If you run a cotton warehouse outside Lubbock, a tilt-up shop in Odessa, or a 60,000 sq ft distribution building in Midland, you have probably heard the same sentence from a low-bid vendor: "Wi-Fi is weak by the back receiving door. We just need to add another AP." Sometimes that is true. Often it is not. The back wall is rarely the root cause. The usual root cause is a survey that never happened.
This post walks through what an RF survey contains, why it matters before you sign a quote, and what the deliverable should look like.
What a survey is, and what it is not
An RF survey is a measured prediction of how a Wi-Fi network will behave inside a specific building, with a specific set of access points, on specific channels, under realistic client load. It is not a walkthrough with a phone, and it is not a heat map generated from a CAD drawing alone.
A proper survey has two parts.
- A predictive model built from a scaled floor plan, with materials, ceiling heights, rack layouts, and obstacles entered as RF attenuators. This is where most quick-quote vendors stop.
- An on-site validation pass with calibrated tools that checks the model against the real building.
Skip part two and the design is still a guess, just a well-formatted one.
Why warehouses break the omni-AP assumption
Most off-the-shelf APs ship with omnidirectional antennas. Inside a typical office, that is fine. Inside a warehouse, three things change the math.
The first is rack density. Steel pallet racking reflects and blocks 5 GHz signal far more than drywall, and what is on the racks matters too. Once racks are loaded, your coverage map shifts again. A survey done on an empty floor does not predict a stocked floor.
The second is ceiling height. At 30 or 40 ft of clear height, an omni AP spends much of its signal on the space around it and on other APs, and less of it reaches the forklift scanner on the slab. You get loud ceilings and quiet floors.
The third is distance and concrete. Tilt-up walls are thick and dense, and RF that hits them mostly stops there. By the time signal reaches the back wall, it has usually crossed a long run of loaded racking. Adding another omni AP near the back wall without redoing the channel plan can add co-channel interference with the APs you already have.
The fix is rarely more APs. It is the right APs, with directional antennas where they make sense, at the right mounting heights, on a sane channel plan.
What we check on site
When West Texas Wi-Fi runs a survey, the on-site pass covers a short list that does not change. We measure RSSI and SNR at the floor, not at the ceiling. We capture a spectrum sweep to find non-Wi-Fi interference, such as wireless headsets, some forklift chargers, and 5 GHz point-to-point links across the yard. We document materials, rack heights, dock door locations, and any expansion the operator has planned. We check backhaul at the IDF, because a clean RF design over a saturated uplink still drops scans.
We also test the client devices the warehouse actually uses. An older handheld scanner does not roam the same way a current iPad does. If your fleet is mixed, the survey has to account for the weakest client.
What the deliverable looks like
You should expect a written report, not a verbal summary. Ours includes the predictive heat map, the validated heat map, an AP placement plan with mounting heights and antenna types, a channel and power plan, a switch-port and PoE budget, and a bill of materials with manufacturer part numbers.
Ask any vendor to show you a sample survey deliverable in the same format before you sign. If they cannot, you are buying on faith.
Before you sign the next quote
A few questions tend to show whether a quote is built on a survey or a guess.
Ask the vendor what client devices the design was sized for. Ask what channel width was assumed on 5 GHz, and why. Ask to see the on-site validation data, not just the predictive model.
If the answers are vague, ask for the survey before you ask for the price.
Who we are
West Texas Wi-Fi & Networking is a veteran-owned contractor in Lubbock. We design and install commercial Wi-Fi, cameras, access control, and cabling across West Texas, and we hold a Texas Department of Public Safety security license (B31108601) for the camera and access control work. If you want a second set of eyes on your building, book a free site survey or call (806) 370-9434.