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A deep dive into why Wi-Fi kind of sucks

arstechnica.com

171–180 of 242 posts

Re: A deep dive into why Wi-Fi kind of sucks

#171
post #14

Earlier quoted context omitted.

Which router do you recommend? Is the 5G band consistently worse than the default (i.e. constant connection drops) or is that just my experience?

Physics is the issue here. The 5GHz band is going to be better if you are in the same room as the AP. However, it does not penetrate walls as well, so depending on your set up (and the construction of your walls), that might explain your experience.

In two houses on two routers I've had horrendous experience with 5GHz.

Re: A deep dive into why Wi-Fi kind of sucks

#172
post #14

Earlier quoted context omitted.

Which router do you recommend? Is the 5G band consistently worse than the default (i.e. constant connection drops) or is that just my experience?

An unfortunate side effect of being in the industry is that I constantly have a surplus of enterprise-grade hardware at home. It's been a while since I looked at consumer hardware. Apple's Airports were solid, but have been discontinued. I've used both of the OnHubs and both were performant / stable. I've heard generally good things about Google's new Wi-Fi pucks, and Netgear's nighthawk series. 5G is the better of t…

You can also do channel bonding on 5G and use 40MHz channels. Almost double the capacity!

Re: A deep dive into why Wi-Fi kind of sucks

#173

If anyone is involved in the standards committees -- please try to make the naming more user-friendly. My non-techie friends are totally confused by A, AC, AX, B, G, N, WiMax. No need to reveal the inner workings of the standards committees to the public. Simple numbering would help.

You mean like 3G/4G/LTE?

Re: A deep dive into why Wi-Fi kind of sucks

#174
post #97
post #14

Earlier quoted context omitted.

Which router do you recommend? Is the 5G band consistently worse than the default (i.e. constant connection drops) or is that just my experience?

My phone doesn't do 5GHz, but other than that, 5GHz is significantly better until you get about 3-5 walls between you and the router. In general, 5GHz is way better for apartments (less channel congestion, apartments are usually smaller than houses), and 2.4GHz is better for non-urban houses (better wall penetration). For urban houses (I can see 15+ 2.4GHz networks from my living room; in a larger city it could be wo…

Do you use your phone lines? If not check if they are cat 5. If so, use that instead of the power lines.

Re: A deep dive into why Wi-Fi kind of sucks

#175
post #80

The author kinda bungles his analogy/explanation of collision avoidance and detection. Wireless networks don't use CSMA/CD. They use CSMA/CA. There's a huge difference, and it's one big reason why wireless throughput won't ever come close to PHY speed. Wired ethernet uses CSMA/CD and it's one of the reasons it won the LAN networking wars of the 80's and 90's.

Do today's wired networks (1G+/FD/Cat6/fiber) still use CSMA/CD? I was under the impression that they don't.

No, since wired networks are full duplex and are their own collision domains. No need to do carrier sensing at all.

Re: A deep dive into why Wi-Fi kind of sucks

#176

Earlier quoted context omitted.

Yes and nothing special, as long as the clients and AP are moving consistent to each other. If the client is moving >10MPH relative to a fixed AP (i.e. you're driving past the AP in your car), Wi-Fi doesn't handle that well. Your movement creates Doppler shift in your RF signal, which Wi-Fi can't adjust for (vs. e.g. LTE which does).

Doppler shift in a radio wave at 10 mph? Wouldn't the Doppler shift be around 36 Hz in that case [1]? That's about 0.015 PPM. Seems temperature would have a bigger impact on frequency stability than that. [1] ∆f = f0 * (∆v/v0) = 2.4 GHz * (4.5 / 3e8) = 36 Hz (using 10 mph = 4.5 m/s) Edit: I'm certainly not an expert in RF. I checked my intuition against the datasheet of a radio module I've been working with (RFM69HCW…

Keep in mind, modern WiFi uses OFDM where the signal is transmitted via a number of simultaneous carriers offset by very small frequencies. So while the center of the 20Mhz band might be shifted just a little the small carries might be shifted far enough onto each other that the signal is unintelligible.

Re: A deep dive into why Wi-Fi kind of sucks

#177
post #160

I once had the opportunity to listen to an extremely talented WiFi expert from Aruba Networks explain on a whiteboard to a rapt audience of infrastructure engineers how this works. And how adding multiple SSIDs is a contributing factor to this problem. The most fascinating piece was what he called the "butter factor". The closer a substance is in consistency to butter, the more it will absorb WiFi signals. Aruba had…

> They had to use directional antennae mounted mounted at eye level down each aisle of the factory.

Did they ever mention the permanent, cumulative damage concentrated 2.4ghz RF does to the human eye?

Re: A deep dive into why Wi-Fi kind of sucks

#179
post #177
post #160

I once had the opportunity to listen to an extremely talented WiFi expert from Aruba Networks explain on a whiteboard to a rapt audience of infrastructure engineers how this works. And how adding multiple SSIDs is a contributing factor to this problem. The most fascinating piece was what he called the "butter factor". The closer a substance is in consistency to butter, the more it will absorb WiFi signals. Aruba had…

> They had to use directional antennae mounted mounted at eye level down each aisle of the factory. Did they ever mention the permanent, cumulative damage concentrated 2.4ghz RF does to the human eye?

Care to cite a credible source for this claim?

Re: A deep dive into why Wi-Fi kind of sucks

#180
post #56

There is a German tech saying that goes "Wer Funk kennt, nimmt Kabel" ("Those who know wireless, use wires").

Funk means wireless ??

In this context, yes. More literally, Funk means radio, and the word for wireless would be "drahtlos".
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