4 ms·

I've read about it years ago. Nice concept but if you have line of sight, WiFi with directional antennas is still better, you can get the standard 802.11g speed

by jotm 7y ago

I've read about it years ago. Nice concept but if you have line of sight, WiFi with directional antennas is still better, you can get the standard 802.11g speeds (~20Mbps real throughput) at even longer range and/or in worse weather (and even some trees in the way).

aidenn0 7y ago
Of course this device is probably legal while the WiFi setup would be definitely illegal (in the US).
- kawfey 7y ago
  FCC Part 15 allows for intentional radiators and is the basis for WiFi. With directional antennas, one can make a P2P link that reliably exceeds 10km. A world record has been set at 381km [https://www.wired.com/2007/06/w-wifi-record-2 https://www.wired.com/2007/06/w-wifi-record-2] but I don't know if the power level into the antenna was low enough to be Part 15 compliant. In college, I set up a 40km link with compliant power and antenna gains (using offset feed Primestar satellite dishes), and we use Part 15 compliant P2P wifi in St. Louis for our ham radio repeater control and data network with links between 2 and 5km.
- jotm 7y ago
  Even at maximum allowed tx power? Two of these should do 1km LoS easily at 90-150 mW: https://www.amazon.com/TP-Link-Directional-Parabolic-Connector-TL-ANT2424B/dp/B003CFATOW https://www.amazon.com/TP-Link-Directional-Parabolic-Connect... Of course, more power, more range (but also noise, so in reality you don't want more than ~200mW with standard routers) I used one of them to get a good 54Mbps connection with an AP ~400 meters away (5th floor to 2nd floor, only some treetops between). And that's basically the antenna just picking up the unboosted signal from the router (Linksys WRT54gs @ 85mW iirc)
- Sanzig 7y ago
  Unlicensed point-to-point links are permitted in the US provided that the Part 15 EIRP limits are respected. You are allowed to push up to 53 dBm of EIRP on the 5.8 GHz ISM band (30 dBm power + 23 dBm antenna gain), which gives a lot of link margin to play with.
  - aidenn0 7y ago
    I was actually unaware of the exceptions for dedicated p2p links. FWIW, You can get also get 52dBm of EIRP on 2.4GHz with a dedicated antenna by 22dBm of power with 30 dBi antenna gain. Also, the FCC specifically forbids running multiple pyshically-colocated unlicensed p2p links in parallel, and point-to-multipoint is also disallowed.
jascii 7y ago
I used to work for a WISP for a while, and it has been my experience that getting full 802.11g speeds on longer links in densely populated areas can be a real challenge due to spectrum congestion.

by jotm 7y ago

aidenn0 7y ago

Of course this device is probably legal while the WiFi setup would be definitely illegal (in the US).

kawfey 7y ago
FCC Part 15 allows for intentional radiators and is the basis for WiFi. With directional antennas, one can make a P2P link that reliably exceeds 10km. A world record has been set at 381km [https://www.wired.com/2007/06/w-wifi-record-2 https://www.wired.com/2007/06/w-wifi-record-2] but I don't know if the power level into the antenna was low enough to be Part 15 compliant. In college, I set up a 40km link with compliant power and antenna gains (using offset feed Primestar satellite dishes), and we use Part 15 compliant P2P wifi in St. Louis for our ham radio repeater control and data network with links between 2 and 5km.
jotm 7y ago
Even at maximum allowed tx power? Two of these should do 1km LoS easily at 90-150 mW: https://www.amazon.com/TP-Link-Directional-Parabolic-Connector-TL-ANT2424B/dp/B003CFATOW https://www.amazon.com/TP-Link-Directional-Parabolic-Connect... Of course, more power, more range (but also noise, so in reality you don't want more than ~200mW with standard routers) I used one of them to get a good 54Mbps connection with an AP ~400 meters away (5th floor to 2nd floor, only some treetops between). And that's basically the antenna just picking up the unboosted signal from the router (Linksys WRT54gs @ 85mW iirc)
Sanzig 7y ago
Unlicensed point-to-point links are permitted in the US provided that the Part 15 EIRP limits are respected. You are allowed to push up to 53 dBm of EIRP on the 5.8 GHz ISM band (30 dBm power + 23 dBm antenna gain), which gives a lot of link margin to play with.
- aidenn0 7y ago
  I was actually unaware of the exceptions for dedicated p2p links. FWIW, You can get also get 52dBm of EIRP on 2.4GHz with a dedicated antenna by 22dBm of power with 30 dBi antenna gain. Also, the FCC specifically forbids running multiple pyshically-colocated unlicensed p2p links in parallel, and point-to-multipoint is also disallowed.

jascii 7y ago

I used to work for a WISP for a while, and it has been my experience that getting full 802.11g speeds on longer links in densely populated areas can be a real challenge due to spectrum congestion.