3 ms·

I think part of it is that WiFi (2.4ghz and 5ghz) are both not very penetrating compared to most of the amateur bands (sub 1ghz). That means that long range co

I think part of it is that WiFi (2.4ghz and 5ghz) are both not very penetrating compared to most of the amateur bands (sub 1ghz). That means that long range commercial use of them would be very difficult. This is why companies like Time Warner, who are trying to use them for commercial wifi end up installing special modems/routers in customers homes to be able to accomplish the task.

nickpsecurity 11y ago
Ahhhh. That makes sense. Maybe a multi-year trial is in order.
madengr 11y ago
Ham operators can run 1.5kW on the 2 GHz wifi band.
- nickpsecurity 11y ago
  Suddenly makes less sense then.
- tomkinstinch 11y ago
  We can, but the norm (and law via FCC part 97) is for one to use "the minimum power necessary to carry out the desired communications." So if you need 1.5kW to reach your wifi robot on the other side of the valley, go for it, but otherwise quieter is the rule. There's a subculture of hams who try to see how far away they can make contacts on minimal power (miles per milliwatt). It's not unheard of to make trans-Atlantic contacts using 100mW, by bouncing the signal off the ionosphere. It's possibly to reach most of the globe on 25W via PSK31, with sound cards handling the signal processing.
  - nickpsecurity 11y ago
    "It's not unheard of to make trans-Atlantic contacts using 100mW, by bouncing the signal off the ionosphere. It's possibly to reach most of the globe on 25W via PSK31, with sound cards handling the signal processing." That's freaking wild. I remember my brief forays into the subject also had me fascinated with the idea of meteor burst communication where I was bouncing stuff off exploding meteors. Haha. With further digging, the source of my first link was surprising: https://www.nsa.gov/public_info/_files/cryptologic_quarterly/meteo_burst.pdf https://www.nsa.gov/public_info/_files/cryptologic_quarterly... http://www.dtic.mil/dtic/tr/fulltext/u2/a228641.pdf http://www.dtic.mil/dtic/tr/fulltext/u2/a228641.pdf The second wasn't as DTIC is one of the most badass, if little-known, resources for technical information. Obscure, but great, insights buried in that organizations records.
    - tomkinstinch 11y ago
      If you're interested in some of the latest in low-power digital communication, check out the software of Joe Taylor, K1JT: http://physics.princeton.edu/pulsar/k1jt/ http://physics.princeton.edu/pulsar/k1jt/ If his name seems familiar, it's because it's the same Joe Taylor who was awarded the 1993 Nobel Prize in Physics (for his radioastronomy work on pulsars): http://www.nobelprize.org/nobel_prizes/physics/laureates/1993/taylor-bio.html http://www.nobelprize.org/nobel_prizes/physics/laureates/199...
      - nickpsecurity 11y ago
        Thanks for the link. Pretty badass. Bookmarking it and passing it along.

nickpsecurity 11y ago

Ahhhh. That makes sense. Maybe a multi-year trial is in order.

madengr 11y ago

Ham operators can run 1.5kW on the 2 GHz wifi band.

nickpsecurity 11y ago
Suddenly makes less sense then.
tomkinstinch 11y ago
We can, but the norm (and law via FCC part 97) is for one to use "the minimum power necessary to carry out the desired communications." So if you need 1.5kW to reach your wifi robot on the other side of the valley, go for it, but otherwise quieter is the rule. There's a subculture of hams who try to see how far away they can make contacts on minimal power (miles per milliwatt). It's not unheard of to make trans-Atlantic contacts using 100mW, by bouncing the signal off the ionosphere. It's possibly to reach most of the globe on 25W via PSK31, with sound cards handling the signal processing.
- nickpsecurity 11y ago
  "It's not unheard of to make trans-Atlantic contacts using 100mW, by bouncing the signal off the ionosphere. It's possibly to reach most of the globe on 25W via PSK31, with sound cards handling the signal processing." That's freaking wild. I remember my brief forays into the subject also had me fascinated with the idea of meteor burst communication where I was bouncing stuff off exploding meteors. Haha. With further digging, the source of my first link was surprising: https://www.nsa.gov/public_info/_files/cryptologic_quarterly/meteo_burst.pdf https://www.nsa.gov/public_info/_files/cryptologic_quarterly... http://www.dtic.mil/dtic/tr/fulltext/u2/a228641.pdf http://www.dtic.mil/dtic/tr/fulltext/u2/a228641.pdf The second wasn't as DTIC is one of the most badass, if little-known, resources for technical information. Obscure, but great, insights buried in that organizations records.
  - tomkinstinch 11y ago
    If you're interested in some of the latest in low-power digital communication, check out the software of Joe Taylor, K1JT: http://physics.princeton.edu/pulsar/k1jt/ http://physics.princeton.edu/pulsar/k1jt/ If his name seems familiar, it's because it's the same Joe Taylor who was awarded the 1993 Nobel Prize in Physics (for his radioastronomy work on pulsars): http://www.nobelprize.org/nobel_prizes/physics/laureates/1993/taylor-bio.html http://www.nobelprize.org/nobel_prizes/physics/laureates/199...
    - nickpsecurity 11y ago
      Thanks for the link. Pretty badass. Bookmarking it and passing it along.