AirPort Extreme Base Station question

I have an Intel iMac and two G4 Powerbooks. The iMac should be 802.11n
capable, but certainly not the G4s. The base station appears to operated
at either of two frequencies. If I choose the higher frequency, which is
less used (I live in an apartment building), I think my iMac will be OK.
But will I not be able to use my G4s? Do I have to choose the lower
frequency to include them?

 

Correct.

If you set the Airport Extreme to run at 5 GHz, it will be compatible
with devices which support 802.11n and 802.11a.

Earlier Macs use 802.11g (Airport Extreme) or 802.11b (Airport), which
operate at 2.4 GHz.

To allow these Macs to connect to the wireless network, you will have to
run your Airport Extreme base station in the 2.4 GHz band, and make sure
it is set to "802.11n (b/g compatible)", not "802.11n only (2.4 GHz)".

If you have two base stations, you can set them up with different
frequencies, which would allow you to dedicate one to the 2.4 GHz
machines (b/g) and keep your iMac in the less cluttered 5 GHz band.

A technical advantage of 5 GHz is that it supports wide channels, which
allow almost twice the data rate which can be achieved at 2.4 GHz (up to
250 Mbps instead of 130 Mbps for 802.11n).

This would only be significant for internal file transfers between
computers. Your Internet connection definitely won't be that fast, and a
hard drive attached to the base station probably won't go fast enough to
benefit from the higher speed (due to the limitations of USB 2.0).

A disadvantage of 5 GHz is that the radio signal doesn't pass through
physical objects as well, resulting in shorter range if there are walls
between the base station and computer.

My Airport Extreme base station is roughly in the middle of my house,
and I get good coverage everywhere inside at 2.4 GHz, but lose the
signal in some distant rooms at 5 GHz.

 

I think if you enable the 802.11n (802.11b/g compatible) mode,
that you play in the 2.4GHz band. I am NOT positive, but that is
what I am sensing when I did some google searches on the subject.

What I did for my home is to keep my old 802.11b/g WiFi base
station and configured things so that I used the new Airport
Extreme at "802.11n only (5 GHz)" setting.

The older 802.11b/g base station was set to disable the DHCP and
NAT services. That is to say, I configured it so that it was a
bridge.

I connected the older 802.11b/g to my 802.11n router via ethernet
cable. Since they are operating on different frequency bands it
doesn't matter if they are near each other or in separate rooms
(in my case I happen to have an ethernet cable running from the
dinning room to an upstairs back bedroom, so that is where I put
my 802.11b/g base station).

In this instance made a decision to create a separate SSID network
name for the 802.11n which was different from the 802.11b/g
network. I did this since my 802.11b/g devices were not going to
ever talk to the 802.11n network, so it was not necessary to worry
about maintaining a roaming network.

HOWEVER, if you did want to setup a roaming network, where an
802.11n compatible laptop might roam far enough from the 802.11n
base station to loose it signal, but still be in range of an
802.11b/g base station, then you would give all your base stations
the exact same SSID name and the exact same WPA (preferably) or
WEP password. That way when the roaming 802.11n laptop found that
the signal from the 802.11b/g base station was stronger, it would
just hope from one WiFi base station to another without loosing a
beat.

NOTE: It is important that in any home setup where there are
multiple WiFi base stations that there ONLY be one active router
(the one attached to the broadband modem). All other WiFi base
stations should be configured to disable their DHCP and NAT
services and just act as WiFi extenders or ethernet to WiFi
bridges. That way everything on the same home subnet and everyone
has the same router in listed in their Network System Preferences.

If you do not disable the routing functions in the other WiFi base
stations, then you may find that various Bonjour sharing features
do not work as expected (shared printers, file servers, etc... may
not be seen across router boundaries).

Good luck and enjoy.

Bob Harris