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Another classic: Can log in while sitting down, can't log in when standing up. I need to find the reference ... Edit: OK, here's one version: https://www.reddit.com/r/talesfromtechsupport/comments/3v52p...
https://news.ycombinator.com/item?id=21978004
[Edit: I see this one has also been mentioned a few times already in the thread]
From the article: > One such piece of magic new to 802.11n Wi-Fi is called "beamfoming" That's not quite true. 802.1ln has MIMO (Multiple-Input Multiple-Output) processing, with "multiple" referring to the number of receiver and transmitter antennas. Beamforming is a special case of MIMO, and MIMO is a generalisation of beamforming. In a "Line-of-Sight" channel with no reflectors, MIMO converges to a beamforming solu…
In other words, they were correct then?
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.
> "Anyway, I asked one of the geostatisticians to look into it--"
> "Geostatisticians..."
> "--yes, and she's produced a map showing the radius within which we can send email to be slightly more than 500 miles. There are a number of destinations within that radius that we can't reach, either, or reach sporadically, but we can never email farther than this radius."
I adore when experts use their expertise to analyze real-world things like this and provide ridiculously thorough explanations :-D
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 very common thing in older automotive electronics, for example.
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?
From the article: > One such piece of magic new to 802.11n Wi-Fi is called "beamfoming" That's not quite true. 802.1ln has MIMO (Multiple-Input Multiple-Output) processing, with "multiple" referring to the number of receiver and transmitter antennas. Beamforming is a special case of MIMO, and MIMO is a generalisation of beamforming. In a "Line-of-Sight" channel with no reflectors, MIMO converges to a beamforming solu…
"They said it does X but really it does X and the superset Y" In other words, they were correct then?
I'd say incomplete rather than incorrect, and the complete story is worth knowing as it makes the solution used more interesting.
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?
TIL about Fresnel Zones! > Interestingly, objects outside the straight line between antennas can still cause interference! For best signal quality, the Fresnel zone between the antennas should be clear of obstructions. But perfection isn't achievable in practice, so RF equipment like Wi-Fi uses techniques like error-correcting codes so that it can still work without a perfectly clear Fresnel zone. I wonder if other w…
Terrestrial TV (some of which used bands that overlap FM radio) uses horizontal polarization.
The unusual internet setup is pretty important information to bury a few paragraphs in. Once that was explained it seemed like they should have started by checking nothing was blocking the antenna before tediously running around plugging the laptop into things and following cables and checking power supplies on the networking equipment? Hindsight is 20/20 but I correctly guessed the ending as soon as that information…
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