Case Studies / Latest Case The WiFi Light Stayed On but the Phones Kept Falling Back to Mobile Data: a Netcomm Router on a Superloop 100M DSL Line (Waterloo)
Student · WaterlooSuperloop 100 MbpsDSL connectionNetcomm routerBrief, repeating dropoutsResolved by router swap
This one had done everything right. A UNSW student starting in T2 pre-booked the activation date on the provider's site about two weeks before moving in, so the line was live on day one. We installed a router that evening and the connection tested normally. The fault that showed up afterwards is the kind people chase for weeks: not an outage, not slow speeds, just a few seconds of nothing at fairly regular intervals — with every indicator light saying the network was fine.
What the student actually reported
The description was unusually precise, which helped. Phones connected to the home WiFi would, at fairly regular intervals, suddenly switch over to mobile data. A few seconds later they would go back to WiFi on their own. Nothing was unplugged, nobody was doing anything unusual, and the router's WiFi light was lit the entire time.
That last detail is what makes this fault so slippery. Almost every troubleshooting habit people have starts with the lights: light off means a problem, light on means the problem is somewhere else. Here the light said everything was fine while the network name itself was briefly vanishing from the air.
The order we worked in
How a few seconds of nothing got pinned on the router
1
Activation date booked about two weeks before move-in
Line live on day one
2
Netcomm router installed and tested that evening
Working normally
3
Student reports phones switching to mobile data at fairly regular intervals
Brief, then recovers
4
Checked the router's WiFi indicator during the fault
Light stayed normal
5
Swapped in a TP-Link router on the same line
No dropouts reported after most of a day
Why the router, and not the line
Everything the fault was not
Superloop service
activated on time
→
DSL wall connection
worked on install night
→
Netcomm router
SSID briefly gone
Where it broke
→
Phones & laptops
fine on the swap router
The plan was active, the wall connection carried a working service on install night, and the same devices behaved perfectly once a different router was in place. That leaves the router itself. What makes this one hard is that the WiFi indicator never stopped showing normal — if the light is lit, the network name should stay visible, and here it briefly did not. That mismatch is what points at a fault inside the router's software rather than at the line.
The single most useful thing on this job was having a second router to put on the same line. Without it, a fault like this is genuinely hard to pin down. You cannot see it happen — by the time you look at the router, the WiFi is back. You cannot prove it to the provider, because from their side the service is up. And you cannot rule the router out by looking at it, because it is reporting itself as healthy.
An A/B swap gets around all of that. Same wall connection, same plan, same phones and laptops, one variable changed. When the behaviour changes with the router and nothing else moved, the answer is the router.
Same line, two routers
Same line, same devices, two routers
| Netcomm (original) | TP-Link (swapped in) |
|---|
| First night | Tested and working | — |
| WiFi indicator | Lit and normal throughout | Lit and normal |
| Network name (SSID) | Briefly disappeared at intervals | Stayed visible |
| What the phones did | Dropped to mobile data, then recovered | Stayed on WiFi |
| After most of a day | Pattern kept repeating | No dropouts reported |
What we would take from this one
- A lit indicator light is not proof. It tells you the router thinks the radio is on. It does not tell you the network name stayed broadcast the whole time, and this case is exactly the gap between those two things.
- If your phone keeps switching to mobile data on its own, that is a real symptom worth reporting, not something to dismiss. Phones do that when the WiFi they are on stops being usable, even for a few seconds.
- Booking the activation date ahead of the move was the right call and it worked — the line was live on day one. The equipment is a separate question from the connection, and this job is a clean example of the line being fine while the box in the room was not.
- On router choice, we would suggest sticking to widely used models. Netcomm is a less common brand here and there is simply less shared experience to draw on when something behaves oddly; a mainstream TP-Link is an easy default, and a higher-end brand makes sense if the budget allows.
Result
The 100 Mbps Superloop DSL service and the wall connection were never the problem. After a TP-Link router was put on the same line in place of the Netcomm, most of a day of normal use went by without the brief dropouts being reported again — the phones stopped falling back to mobile data and the WiFi name stayed visible.