wifi from radio antenna?

I could probably find the answer to this by some research, but I'm too
lazy. :D We have the beginnings of free wifi in our city (Portland),
though it's still spotty, at best, since not all areas of the city are
'wired.' I was thinking about how the nodes only cover about 300'
each, then there's obstacles, interference, etc. Why can't they put up
one big antenna, like radio stations, and pump out 50k watts, or
whatever would be necessary to cover the entire city?

"sillyputty" <karmictaragem@2die4.com> wrote in message
news:1189062780.497176.239100@d55g2000hsg.googlegr oups.com...
>I could probably find the answer to this by some research, but I'm too
> lazy. :D We have the beginnings of free wifi in our city (Portland),
> though it's still spotty, at best, since not all areas of the city are
> 'wired.' I was thinking about how the nodes only cover about 300'
> each, then there's obstacles, interference, etc. Why can't they put up
> one big antenna, like radio stations, and pump out 50k watts, or
> whatever would be necessary to cover the entire city?

You would not want one powerful station like that. You would take a
cellular/mesh approach to do what you want. WIMAX cells can cover a pretty
good size area.

Look up WIMAX and WISP (wireless internet service provider)
>

sillyputty <karmictaragem@2die4.com> wrote:
> Why can't they put up one big antenna, like radio stations, and pump out
> 50k watts, or whatever would be necessary to cover the entire city?

Radio stations are one way. They have 50K watts, you just listen, you
don't transmit. You couldn't have a couple thousand transmitters going
back to one tower.

--
Clarence A Dold - Hidden Valley Lake, CA, USA GPS: 38.8,-122.5

sillyputty wrote:

> I could probably find the answer to this by some research, but I'm too
> lazy. :D We have the beginnings of free wifi in our city (Portland),
> though it's still spotty, at best, since not all areas of the city are
> 'wired.' I was thinking about how the nodes only cover about 300'
> each, then there's obstacles, interference, etc. Why can't they put up
> one big antenna, like radio stations, and pump out 50k watts, or
> whatever would be necessary to cover the entire city?

.... but now the wifi client in your laptop needs to be able to respond
(acknowledge packet received, send a packet, etc), using its own
50kw transmitter. Really shortens battery life!

"Roby" <roby@no-address.net> wrote in message
news:46dff826$0$6412$4c368faf@roadrunner.com...
> sillyputty wrote:
>
>> I could probably find the answer to this by some research, but I'm too
>> lazy. :D We have the beginnings of free wifi in our city (Portland),
>> though it's still spotty, at best, since not all areas of the city are
>> 'wired.' I was thinking about how the nodes only cover about 300'
>> each, then there's obstacles, interference, etc. Why can't they put up
>> one big antenna, like radio stations, and pump out 50k watts, or
>> whatever would be necessary to cover the entire city?
>
> ... but now the wifi client in your laptop needs to be able to respond
> (acknowledge packet received, send a packet, etc), using its own
> 50kw transmitter. Really shortens battery life!

The laptop would only need to use full power at the limit of the coverage of
the station, close in the laptop would not need to use such high power.:)

sillyputty <karmictaragem@2die4.com> hath wroth:

>I could probably find the answer to this by some research, but I'm too
>lazy.

That's ok, because I'm too lazy to research a proper answer.

>We have the beginnings of free wifi in our city (Portland),

Are you thinking perhaps of the MetroFi system:
<http://www.metrofi.com/content/maps/mf_portland_map_ad.html>

>though it's still spotty, at best, since not all areas of the city are
>'wired.'

Ummm... we gotta work on the terminology. One does not "wire" a
wireless network. I guess "install" might be a suitable substitute.
Personally, I prefer to "plant" an access point, since many of mine
are hidden inside fake plants, but nobody else likes the term. I'm
open to alternatives.

>I was thinking about how the nodes only cover about 300'
>each, then there's obstacles, interference, etc. Why can't they put up
>one big antenna, like radio stations, and pump out 50k watts, or
>whatever would be necessary to cover the entire city?

Well, lots of reasons, some of which others have mentioned. 50,000
watts means an AM broadcast band xmitter operating on about 1MHz with
a bandwidth of about 9KHz. Wi-Fi is 2,400Mhz, with a bandwidth of
about 26MHz, or about 3000 times the bandwidth of the AM station. So,
you could use a 50,000 watt AM transmitter to run wireless data, but
it would be at the speed of a really slow dialup connection, with only
one user for perhaps 100 square miles.

Need reading material on RF theory? I'm too lazy to supply a list but
might be able to generate a few buzzwords that you can insert into a
Google search.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Sep 6, 7:22 pm, Jeff Liebermann <je...@cruzio.com> wrote:

> I'm too lazy to supply a list but
> might be able to generate a few buzzwords that you can insert into a
> Google search.

LOL!

Antenna (and to an extent RF theory): The ARRL Antenna Book

--
HTH,
Curt

Windows Support Center
www.aumha.org
Practically Nerded,...
http://dundats.mvps.org/Index.htm

"Jeff Liebermann" <jeffl@cruzio.com> wrote in message
news:c2d0e3d6u6ajko21v9mb4187iegk63srg6@4ax.com...
| sillyputty <karmictaragem@2die4.com> hath wroth:
|
| >I could probably find the answer to this by some research, but I'm too
| >lazy.
|
| That's ok, because I'm too lazy to research a proper answer.
|
| >We have the beginnings of free wifi in our city (Portland),
|
| Are you thinking perhaps of the MetroFi system:
| <http://www.metrofi.com/content/maps/mf_portland_map_ad.html>
|
| >though it's still spotty, at best, since not all areas of the city are
| >'wired.'
|
| Ummm... we gotta work on the terminology. One does not "wire" a
| wireless network. I guess "install" might be a suitable substitute.
| Personally, I prefer to "plant" an access point, since many of mine
| are hidden inside fake plants, but nobody else likes the term. I'm
| open to alternatives.
|
| >I was thinking about how the nodes only cover about 300'
| >each, then there's obstacles, interference, etc. Why can't they put up
| >one big antenna, like radio stations, and pump out 50k watts, or
| >whatever would be necessary to cover the entire city?
|
| Well, lots of reasons, some of which others have mentioned. 50,000
| watts means an AM broadcast band xmitter operating on about 1MHz with
| a bandwidth of about 9KHz. Wi-Fi is 2,400Mhz, with a bandwidth of
| about 26MHz, or about 3000 times the bandwidth of the AM station. So,
| you could use a 50,000 watt AM transmitter to run wireless data, but
| it would be at the speed of a really slow dialup connection, with only
| one user for perhaps 100 square miles.
|
| Need reading material on RF theory? I'm too lazy to supply a list but
| might be able to generate a few buzzwords that you can insert into a
| Google search.
|
| --
| Jeff Liebermann jeffl@cruzio.com
| 150 Felker St #D http://www.LearnByDestroying.com
| Santa Cruz CA 95060 http://802.11junk.com
| Skype: JeffLiebermann AE6KS 831-336-2558