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The Wi-Fi only works when it's raining

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Re: The Wi-Fi only works when it's raining

#131

Post by obi1kenobi »

IshKebab wrote: post #115
obi1kenobi wrote: post #103

Earlier quoted context omitted.

I'm the author. Among other things, it's a distance problem -- WiFi can go through walls when the router is right there. But distance attenuates the signal as distance squared, and in this case we're talking about hundred+ yards/meters instead of just a couple.

> in this case we're talking about hundred+ yards/meters instead of just a couple. Sure but didn't you say you were using directional antennas?

No antenna is directional enough to overcome n^2 scaling. Especially not the mid-tier consumer-grade hardware I would have had access to at the time.

Rough rule of thumb, a consumer-grade directional antenna (at least at the time, maybe they've improved in the last 10yrs) will give your signal strength a one-digit multiplier (say ~8x), meaning ~7-10dB. But that n^2 means that improvement only takes you 2-3x farther, not 8x.

Here we're talking about ~100x the distance, which would need a 10000x = 40dB improvement in signal strength. AFAIK an antenna like that would cost more than the entire city block where I grew up

Re: The Wi-Fi only works when it's raining

#132

Post by jonathanlydall »

When I started reading this it seemed like “internet” and WiFi were being conflated, for example on our neighbourhood WhatsApp group there are often people asking “Is anyone else’s WiFi down?”, when what they should ideally be asking is if anyone else’s (fibre) internet is down. In such cases I internally frown a little, but leave it there.

Anyway, for the situation in this link, they actually have a WiFi bridge from their house to their office which has the connection to an ISP, so it is absolutely accurate to say the WiFi was down in this case.

Re: The Wi-Fi only works when it's raining

#133

Post by tantalor »

superb_dev wrote: post #50
tantalor wrote: post #43

I dislike calling this "magical thinking", just because the plausible causal relationship takes a little time to discover, it's not implausible at the outset. In fact, the causal relationship between rain & wifi is taken as a given by the author: > If anything, rain makes wireless signal quality worse It's not too surprising to discover a causal relationship between two things we already know are causally related.

You don't think it's unusual to find a positive correlation where there is usually a negative correlation?

Unusual yes, magical no

Re: The Wi-Fi only works when it's raining

#134

Post by obi1kenobi »

kyawzazaw wrote: post #112
themadturk wrote: post #34

Earlier quoted context omitted.

Well, that would have meant interacting with other people...

can't really be that entitled and ask them to cut their tree (or even if you do it by youself)

(I'm the author.) I really like trees! So I wouldn't have wanted to cut it down or even prune it.

Also, I hate operational (ongoing) solutions to problems. Pruning it would have been exactly that kind of solution -- we'd have had to prune it regularly or else it would have kept being a problem every so often.

The hardware fix was easier: our equipment was already a bit old and slow, the upgrade fixed the rain problem while also making it faster, and it's not something we've had to tweak since. I've long since moved out, but my parents still use that same 802.11n bridge today!

Re: The Wi-Fi only works when it's raining

#136

Post by helph67 »

1024core wrote: post #117

Reminds me of that old tale about a lady whose phone would not ring, and her dog would bark before the phone rang.

Just the basic facts... Climbing a nearby telephone pole and hooking in his test set, he dialed the subscriber's house. The phone didn't ring. He tried again. The dog barked loudly, followed by a ringing telephone. Climbing down from the pole then he found:

a. Dog was tied to the telephone system's ground post via an iron chain and collar.

b. Dog was receiving 90 volts of signalling current.

c. After several jolts, the dog was urinating on ground and barking.

d. Wet ground now conducted and phone rang.

Which goes to prove that some grounding problems can be passed on.

Re: The Wi-Fi only works when it's raining

#137

Post by neon5077 »

Here's my own 500 mile email story. This happened to me about a year ago.

Just a normal day at the office when suddenly the internet drops out, except for my machine. Everyone else has a network connection, but no internet. Except for me, I can't reach devices on the local network, but I can reach anything outside.

Now, our network is not large or complicated. We have a consumer grade ONT and WiFi router provided by the ISP, and a big unmanaged ethernet switch. There's really nothing to go wrong here.

After some debugging, I notice that I have been assigned an IP address in my ISP's public block. Tracert seemed to show no local network between me and the WAN. It was as if the router had somehow connected my WiFi client directly to the ONT, bypassing the local network. That only barely makes sense, but it was my best guess so I condemned the router.

Next day, new router, same problem. I couldn't explain it. This time though, I didn't have an internet connection, but local network was reachable. Some sanity restored, ar least.

Turns out that our fiber line had been accidentally cut during construction work. Once the ISP fixed that, all was normal.

The question remains, how did I have internet connection through a severed fiber line? It's not likely that the router had a bizarre failure right before the line was cut. I suppose it's possible that Windows had sneakily connected me to some other WiFi network, but then why did I have a weird IP address?

I have no explanations

Re: The Wi-Fi only works when it's raining

#138

Post by obi1kenobi »

femto wrote: post #126
remram wrote: post #122

Earlier quoted context omitted.

"They said it does X but really it does X and the superset Y" In other words, they were correct then?

They are describing a situation in which a line-of-sight channel is replaced with a rich/complex channel: the exact conditions under which MIMO distinguishes itself from beamforming. I'd say incomplete rather than incorrect, and the complete story is worth knowing as it makes the solution used more interesting.

(Author here.) Yeah, I get where you're coming from. Ultimately, this was an editing decision first and foremost.

Beamforming is cool and magical, and MIMO even more so. The post wasn't intended as a primer on wireless technology, just as a fun read for folks to enjoy. I tried to sprinkle in some nerd-snipe-quality technical detail and offer links for folks who might want to dig in, and MIMO is explicitly discussed in both the 802.11n and in the several links on beamforming I provided.

I barely managed to explain beamforming without that sidenote turning into a paragraph of its own. I don't think I could have done MIMO justice in a sidenote.

Re: The Wi-Fi only works when it's raining

#139

Post by swores »

Sharlin wrote: post #63
drb999 wrote: post #55

Reminds me of an extremely similar case with a long distance microwave link at a mobile telecom provider in Australia that I worked for. They relied quite heavily on microwave link chains and this particular one was in northern Queensland where fixed lines were hard to find and no local engineers were locally present/aware of the changing environment. Every week day + Saturday, from 7-3 the link would keep cutting ou…

Amazing. Reminds me of the fact that militaries really don't want wind turbines in areas where good radar coverage is important (case in point: the Finnish Defense Forces anywhere near the Russian border); even though the blades aren't metal, they're still a source of noise and radar shadow.

I'm not at all knowledgable about this, but: is it feasible (and if so, hard?) or impossible to have some sort of live reporting from the turbines about the speed/position of their blades that connects to the radar system allowing it to ignore what it knows to be turbine noise/shadow and therefore be able to have turbines there and still get good radar?
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