How to use

Mesh controls radio relaying. Gateway controls the internet link. They are two separate switches.

What mesh does

• Mesh ON: when the node hears a new packet, it retransmits it and lowers the hop counter. A packet it has already seen is ignored.
• Mesh OFF: the node still receives everything and sends its own messages, but it doesn't relay other people's traffic.

Why not just turn it on everywhere?

Every retransmission uses shared airtime on one frequency. When many nodes close together all relay the same packet:

• packets collide and get lost
• the channel gets busy and everyone's messages suffer
• hops are wasted: a packet can only travel about 4 hops, and nearby home nodes burn them for nothing

A few well-placed relays work better than many random ones.

When ON

• High sites (roof, mast, tower, water tank): these form the backbone of the network. Suffixes -21–-24.
• Filling a real coverage gap, deliberately and after checking the map.
• Temporarily: e.g. a car parked on a high point during an event. Turn it off afterwards.

When OFF

• Home nodes in low locations where a relay already covers the area.
• Anything that moves: car, truck, bike, backpack, handheld. Suffixes -25, -27, -28, -29.

A personal device is a client, not a relay.

Before turning mesh on, check the map (meshmap.oevsv.at). If a relay already covers your area, leave mesh off.

What it is

A gateway is a node with an internet connection (Wi-Fi or Ethernet) that links our local radio network to the MeshCom server. Through it, messages from Chicagoland reach the rest of the MeshCom world, and the other way round. Suffix -20.

Where to put one

• On a node with a reliable internet link and good radio coverage, ideally high or central.
• The first node in a new area (on a roof, mesh ON) should also be a gateway. That gives everyone around it access to the full network from day one.

How many

One per area, at most two. Two give redundancy, and more is too many.

Too many gateways cause:

• duplicate packets reaching the server by several paths
• extra load on the server and the radio channel
• harder troubleshooting
• nearby nodes talking to each other through the internet instead of over radio, which defeats the point of an off-grid network

Planning a gateway? Contact us first at info@group312chicago.org so we can keep the count right.

Basic setup

--setssid YourWiFi
--setpwd YourWiFiPassword
--gateway on

Full command list: MeshCom commands (ICSSW)

Source and more detail: meshcom.pl