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Comment by nammi | Hacker News Reader

Barely related, but reminded me that a recent comment here linked to this DEFCON talk from a former darknet vendor. He claimed to use WiFi from a house a mile away using a Yagi antenna

https://www.youtube.com/watch?v=01oeaBb85Xc

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With the right directional antenna you can already go like 10 miles and more. I certainly went over 1 km like 17 years ago just by using a grid reflector antenna connected to a cheap consumer 802.11b access point using legal power and a normal PCMCIA card with no external antenna on the other side. The point of the technology should be to allow long range communications with some speed restrictions but without sacrificing portability, which of course using a big directional antenna is not possible.

Isn't this illegal though? Aren't there limits that you are exceeding?

Yes, connecting a directional antenna is illegal because its gain "amplifies" the power in a given direction at the expense of all other directions. We of course didn't tell anyone, and back then there weren't many services that we could disrupt by pointing the antenna from the 9th floor of a building to a nearby hill:)

Using directional antennas is legal if you compensate by turning down the transmission power so that in the direction you are still transmitting the signal is no more intense than it would have been with omnidirectional antennas. That doesn't entirely defeat the purpose of using directional antennas because it still means that the receive side is focused specifically at the direction of interest and not picking up as much noise from irrelevant directions.

It's not illegal if you have a ham license, though. This allows for interesting hacks such as AREDN, which uses off-the-shelf WiFi hardware to run a mesh network, using high-gain (and usually directional) antennas to link larger nodes to each other:

http://docs.arednmesh.org/en/latest/arednGettingStarted/ared...

Depends on the country but in the US 10 miles with high gain antennas is easily within FCC rules. This is how WISPs operate.

Strange, I would have expected WISPs to have different regulations than consumers.

Pringles can wifi hacking has been around since 2005ish. I also remember someone using a spider strainer as a cheap handheld dish with a USB stick wifi transceiver placed near the focus.

https://www.instructables.com/Wifi-Signal-Strainer-WokFi/

At some point people were trying to set the record for the longest range wifi signal.

Even 20 years ago, WiFi distance records were mostly a matter of geography. The limit quickly became the curvature of Earth's surface, so the ideal geography was two mountains, separated by empty ocean in the middle, with easy access up their facing slopes.

There's troposcatter...bouncing off the troposphere. That's been around with microwave transmission for quite a long time. Requires a little more power though.

15+ years ago, my friend made a Yagi from a piece of wood and some nails, to connect to some open WiFi network from a block of flats a couple hundred meters away, in order to use it as a backup connection during semi-regular outages his ISP suffered from.

Ah, the joyful age of high school. No money or power to do things "the right way", but ample free time to skill up and hack your way around.

WiFi links over a mile is kind of amateurish. 3+ miles is easy to do if you've got a little bit of elevation and the surrounding land is flat

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