"Geoffrey S. Mendelson" wrote in message
...

If you have a ham license, then you can use 2.4gHz for data transmission,
but then you are restricted in transmission mode, encryption and data
content.

And wireless channels, as well. Some of the channels are outside the U.S.
ham bands. Since this is an amateur radio newsgroup, I made the (possibly
rash) assumption that OP was aware of these limitations. For amateurs in
the U.S., the main issue is encryption. Few of us can afford to get
anywhere near the power limits at these frequencies!

...

On Tue, 4 Jul 2006 08:30:46 -0400, xpyttl wrote:

....
Indeed, at 2.4 MHz, it is pretty easy to get antennas with amazing amounts
of gain. ......

Sigh... If only that were true! HI!HI!

Jonesy
--
Marvin L Jones | jonz | W3DHJ | linux
38.24N 104.55W | @ config.com | Jonesy | OS/2
*** Killfiling google posts: http//jonz.net/ng.htm

Beverly Erlebacher wrote:
I'm confused about this "access point" thing.

An access point is a device with an ethernet port on one side and a wifi
port on the other. In technical terms it would be called a "bridge". It
"bridges" two seperate network segments, although in this case they use
different topologies (100Base-T and WiFi).

Is that the same as a "router"?


The usual WiFi router consists of a four port ethernet hub (LAN ports),
a seperate single ethernet port (WAN port) and a WiFi access point.
It is set up to "route" between the single (aka WAN) port and the other
two ports, the LAN and WiFi. Most of what it does for routing is NAT (network
address translation) and some sort of IP tunneling.

If you ignore the WAN port and just use the LAN ports, you have a four port
hub and an access point.


Is it as simple as buying a second router (routers are familiar to me) and
just hooking that second router to the first router by cable and that would
extend my range by the distance of the cable connecting the two routers?

Yes. Just make sure to use the LAN ports. It would be best to use different
channels. Most WiFi clients are smart enough to use the channel that is the
strongest if they have access points on more than one with the same SSID.

Make sure to use encryption. Encryption is NOT to keep your data safe,
nothing can do that. If someone is intent on accessing your network, WEP
encryption will not keep them out.

What it is for is to convince the guy driving down the street looking for an
open network to send out SPAM, or "share" kiddie porn, to drive on.
Unfortunately, most users don't even change the SSID of their network, let
alone set an encryption key.

Having tuned in late, if you want to have an open network, look up PublicIP.
It's a "live cd" that runs on a PII or better (x86) computer and provides
all the functions you need to offer a secure and safe open network.

Geoff.

--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM
IL Voice: (07)-7424-1667 IL Fax: 972-2-648-1443 U.S. Voice: 1-215-821-1838
Visit my 'blog at http://geoffstechno.livejournal.com/

Rod Speed wrote:
Is one transmit and the other receive?
Or are they both transmit and receive?

They're normally both transmit and receive.

That's a shame. Here in Israel we are limited to 100mw EIRP, which
severly limits the transmit antenna. There is NO limitation on the
receive antenna.

Geoff.
--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM
IL Voice: (07)-7424-1667 IL Fax: 972-2-648-1443 U.S. Voice: 1-215-821-1838
Visit my 'blog at http://geoffstechno.livejournal.com/

Geoffrey S. Mendelson wrote
Rod Speed wrote

Is one transmit and the other receive?
Or are they both transmit and receive?

They're normally both transmit and receive.

That's a shame. Here in Israel we are limited to 100mw EIRP, which severly
limits the transmit antenna. There is NO limitation on the receive antenna.

A receive antenna has no EIRP, it doesnt radiate any real power.

hehe -- getting gain at the antenna isn't such a big deal ... getting the
goo TO the antenna is a whole 'nuther can of worms. It's pretty easy to
come up with 10 dB of gain and 20 dB of feedline loss! Of course, for WiFi,
we're often interested in gain AND omnidirectional -- that is something of a
challenge.

...

"Allodoxaphobia" wrote in message
...
On Tue, 4 Jul 2006 08:30:46 -0400, xpyttl wrote:

...
Indeed, at 2.4 MHz, it is pretty easy to get antennas with amazing
amounts
of gain. ......

Sigh... If only that were true! HI!HI!

Jonesy
--
Marvin L Jones | jonz | W3DHJ | linux
38.24N 104.55W | @ config.com | Jonesy | OS/2
*** Killfiling google posts: http//jonz.net/ng.htm

xpyttl wrote:
hehe -- getting gain at the antenna isn't such a big deal ... getting the
goo TO the antenna is a whole 'nuther can of worms. It's pretty easy to
come up with 10 dB of gain and 20 dB of feedline loss! Of course, for WiFi,
we're often interested in gain AND omnidirectional -- that is something of a
challenge.

POE! POE! POE! (Power over ethernet). Put the access point at the antenna,
run a cat-5 cable (4 twisted pairs) to it. Four get used for the network
connection, 4 get used for DC.

Not only does it work well, but CAT-5 wire is cheap, 2.4gHz low loss coax
is not.

Geoff.
--
Geoffrey S. Mendelson, Jerusalem, Israel N3OWJ/4X1GM
IL Voice: (07)-7424-1667 IL Fax: 972-2-648-1443 U.S. Voice: 1-215-821-1838
Visit my 'blog at http://geoffstechno.livejournal.com/

Rod Speed wrote:
Geoffrey S. Mendelson wrote

Rod Speed wrote


Is one transmit and the other receive?
Or are they both transmit and receive?


They're normally both transmit and receive.


That's a shame. Here in Israel we are limited to 100mw EIRP, which severly
limits the transmit antenna. There is NO limitation on the receive antenna.


A receive antenna has no EIRP, it doesnt radiate any real power.




Actually, when properly matched, it radiates half the received power.

"John - KD5YI" wrote in message news:XLQrg.2896$bd4.372@trnddc01...
Rod Speed wrote:

A receive antenna has no EIRP, it doesnt radiate any real power.

Actually, when properly matched, it radiates half the received power.


How do you get that?
If the receiver input impedance is matched to the antenna, all the
received power is absorbed. There is no reflection. There is no radiation.

If the receiver matching is for optimal noise figure, there may be
some reflection and reradiation, but there's nothing pinning it to
be half the received power.

Don

Don K wrote:
"John - KD5YI" wrote in message news:XLQrg.2896$bd4.372@trnddc01...
Rod Speed wrote:
A receive antenna has no EIRP, it doesnt radiate any real power.
Actually, when properly matched, it radiates half the received power.


How do you get that?
If the receiver input impedance is matched to the antenna, all the
received power is absorbed. There is no reflection. There is no radiation.

If the receiver matching is for optimal noise figure, there may be
some reflection and reradiation, but there's nothing pinning it to
be half the received power.

John is correct. A receiving antenna, when matched, reradiates half the
power it receives. An impinging field induces current in the antenna.
This causes radiation, just like the current in a transmitting antenna.
As it turns out, when the antenna is matched, the amount of power
radiated equals the amount of power delivered to the load, and that's
the best you can do. If you'd like a more in-depth and mathematical
explanation, you can find it in any antenna text, often discussed as
"scattering".

If a receiving antenna did absorb all the impinging power, it would be a
lot easier to make a shield or a stealth aircraft.

Roy Lewallen, W7EL