Broadband-Hamnet MESH Network for Emergency VOiP Communications





I recently saw an advertisement on Facebook for a new upcoming release of a device called Beartooth. Beartooth is a handheld device that works with your smartphone to keep you connected when there is no cell service. Basically, it creates a mobile mesh network with other bear tooth nodes in the vicinity for off-grid communications. The ad-hoc mesh network idea really caught my attention as I had already been wondering what we would do with all of our digital communications if the internet went down. Obviously, things like DMR, DStar, Fusion, and Allstarlink would be dead in the water.




What is a mesh network?





So I started doing some research on mesh networking and was surprised to discover that the amateur radio community has been dabbling in mesh technology for several years. One of the main websites for this technology is broadband-hamnet.org. This website plus many youtube videos on the subject spurred me on to experiment with mesh network for emergency communication in a grid-down situation.


‚ÄčBelow is more information on mesh networking.



Broadband-Hamnet Mesh Networking





The amateur radio community has written complete new firmware to replace the OEM firmware that comes with select wifi routers. See the list of supported hardware that can be found on the embedded website below. The process of upgrading to the new software is also explained in detail on their website and after doing this many times now, I can tell you it is a very simple process.




Creating a FreePBX VOiP Service on a Broadband-Hamnet Mesh Network





The plan I have for my mesh network is to provide a digital form of emergency communication for my local community here in the Ozarks of Northwest Arkansas. I decided to add a FreePBX phone service to my network so we could have a reliable means of communicating with neighbors in a grid-down situation caused by things like ice-storms or tornados. The hardware we have now settled in on for each node is the Linksys 54GL router with firmware upgrade and a Grandstream 1610 Sip phone. The total cost per each node is less than $80.00. However, on my end, I have the added expense of the hardware for the PBX server which is a Raspberry Pi3 as seen in the photo above. It's the little black box with the red light sitting on top of the router.




Each Mesh Node is an Extension on the FreePBX Service





So far, anyone who I can visibly see in my community I can get a successful connection to with our wireless network. I use the airLink Outdoor Wireless Link Calculator to get added information about distance and terrain as seen below. The main node in the network is at my home location and it is a TP-Link 2.4GHz 12db gain omni-directional antenna at about 25 feet to ensure that the signals are strong enough to handle the VOiP data. Without this link the system wouldn't work. It would be best if everyone on the system had this setup but the added expense of the antenna, the Bullet, the POE (power-over-ethernet) module and cat cable would be a considerable deterrent to others buying into the program. As it is, with the single antenna and node (my expense of about $150), the routers themselves communicate just fine at these distances as long as the router is on the side of the house facing my location. In one case we had to put an additional router outside on the porch facing my location and the other node inside the house connected to the SIP phone.




The Broadband-Hamnet Interface Showing All Connected Mesh Nodes





The neat thing about the Broadband-Hamnet firmware is that it allows you to see all the connected nodes to the mesh network and what can be seen from each individual node with the LinkQuality information and the services provided at each node. In this case, the only service is the FreePBX service being provided by my node seen as raspbx. What the display shows below is all the nodes/extensions as seen by the main access point.



In summary...





Creating this Broadband-Hamnet Mesh Network is accomplishing more than just a backup emergency communication system for grid-down situations. It is also presenting a good amateur radio image to the community and bringing the community together as they become more aware of their need for one another in emergencies and general assistance. I am very glad that I embarked on this new technical challenge and adventure and especially pleased the positive response by most of my neighbors who think it is very worthwhile and help to spread the word. It may not work in every community but it sure works well here in the Ozark mountains of Arkansas.