects two nodes at a time and requires significant understanding of networking to connect wireless access points (nodes) into a working network. The goal in Austin is to create a mesh network that connects all of the local hospitals to the Red Cross and the state emergency management center. Individual amateur stations are also part of the network to provide redundant means of entry and exit from the local network to the outside world just as would occur during a real disaster. One application is creating gateways between the mesh network and the Internet.


A "killer application" and instructions suitable for "ordinary" amateurs were two major pieces missing from the puzzle until recently. It appears that one killer application for HSMM mesh networks may be voice over IP. The group has developed software and hardware that allow a PC and mesh node to implement a private business exchange (PBX) with multiple phone connections. Work is continuing on the PBX applications. A second killer application may come from being able to connect smart phones like Android and iPhone to the mesh network. There was enthusiastic interest from young people at Summerfest for this application. The group has also made significant progressin developing useful instructions for those of us who are barely able to spell "PC". Jim Kinter, K5KTF, has put together a Web site (hsmm-mesh.org) that captures all of the information currently available. It has links to external information on the Linksys routers that are modified to become a HSMM mesh node as well as documentation on how to convert a router to a mesh node. The Website is also the starting point for you to contact the folks working on the hardware and software if you wish to contribute to the effort.


If you understand networking, integrating applications on a PC, and can put that information on paper so others can understand it, your talents are definitely needed. If you have the connections to convince Broadcom that it is a civic benefit to assist with technical information on the BCM5232, your talents are needed.
The Roadrunner Microwave Group has members who are looking at ways to implement long haul circuits to connect geographically separated mesh networks. The goal is to connect mesh networks in all the major metropolitan areas as well as smaller areas such as Kerrville, Bastrop, and Corpus Christi. Ideas for methods are always welcomed. Part of that effort is to identify alternate 802.11 hardware that has technical support from the manufacturer, so we can avoid the problems of not knowing what is really inside the Broadcom IC.


There are any number of activities that will help with the process of turning mesh networks into a robust emergency tool as well as a source of recreational enjoyment. There is a need for software folks to help with the development of the node firmware. There is also a need for folks who understand the PC part of the software equation to help with ideas for new killer applications. One of the most important things you can do is to get a node on the air and start using the system. It's no fun talking to yourself!


It is interesting that the concept of a mesh network is a modern embodiment of the original purpose of the ARRL: it is an Amateur Radio relay network.