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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

#261

Post by redbell »

jordigh wrote: post #15

Let me see if I'm the first one to link to that classic story in the same series, "I cannot send email further than 500 miles" http://www.ibiblio.org/harris/500milemail.html Or the Magic/More Magic switch http://www.catb.org/jargon/html/magic-story.html It's fun when physical reality meets the abstract models that we have built in our heads of these machines.

This is a true classic that never gets old!

Discussed many times here in HN:

1. https://news.ycombinator.com/item?id=37576633

2. https://news.ycombinator.com/item?id=23775404

3. https://news.ycombinator.com/item?id=9338708

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

#263

Post by juitpykyk »

swores wrote: post #252
Sharlin wrote: post #156

Earlier quoted context omitted.

Well, you can't just ignore a radar shadow or noise. Just like GP's point-to-point microwave link couldn't just "ignore" the crane. You can't make a bad Wi-fi connection faster by just telling your computer to ignore the wall between you and the hot spot. A wind turbine is a solid obstacle that conceals stuff behind it, and even if a single turbine might not be a big deal, most commonly someone interested in harnessi…

My (probably ignorant) thinking was that if there weren't propellers, just stalks, they could be arranged in a pattern that radar setups at multiple locations could see through gaps and between them have no dark spaces caused by the towers. Leaving the problem that the blades essentially block out an entire circle, but if the radar software knows the position of every turbine's blades (by a combination of turbines re…

Depends on the width of the radar beam. They are certainly not thin like a laser. It might not fit in the gap between the blades.

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

#264

Post by Aissen »

thekevan wrote: post #176

This is a bit ridiculous. How can you know that you have a ling of sight element to you network and not check that as the very first thing when you hear about rain effecting the wifi?

Have you never spent hours (or even days!) debugging an issue that seemed obvious in retrospect, once all incorrect assumptions have been eliminated?

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

#267

Post by robocat »

phyzome wrote: post #164
gerdesj wrote: post #157

Some years ago I put in a point to point wifi link for a family member, from house to garage "block". I specified a pair of Ubiquity Nanostations which are tiny, PoE powered and have a decent range. The house end is inside a UK standard tiled roof - dense 3/4", allow for slat, so 1"+ thick and dense material. The other end is 20m away (LoS) and external mounting was forbidden. The garage block has foil lined Kingspan…

Why was subterfuge required? Something is missing from this story.

If you are renting then you might not be allowed to install an aerial on the building. There are situations where you need council permission to install an aerial or it may be forbidden e.g. listed historic buildings.

Also see: https://www.townplanning.info/permitted-development/househol...

Just what I found doing a quick search.

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

#268

Post by dmurray »

LtdJorge wrote: post #251
dmurray wrote: post #167

Earlier quoted context omitted.

Without going into anything confidential - we had some of our own hardware, but generally rented capacity from firms like [0]. Some towers were custom built for HFT, some were shared with other types of users. A famous blog post investigating some of the towers as an outsider, at [1], will be of interest to you. If you want to guess where they are, get a globe, find the datacentres where electronic exchanges operate…

Is the microwave setup quicker than going through fiber nowadays? I only mean in terms of latency.

Traditional optical fiber has glass in the middle. The speed of light in glass is only about 66% of the speed in air, so microwave is always faster if you can get a reasonably straight path for both.

There now exists hollow-core fiber, where the light travels down an air gap in the middle, which is theoretically competitive with microwaves/lasers/etc. How much this is being used is a secret, but microwave transmission definitely hasn't gone away.

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

#269

Post by gerdesj »

cyberax wrote: post #198
gerdesj wrote: post #179

Earlier quoted context omitted.

Thanks. I've never run Asterisk on Ubuntu. FreePBX is CentOS based which is mostly what I've run Asterisk on. I only started to worry about Ubuntu around 2012. That mad IPv6 address thing must have stuffed up more than just a VoIP negotiation packet. DNS switches from UDP to TCP when responses get too large.

DNS is affected, but differently. It's mostly DNSSEC signatures that cause trouble nowadays. SIP is special because the signalling and media protocols are separate. So when a call is being established, the parties exchange their media endpoint locations. This necessarily means that the server has to list its IPs (or DNS names) so that the client can choose the best one. And as a quirk of SIP, it sends the entire set…

"SIP is special".

Yes, I know, just like ftp 8) I do hope that whomever invented putting the control channel in a separate stream from the data is mildly discomforted. Mind you, all that stuff was invented a very long time ago, when trousers were a major trip hazard.

My go to fix is "symmetric RTP", which seems to have become a default over the last decade or two.

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

#270

Post by robocat »

MerManMaid wrote: post #194
maxglute wrote: post #83

Earlier quoted context omitted.

I have a fancy microwave that degrades my fancy bluetooth headset but not others. Did replacing the wifi card work? I'm wondering if I need to switch up my expensive microwave, or expensive headphone, because replacing bluetooth dongle (with another generic one with same chipset) hasn't resolved issue.

Microwaves use the 2.4ghz spectrum but typically not with any real precision which means that while in use they just tank the 2.4ghz spectrum. *As an aside, one of my favorite things I get to do at work is when onboarding new Jr. Net Engineers is getting them take our spectrum analyzer into our office kitchen and instructing them to watch the spectrum turn bright red while I make a bag of popcorn. Anyhow to get to yo…

Good debugging story:

https://www.theguardian.com/science/2015/may/05/microwave-ov...

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