This was the presentation by AC4HH on the YL Net of Monday November 11
MESH NETWORKS
When you are around a bunch of hams, such as at a Hamfest, you can overhear a variety of topics being discussed - - such as D-Star, DMR, Fusion and MESH. You may have used some or all of these modes, but – like me –don’t really understand how they work. I know they are all digital modes but that is about all. Therefore, I decided to do some research on them for tonight’s lesson.
My sources of information are ARRL’s Operating Manual 12th edition (just off the press) and various internet searches, including Wikipedia.
Digital radios have been around for quite some time. The way digital radio works is that sender’s digital radio transmitter converts his or her voice (analog signal) into digital streams of ones and zeros to be transmitted on a certain frequency. Then at the listener’s radio, the transceiver converts the ones and zeros back into analog signals and we hear the voice.
One of the most recent and exciting developments is hams making their own high-speed digital multimedia (HSMM) networks, called MESH. In simple terms, MESH is hams using amateur radio privileges to operate a private computer network/internet.
Wireless MESH radio networks were originally developed for military applications. Now groups of hams are creating MESH networks with off-the-shelf equipment, perhaps some already lying around in his or her computer room or radio shack to create networks/internets—some of which are very large with wide area coverage. It is a private internet that only licensed hams may use. Anything that can be done on a regular network or internet can be done on MESH.
MESH networks operate on ham frequencies above 50 MHz in compliance with Part 97 of the FCC rules. This means much higher power can be used when needed to establish links between wireless routers, called “Nodes”. Links between nodes can be achieved for miles and miles—limited only by line-of-sight.
In MESH networks every router (node) in the network is aware of every other router (node) and can move network packets through from one unit to another provided there is a link, or chain of linked routers (nodes) between them. Many MESH networks operate across multiple radio bands. Simple modified directional antennas and modest output power can be used for MESH networks. Mounting the router on a mast in a sealed enclosure can reduce losses from long cable runs. A mobile MESH network can run for days from a fully charged car battery or even longer with the addition of a modest solar array or other supplemental power source.
PAUSE
The uses for these networks for amateur radio and public service are endless. Virtually any service that works on the regular internet can be adapted to MESH networks, including video conferencing, instant messaging, voice-over protocol (VolP), sensors and cameras, remote station control and data files. As you can see, the public service and disaster-support utility of amateur radio is expanded tremendously. During a large-scale emergency, it is likely that the normal infrastructure—electrical power, telephones, cell towers, and internet will all fail. That is when amateur radio operators are can provide communications.
After Puerto Rico was ravaged by two hurricanes in the same month—Irma and Marie—in September 2017, MESH networks were invaluable in providing communication for several weeks or even months.
Another example of using a MESH network is in Colin County, Texas. A group of hams there set up HSMM technology to pass information between Texas area hospitals. In Austin, they achieved a 10-mile point to point link across the downtown area, and one more example you can find on the internet is the Santa Barba Amateur Radio Club. They have a huge network called the Amateur Radio Emergency Data network (AREDN).
MESH networks have also been set up locally for use in different events—one was last September for the IRONMAN and one this last Saturday for the Battlefield Marathon.
Much more information about MESH networks can be found by searching on the internet and by going into HSMM.org.
This is the end of the lesson for tonight. I’ll try to answer any questions you have or try to find the answers for you.
This is AC4HH