Ham radio based TCP/IP network connecting major eastern Washington cities to facilitate emergency communications.
A mailing list has been created for this project: http://groups.google.com/group/hswd
Nodes will be 802.11g access points with OpenWRT linux software. Integrated solutions like the Ubiquiti Networks NanoStation2 will work in areas with strong signal. Higher power devices such as the Bullet2HP and high-gain external antennas may be required in some situations.
OpenWRT linux with the batman-adv kernel module will be used to provide auto-routing networking. Batman-adv operates on TCP/IP layer 2 and acts like a network switch. This architecture allows the use of ethernet protocols like DHCP on top of the mesh network.
Identification requirements will be satisfied with multicast-DNS broadcasts of the node's callsign.
If an internet gateway is added to the network, care will be taken to block encryption and commercial traffic, which are not legal on ham radio.
In this model, both stations are using NanoStation2 APs pointed at each other. Received signal level is calculated to be -65.2 dBm--pretty good!
In this model, the Kamiak node is configured with a 15 dBi vertical omni-directional antenna. This antenna has a vertical beamwidth of about 8 degrees, so the calculated -1.260 degree elevation angle is well within the range of this antenna. The home station is configured with a NanoStation2 (10 dBi panel antenna). Received signal level is calculated as -75.9 dBm--good enough.
For the next model, we'll upgrade the home station to a parabolic dish antenna (19 dBi gain).
Received signal strength has improved to -66.9 dBm.
With an omnidirectional vertical on Kamiak Butte and a 19 dBi dish on a mountain near Spokane, it looks like there's not quite enough signal.
The next model will upgrade Kamiak Butte to a dedicated link to a mountain near Spokane.
4 dBi more on the Kamiak Butte antenna seems to give us just enough gain for a connection at -78.2 dBm.