Ceiling or wall: where to mount an access point

Where you put an access point matters as much as which one you buy. The same model can cover a floor beautifully from the middle of the ceiling, or leave half of it dead when it ends up on a wall in the corner, in a closet or above a metal ceiling tile. Here is how mounting changes coverage, and the mistakes that cost the most signal.

Ceiling mounting: the default for a reason

Most enterprise access points are designed to hang from the ceiling. Their internal antennas are omnidirectional in the horizontal plane: seen from above, they radiate roughly evenly in every direction, like ripples around a stone dropped in water. From the ceiling, that energy goes over desks, partitions and people, straight to where the clients are.

• Height: typical installations are between 2.5 and 4 meters. Much higher, and the area right below gets weaker while the signal spreads further than you want.
• Orientation: an AP designed for the ceiling should face down. Mounted upside down or sideways, its pattern no longer matches the room.
• Above the ceiling: hiding an access point above suspended ceiling tiles adds loss, and metal tiles or ducts can block most of the signal. If it must be hidden, use the manufacturer's enclosures designed for it.

Wall mounting: directional by nature

An access point on a wall radiates mostly forward, into the room; the wall behind it absorbs or reflects the rest. That is useful when you want coverage on one side only — a hotel room, a classroom, a warehouse aisle — and harmful when you expect it to cover the area behind the wall.

• Aim it. Point the front of the access point at the area it must cover. In Ondalux Heatmap, set the mounting to Wall and drag the orange handle (or use the dial) to set the direction; the prediction uses a directional pattern with less signal behind the wall.
• Use wall-plate models where they fit. Some access points are built for walls (for example, hospitality wall plates) and are designed for this pattern.
• Do not use a ceiling AP on a wall without checking. Its pattern turns sideways, sending much of the energy into the floor and ceiling.

When a directional antenna makes sense

Directional (patch or sector) antennas concentrate energy in a narrow beam. They are the right tool for very high ceilings, long corridors and warehouse aisles, outdoor areas, and stadium-like spaces where many access points must each serve only their own section. They are rarely needed in ordinary offices.

The mistakes that cost the most

• Access points in the corridor, users in the rooms. It is convenient for cabling, but every room door and wall sits between the access point and its users. Put access points inside the rooms where people work.
• Access points in closets or IT rooms. Cabling is easy; coverage is not. The closet walls and the equipment around the AP take a large share of the signal.
• Behind or near metal. Elevator shafts, metal columns, cable trays, refrigerators and metal cabinets distort and block the pattern.
• All access points on one side of the building. Spread them where the clients are, not where the network cables are.

Try it before you drill

In Ondalux Heatmap, place the access point, switch between Ceiling and Wall, rotate it and watch the coverage and the "requirements met" map change instantly. A few minutes of experimenting on the plan can save a second visit with a ladder.