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by obi1kenobi 804 days ago
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
1 comments
Dylan16807 804 days ago
Won't 20dB at each end do the job? You can get 16-17dB antennas for $35 these days. And a wire parabolic dish promising 23dB for $200.

7-10dB matches the antennas I personally use, but those antennas are smaller than my phone. You can get a lot more out of a three foot spike or a two foot dish.

(I'm assuming 2.4GHz and hoping they're not lying about the gain.)

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obi1kenobi 803 days ago
Right. This is a multiple timelines problem.

This story happened a bit over 10 years ago at this point. At the time of the story, the Wi-Fi bridge was already almost 10 years old -- we'd had the same equipment since I first remember getting internet at home.

That means the antennas at the start of the story were mid-2000s mid-tier consumer level equipment. I don't think a 16-17dB antenna would have been $35 at the time, in either mid-2000s dollars or in today's dollars. I also grew up in a country much poorer than the US, where $35 could feed a family for a week.

At the end of the post, we upgraded to 802.11n antennas (but still tech from 10+ years ago) which solved the problem by being newer, nicer, and having beamforming + MIMO capability which let them be more tolerant of obstacles (effectively, get more dB at the same emitted power level).

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Dylan16807 803 days ago
I'm not trying to critique the solution, I just think the decibel issue isn't so dire and other factors were more important. Which is supported by the way the problem was fixed.

As far as what was available at the time, I can't think of a super easy way to check that far back, but I will note that the 17dB stick antennas on Amazon have been available at the same price or cheaper for about 10 years.

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