A wireless link that works one minute and drops the next is one of the most common — and most misdiagnosed — RF problems. The cause nearly always falls into one of two camps: something on the air is interfering with it, or something in the installation is quietly limiting it. Telling them apart is the whole job.
First, what "dropping out" usually means
Before chasing causes, it helps to notice the pattern. Does it drop at the same time of day? Only when certain machinery runs? Only in one area? Or does it fade with distance and obstruction? Intermittent faults that follow a schedule point towards interference; faults that track distance and walls point towards the install. A few notes on when it happens will save hours later.
Camp one: something on the air
Most wireless lives in shared, unlicensed spectrum, so it competes with everything else nearby. Common interferers include:
- Congestion — too many networks or devices on the same or overlapping channels, so airtime runs out and packets retry until they fail.
- Non-Wi-Fi emitters in the 2.4 GHz band — older video senders, some cordless systems, certain industrial equipment and the occasional leaky microwave oven.
- Broadband electrical noise from variable-frequency drives, switch-mode power supplies, LED drivers and motors, which raises the noise floor so the receiver can no longer hear a clean signal.
- Receiver desense — a strong transmitter close by (even on a different band) overloading the front end so it goes briefly deaf.
The tell-tale sign of this camp is that the link is fine until "something" happens — a shift starts, a machine cycles, a neighbour's system wakes up.
Camp two: something in the install
The other half of dropouts have nothing to do with interference at all:
- Antenna and cabling — a poor connector, a kinked or wrong-impedance cable, water ingress, or simply an antenna pointed the wrong way.
- Siting and obstruction — a link that just clears a wall on a good day and doesn't on a bad one, or a fresnel zone clipped by racking, vehicles or stock that moves.
- Marginal link budget — the system was always running on the edge, so any small loss tips it over.
- Multipath — reflections in a metal-rich environment arriving out of phase and cancelling the wanted signal in specific spots.
The tell-tale here is that the problem tracks where and how far, not when.
How an RF engineer pins it down
This is where guessing gets expensive. Swapping access points or radios blindly often just moves the symptom around. A proper diagnosis uses a spectrum analyser to see what's actually on the band — the noise floor, who's using the airtime, and whether there's an interferer that shouldn't be there. If there is, direction finding traces it back to source. If the air is clean, attention turns to the antenna system, link budget and siting instead. Either way you end up with evidence, not a hunch.
Two safe things you can try first
Note exactly when the dropouts happen and what else is running at the time — that single observation often points straight at the cause. And check the obvious physical layer: connectors tight, cable undamaged, antenna where it should be. Beyond that, resist swapping kit blind — it usually buries the evidence.
See wireless diagnostics →When to get someone on site
If the dropouts are costing you throughput, if your IT or networking provider has looked and found nothing, or if the link is mission-critical and you simply can't have it failing, that's the point to bring in RF test gear. Network tools see the network layer; a physical-layer interference source is invisible to them and exactly what a spectrum survey is built to catch.