Why survey first
A mesh network is only as good as its lines of sight. Radios at 5 GHz and above need a clear path between antennas, and a single tree, water tank or new extension can turn a strong link into a weak one. A survey finds those paths before anyone buys a radio or climbs a roof.
A good survey also finds the people: the building owners who might say yes, the institutions with tall roofs and the neighbors who already know which landlord answers the phone.
What to bring
- A printed grid map of the area, lettered across and numbered down, matching the grid used on this site.
- Binoculars and a phone with a compass and an inclinometer app.
- A clipboard with survey sheets. Record grid squares and building types, never addresses or residents’ names.
- A laptop or tablet with a spectrum scanner, for a noise-floor reading at each candidate hub site.
- High-visibility vests, water and the steward on call’s number.
The survey walk
- Start from the tallest buildings in or near the area: libraries, churches, schools, housing cooperatives, public housing towers. These are hub candidates.
- From the street, look up at each candidate and note which way its roof faces, what is on it already and whether there is a parapet to mount on.
- Walk the blocks around each candidate in a widening spiral. For every building, note whether its roof could see the candidate: clear, partly blocked or blocked.
- Mark trees in leaf. A path that is clear in February may be blocked in June; survey in summer if you can, or allow for it if you cannot.
- Where you have permission, go up. Ten minutes on a roof with binoculars tells you more than an hour on the street.
Choosing hub sites
A good hub site sees at least forty roofs within about 400 meters, sees at least one other hub site, has power available and has an owner who will sign a written agreement. Institutions are usually easier than private landlords: they answer to a board, they plan years ahead and they are often glad to be asked.
Aim for more hub sites than you need. Agreements fall through, roofs get replaced and boards change their minds. The surveys behind most LoTek networks list two or three candidates for every hub that was eventually built.
Noise and interference
At each hub candidate, take a five-minute spectrum scan across the 5 GHz band and note the busiest channels. Dense neighborhoods are full of home Wi-Fi, and the backbone should avoid the worst of it. The spectrum basics playbook explains which channels are available and what radar avoidance means for your choice.
Writing it up
A survey ends with a short report for the network’s founding assembly: the proposed hub sites, the roofs each could serve, the backbone paths between them and a rough count of nodes. Keep the working sheets with the stewards. Publish only grid squares and building types, the same way this site does.