If you’re deploying Wi-Fi throughout a large outdoor area, such as a municipality, a major consideration is the availability of mounting assets for access points or mesh nodes. In most cases, you’ll need enough mounting assets to support the installation of approximately 25-50 mesh nodes per square mile. Areas with no hills, straight streets, relatively low buildings (two stories or less) and very few trees may get by with 25 (or maybe less) mesh node per square mile, but other areas having hills, tall buildings, etc., may need as many as 50 nodes per square mile.

In populated areas, you can use street light poles and traffic light signals for mounting nodes. Traffic lights often provide the best mounting location because the lights are closer to the center of roads, offering a better orientation for propagating radio signals. Street lights, however, are more widely distributed throughout outdoor areas.

A problem with street lights is that they are often not owned by the municipality. The use of the poles requires coordination with the electric company or other entity, which will usually make the poles available but charge a lease fee of around $5-10 per pole per month. This can add up when covering large municipalities, so be sure to factor in this as a cost.

Another problem with street light poles is that some don’t have a continuous supply of electricity. For example, when the poles are “bank switched,” multiple poles together are turned on at night and off during the day. Thus, a mesh node mounted on this type of pole would only work at night. This is true of most decorative light poles found in parks, downtown streets, and fancier residential areas. If this is the case, then consider running separate electrical wires to the pole (sometimes not practical) or use solar power (may be too expensive) for powering the mesh nodes.

Fortunately, most conventional street lights, though, each have a photo sensor that turns the light on and off. With these poles, which are generally grey with a light at the end of a long arm, the photo sensor is a round object at the top of the light. Power runs continuously to the top of the pole, and mesh node vendors can supply modified photo sensors that include an electrical wire that provides power to the mesh node. You simply replace the existing photo sensor, and connect the power lead to the mesh node. The mesh node will continue to receive electrical power even when the street light turns off during the day.