Warehouse wireless is its own discipline. An AP layout that works beautifully in an office will fail in a distribution center, and the failure is always in the same places.
Inventory is the obstruction
An empty warehouse and a full one are different RF environments. Racking loaded with liquid, metal, or dense product absorbs and reflects signal in ways an empty-building survey will never show you.
If your coverage got worse and nothing changed in IT, ask what changed in the racking.
Ceiling-mounted APs are usually wrong
In a 32-foot ceiling, an omnidirectional AP mounted at the deck sprays most of its energy where nobody is standing. The devices are at floor level, in aisles, between walls of product.
Directional and patch antennas aimed down the aisles almost always outperform more omni APs at the deck.
Coverage is not the same as capacity
A scanner shows full bars and still times out. That is capacity, not coverage — too many devices on one AP, or a client stuck on a distant AP it should have roamed off.
Roaming is where handhelds break
Forklift-mounted and handheld scanners roam constantly. If the cells overlap too little, the device holds a dying connection too long. If the power is set too high everywhere, the device never has a reason to move. Both look identical to the user: it just stops working at the same spot every day.
The 2.4 GHz problem
Older scanners are 2.4 GHz only, and 2.4 GHz has three usable channels. In a large building you will reuse them. Plan the reuse pattern deliberately or the APs will interfere with each other.
What actually fixes it
- Survey the building loaded, not empty, and walk the aisles at device height.
- Design around the devices you have, including the oldest scanner still in service.
- Mount and aim for the aisles, not for the ceiling tile.
- Turn power down so clients roam instead of clinging.
- Cable it properly. Cat6A to every AP. The uplink should never be the ceiling.
- Re-survey after big racking changes.
If you are chasing the same three aisles every month, a half-day survey will tell you more than another year of adding access points.