What Is Transmit Power?
While there’s undoubtedly an entire doctoral program and then some worth of information about radio transmission power and everything that goes along with it to share, in service of getting to the useful day-to-day stuff, we’ll keep it brief here.
The transmit power of your Wi-Fi router is like a volume knob on a stereo. Much like sound energy is measured in decibels (dB), Wi-Fi radio energy is measured similarly with decibel milliwatts (dBm).
If your router allows for transmit power adjustments, you can turn the volume up or down, so to speak, in the configuration panel to increase the power output.
How the transmit power is displayed and adjusted varies between manufacturers. Depending on the manufacturer and model in question, it might be labeled Transmit Power, Transmit Power Control, Tx Power, or some variation thereof.
The adjustment options also vary. Some have a simple low, medium, and high option. Others offer a menu with relative power, allowing you to adjust transmit power anywhere from 0% to 100% power. And others offer an absolute setting corresponding to the milliwatt output of the radio, usually labeled just mW (not dBm,) with whatever range is available for the hardware, such as 0-200 mW.
Turning up the transmit power on your router would seem to be a pretty handy trick, no? However, the relationship between the transmit power of a given Wi-Fi access point and the corresponding user experience isn’t a 1:1 relationship. More power doesn’t automatically mean you get better coverage or speed.
We would go so far as to recommend that unless you are a serious home network enthusiast or professional fine-tuning a network deployment, you leave the settings alone or, in some cases, even turn them down instead of up.
Why You Should Avoid Turning Up Transmit Power
There are certainly fringe cases where tweaking the power on your network gear to increase transmit power can have positive outcomes.
And, if your home is significantly separated from your neighbors by acres (or even miles) of space, then by all means, feel free to play around with the settings as you won’t be helping or hurting anybody but yourself.
But for the majority of people, there are more than a few very practical reasons to leave the router settings as they are.
Your Router Is Powerful; Your Devices Are Not
Wi-Fi is a bidirectional system. Your Wi-Fi router isn’t just blasting out a signal into space to get picked up passively, like a radio listening to a distant radio station. It’s sending out a signal and expecting one back.
Generally speaking, the power level between the Wi-Fi router and the clients the router is communicating with, however, is asymmetric. The router is much more powerful than the device it is paired with unless the other device happens to be another access point with equal power.
This means there will come a point where the client is close enough to the Wi-Fi router to detect the signal but not strong enough to talk back effectively. This is not unlike when you’re using your cellphone in an area with poor coverage, and while your phone says you have at least a bar of signal strength, you’re unable to make a phone call or use the internet. Your phone can “hear” the tower, but it struggles to talk back.
Raising Transmit Power Increases Interference
If your home is close to other homes also using Wi-Fi, be it tightly packed apartments or just a neighborhood with small lots, cranking up the power may offer a small boost for you but at the expense of polluting the airspace all around your home.
Given that increasing the transmit power doesn’t automatically equal a better experience, it’s not really worth decreasing the Wi-Fi quality for all your neighbors just to, theoretically, get a marginal performance increase in your home.
There are much better ways to address your Wi-Fi problems, which we’ll discuss in the next section.
Raising Transmit Power Can Decrease Performance
Counter-intuitively, cranking up the power can actually lead to decreased performance. To use the volume example again, let’s say you wanted to pipe music throughout your entire home.
You could do so by setting up a stereo system with large speakers in a single room and then turning up the volume high enough that you could hear the music in every room. But you’d quickly find the sound was distorted and the listening experience wasn’t uniform. Ideally, you’d want a whole house audio solution with speakers in every room so that you could enjoy the music without distortion.
While broadcasting music and broadcasting a Wi-Fi signal isn’t directly analogous in every way, the general idea translates pretty well. You’ll have a superior experience if your home is blanketed with Wi-Fi from multiple lower power access points than turning the power on a single access point up all the way.
Your Router Likely Adjusts the Power Better
Maybe back in the 2000s and even into the early 2010s, when consumer routers were a little rougher around the edges, you needed to get under the hood and tweak things.
But even back then, and more so now, the firmware on your router can handle adjusting the transmit power on its own. Not only that, but with each new generation of the Wi-Fi standard coupled with updated routers that take advantage of protocol improvements and additions, your router simply does a better job.
On many new routers, especially mesh platforms like the eero and Google Nest Wi-Fi, you won’t even find options for fiddling with transmit power. The system just automatically balances itself in the background.
Increased Transmit Power Decreases Hardware Lifespan
If this one doesn’t concern you, we’re not going to berate you about it because, in the grand scheme of things, it is a minor point compared to the others we’ve discussed—but it’s something to consider.
Heat is the enemy of all electronics, and the cooler devices can run, be it your laptop, your phone, or your router, the happier the chips inside will be. A Wi-Fi access point running in a cool and dry basement is going to last for much longer than a Wi-Fi access point stuck in the top of an unconditioned space in a garage, for instance.
Even though you won’t be able to turn up the transmit power (at least with the stock firmware) past a point that it will outright damage the router, you can turn it up to point that the router runs hot all the time resulting in less reliability and a shortened lifespan.
What to do Instead of Increasing Transmit Power
If you’re thinking about cranking up the transmit power, it’s likely because you’re frustrated with your Wi-Fi performance.
Rather than messing with the transmit power, we’d first encourage you to do some basic Wi-Fi troubleshooting and adjustments.
Consider moving your router and make sure to avoid these common Wi-Fi blocking materials when you reposition it.
And while, sure, tweaking the transmit power can yield better coverage (though it comes with the tradeoffs we outlined above), it’s usually a bit of a band-aid approach.
If you’re fiddling around with an old router to get more life out of it despite the numerous ways using it frustrates you, it’s probably time to upgrade to a new router.
Further, if you have a sprawling home or your home has Wi-Fi hostile architecture (like concrete walls), you might want to consider making that new router a mesh router like the affordable but powerful TP-Link Deco X20. Remember, we want more coverage at lower power levels rather than a single point of coverage operating at the maximum transmit power.
