DEV Community

The REAL difference between 5GHz or 2.4GHz WiFi

Ben Halpern on September 17, 2021

This post comes from some interesting tweets I saw, and really speaks to how difficult it can be to get the right amount of "correctness" when you ...

Read full post

Kasey Speakman • Sep 17 '21

I would like to answer with the conventional wisdom I've heard and anecdotes from my experience. However, it seems like a fact-checkable engineer's explanation would be best here. Kindof a commentary on the value of freely available information. 🙃

Austin S. Hemmelgarn • Sep 19 '21

Strictly speaking, in a vacuum, there is no difference in propagation range between 2.4GHz and 5GHz with all other factors being equal. All that matters is initial energy.

However, that’s not very useful in practice for two reasons:

The way that 2.4GHz and 5GHz interact with solid objects is different. Depending on the material, the likelihood of reflection versus absorption versus transmission actually does vary with respect to frequency. 2.4 GHz tends to reflect off of or propagate through most common building materials, while 5 GHz tends to be absorbed more readily. This leads to a lower effective range for 5GHz in most settings.
The usable channels for 5 GHz have different allowed transmit power limits, and APs which auto-select ‘open’ channels tend to be more likely to select those channels which have lower transmit power limits because they will by definition have less activity. For example, in the US, 36-50 and 149-165 have a 1W max transmit power, while the others are capped at 0.25W.

These two factors combined mean that in the traditional setup of a single AP for a house or business, 5 GHz really does have less effective range. It’s not a ‘myth’, it’s just not some inherent aspect of ‘’5 GHz’ like everyone seems to imply.

Overall though, this is part of why ESS setups (sometimes (not always accurately) called ‘mesh’ setups in consumer marketing material) are so useful, and the limitations of 5 GHz are what is pushing their adoption in consumer settings.

David Dutton • Dec 17

That's why I replaced the antennas on my access points to double their max wattage power.

Karan Gandhi • Sep 18 '21

Real world.Depends on the WiFi reciever & walls, I guess. ¯_(ツ)_/¯

The range of 5G is better on my Intel WiFi Card & one Xiaomi phone(SD 845).
The range of 2.4G is better on the Realme, other Xiaomi devices, Nokia , Laptop and older USB Wifi.

J3ffJessie • Sep 18 '21

As a technician who installs internet services the above assertions are true. 2.4ghz frequency travels further and has better penetration due to the lower frequency. 5ghz will provide faster speeds at a shorter distance. Most modems now are equipped to automatically divert traffic to the most optimal frequency.

There are some that don’t, which will cause issues with certain devices like printers and home cameras if you try to connect other devices to them that are on a 5ghz frequency. They will not talk to each other.

Simon Wicki • Sep 19 '21

Very interesting write-up, Ben.
My biggest pet peeve is the time it takes to reconnnect to a different AP when walking around in the apt. They already run in a mesh network, but the reconnect is still there.

Does anyone know if I am I just running cheapo hardware or is that something that is there to live by?

Claro A Briones • Sep 20 '21

I agree with the penetration and range assertions. Another advantage 5g has over 2.4 is it operates at a higher frequency so it doesn't get as much RF interference. 2.4 is all over the place and it disrupts connectivity.

Brian Ng • Oct 4 '21

This is what should be addressed beside the range issue. I have a mobile BTS near my house and it's impossible to have 2.4GHz working normally (the AP is just about 1m away tbh). Switching to 5GHz and the connection is more stable.

Simon Wicki • Sep 20 '21

Thanks for your reply.
I asked Malte from one of your tweets (twitter.com/cramforce/status/14395...). He was very kind to state that this problem has been solved already. Not all hardware do solve it, but many do.

leob • Sep 18 '21 • Edited

I remember the struggles with Wifi "in the old days" (partially attributable to how horribly Windows handled it), nowadays your ISP's modem almost always comes with capable Wifi built in, so in most cases we can just enjoy that & call it a day ;)

Ricardo Sueiras • Sep 18 '21

Great thread. I wonder if anyone has done any benchmarks. My AP supports 2.4 and 5 and I have to say I’ve had way less issues/problems with 5 even through distance and walls (live in a 30’s house with good size load bearing walls). This has certainly made me think and I might try to do my own experiments to find out more.

Rémy 🤖 • Sep 24 '21

5-years-old version:

Suppose that wifi signal is like light. The 2.4 Ghz is red and the 5 Ghz is blue and green.

Windows are transparent to light. Walls and other objects are transparent to Wifi. It's just that they are usually a bit red-tinted so the blue and green of 5 Ghz are fading out quicker.
Suppose you can communicate by flashing a red light. You can only say "on" or "off" or let's 1 or 2. Now if you can flash a blue or green light you have "off", "blue" or "green" so that's 1, 2 or 3. In the same amount of time you can get more amount of information through.

Jen Chan • Sep 18 '21

I discover despite the channel being available I'm not really getting 5Ghz. I think it has to be enabled on my router...

ItsASine (Kayla) • Sep 18 '21

The benefit at least in my city apartment is being able to split my devices across both bands instead of clogging the one (like everyone else in my building...)