Why Your Home Wi-Fi Is Slow Even With NBN Connected

Your new NBN connection is online! Everyone in the house is eager to play games, watch their favourite streaming service or catch up on work using their VPN. You followed the quick setup guide with your new Wi-Fi router and success is imminent! The family retreat to their favourite place of solitude anticipating uninterrupted enjoyment but disappointment sets in… This isn’t what you expected. Why is the new Wi-Fi like our old one? Hoorahs change to confusion and the family start asking what is going on.

Does this sound like you? It’s okay! There are tens of billions of Wi-Fi devices in the world and what you are experiencing has both happened before and been fixed! First, Let’s simplify the complexity of how Wi-Fi works with my favourite analogy:

The conversation analogy:

Your Wi-Fi router/access point is sending and receiving radio waves. The concept is very common: Mobile Phones, TV’s, Radios all send and/or receive data in radio waves, but for this article we will compare Wi-Fi to a group of people having a conversation as conceptually there are many similarities.

Saturday night, a group of friends sitting in the lounge room talking and laughing with background music playing, what a nice evening in. Until…

Should the host prompt conversation?

What happens when more than one person talks at the same time? Conversation can break down with an awkward silence and someone needs to prompt. So, the host realigns or starts a new conversation, and we are back on track. Our analogy is created: If we think of our host as a Wi-Fi Access Point (Router/Modem/etc) whose role it is to improve the efficiency of the conversation. The AP does this by allocating a time and duration for when a client device can communicate. Not very fun, but efficiency has now improved exponentially as every WiFi device has a specific time to participate in the conversation (Send or Receive data).

One of your guests might love the sound of their own voice and jump in whenever there’s a gap. Others prefer to wait politely for their moment. Some have great stories to tell, while others are happy just listening. Now picture the group’s best storyteller holding everyone’s attention: the story is brilliant, but it’s long and needs to be told in a very specific order to make sense. If someone interrupts or talks over them, that part of the story has to be told again before they can continue.

In a wireless network, this exact thing happens all the time. When data doesn’t arrive as expected, it has to be sent again. This is known as a retransmission, and it’s a normal and very frequent; part of how Wi‑Fi works.

More challenges incoming:

There is a 4-year-old child who takes much longer to talk and sometimes interrupts other people talking. Think of this young participant as an old WiFi device that doesn’t support newer Wi-Fi technologies. The older device takes a long time to communicate and slows down the whole conversation.

We’ve all yelled out “It’s time for dinner!!!” to the kids at the other end of the house. They might have heard us, but we didn’t hear their response. The kids yell back, slower, and not nearly as loud as the adults; so even when they’re trying their hardest, their voices don’t carry very far. Wi‑Fi behaves in much the same way. Most Wi‑Fi client devices (phones, laptops, tablets) transmit at significantly lower power than a Wi‑Fi router. This means a device can sometimes hear the router clearly, but struggle to talk back.

Downlink is data travelling from the Wi‑Fi router to your devices like streaming a video, loading a webpage, or receiving a file. Uplink is data travelling from your device back to the router such as acknowledgements, control messages, video calls, cloud backups, and everything that tells the network “yes, I heard that.”

From a network perspective, this often makes the device uplink the limiting factor, influenced by client transmit power, antenna efficiency, and signal‑to‑noise ratio; not the internet connection itself.

Now imagine the kids wandering between rooms while the conversation continues. They can still hear the host, but as they move farther away, replying becomes harder and harder. At some point, another adult nearby could help them communicate better, but only if the kids realise it’s time to switch who they’re talking to. This is essentially what happens with Wi‑Fi roaming.

As a device moves through your home, it continuously decides which access point to talk to. It doesn’t switch the moment signal weakens; instead, it tends to hold on until the connection becomes difficult to maintain, particularly on the uplink. From a networking perspective, roaming decisions are made by the client, based on signal quality, noise, and timing; not because the router decides to “hand over” the connection. This is different from mobile phones on 4G or 5G, where the network decides which tower your phone should talk to as you move around.

Now that the host is yelling everything so the kids can hear and the kids are yelling back, the neighbours can hear the entire conversation as well. Before long, they start talking louder to compensate, which only adds more noise to the room. Even though everyone might be speaking clearly, it becomes harder and harder for any one conversation to stand out.

In Wi‑Fi terms, this is known as co‑channel interference (CCI). It happens when multiple Wi‑Fi networks are talking on the same channel, taking turns but competing for the same shared space. No single network is necessarily doing anything wrong, but performance suffers because everyone has to wait longer to speak. A close relative of this problem is Adjacent Channel Interference (ACI), where nearby overlapping channels cause additional disruption, something we’ll dive into later.

At this point...

It might seem like the obvious solution is to just talk louder? Shout so everyone can hear clearly. Unfortunately, Wi‑Fi doesn’t work that way. When everyone increases their volume at the same time, the room only gets noisier and it becomes harder for any single voice to stand out. In wireless terms, higher transmit power doesn’t create more space; it simply increases the noise floor, forcing every device to wait longer before it can speak.

In many homes, better Wi‑Fi comes not from shouting louder, but from speaking more deliberately. By reducing transmit power and placing access points closer to where devices are actually used, each part of the conversation becomes clearer and more balanced. Devices don’t need to yell to be heard, uplink and downlink stay in sync, and interference is contained to smaller areas instead of spilling into neighbouring rooms and neighbours’ houses. In practice, this often results in fewer interruptions, better roaming behaviour, and more consistent real‑world performance than a single router blasting at full power ever could. Most enterprise Wi-Fi networks are designed with more APs running lower power strategically positioned for where the team members need it.

Next, imagine your teenage daughter in the kitchen with her headphones on and eyes closed, fully committed to her Australia’s Got Talent audition and completely unaware that everyone else was mid‑conversation. Quite rightly, the room falls silent, because that noise overwhelms everything else happening.

Some interference on a Wi‑Fi network works the same way. Certain everyday devices like microwave ovens or DECT cordless phones don’t care about the conversation at all. They simply generate radio waves on the same frequencies that Wi‑Fi use, making it suddenly difficult or impossible for devices to hear each other clearly. Plenty of retransmissions incoming.

From a networking perspective, this non‑Wi‑Fi interference raises the noise floor and reduces usable signal‑to‑noise ratio, leading to dropped packets, retries, and abrupt performance degradation even when signal strength appears normal.

As you can imagine, the four‑year‑old is interrupting, the kids in the bedroom are talking very slowly and sometimes can’t be heard, the neighbours are having a loud conversation next door, your daughter is singing at the top of her lungs, and your friends in the lounge room who came over expecting a great evening are now sitting around looking at each other. That sounds uncomfortably like 2026 at my place… Until I fixed my Wi-Fi Network: What did you think I was talking about?

So how can you actually improve the Wi‑Fi conversation? (You’re on your own with the social side of it…)

Check out my next post, “Why Fast Internet Doesn’t Always Mean Fast Wi‑Fi”