New iMac Cant Hold Internet Connection (and finds a lot of networks....)

Question

Hello,
I have one of the new 20" iMacs released 8/7. My problem is that my iMac cant hold an internet connection and it finds a lot of possible networks to which it can connect.
I am certain the issue lies with the iMac because my old Powerbook G4 has no problems connecting to the internet and it is sitting literally next to the iMac. Furthermore, I actually had purchased an iMac about a week ago and that one had no problems connecting to the internet either. (I returned that one when the new iMacs were released.) So that means 2 Macs had no problems connecting to the internet from the same location yet this new iMac does.
One thing I have noticed about this new iMac is that it detects many more networks than my Powerbook or the iMac from last week. I live in Manhattan so there are networks everywhere. Sometimes the iMac will give me 15 or so different networks to connect to and seconds later the choices drop to 5 or so. When I try to connect to the network I want (my network) the connection doesnt hold and it frequently drops. It takes me forever to download anything. I have to write this post on my Powerbook. My Powerbook only detects 2 or 3 possible networks to connect.
I rebooted, etc. and that did not work. I shut the Powerbook down so that it would not "compete" with the iMac and that did not work either.
Any suggestions/ideas?

Answer 1

Hello Wireless groupies:
I have had wireless problems with my laptop and my power mac this week, but all is well for me now.
The grass roots issues of wireless communication in terms of physics are related to amplitude and frequency. The amplitude is controlled (signal strength) by the power setting of the router and the portable device. The amount of power in the signal is measured in watts per square meter and is controlled by the broadcasting units settings.
The frequency at which the router broadcasts is changed by channels available in both units. I believe the portable units scan each channel for base station transmissions just like the radio in your car/lorry . The frequencies associated with each channel on the base transmitter can be assigned by the user for the best reception in the local broadcast area, most likely your home. The area which you operate has many different interference parameters which degrade signal strength just as in your portable radio reception. In the base station world it is based upon digital transmission encrypted (D to A) into an analog signal then decrypted at the laptop from analog to digital signal.(A to D). Experimentation is probably the only method to determine which is the best frequency to operate between your devices.
It should be noted that the new Imac's have an extended frequency range because they use a 'N' class wifi set of components. The N class wifi allows for higher frequencies and extended ranges. A base station which is a G class wifi can only broadcast in the lower frequency range and hence the availability of the higher frequencies of the new Imac are irrelevant because the Imac must receive only what is is transmitted in the 'G' range, 'N' class reception and hence the benefits of higher frequencies are not available. The only solution is to have 'N' class devices through out the network, otherwise everything reverts to the 'G' class range of lower frequencies. The solution to extend the frequency range of the network is to upgrade ethernet cards and base stations, so that 'N' class frequency transmission can be utilized.
The network will work with 'G' and 'N' devices but the network is only as good as the lower class device of transmission and reception.
I would start by getting an extreme network airport base station and then experimenting with different channels at a midpoint power transmission. The best frequency would be one which delivers the most power at a set power transmission level (signal strength). The higher the frequency the greater the penetration through walls, beams, people, dogs, cats, pipes, tabletops....:). I would then experiment with the power levels for the range which you want to cover, most likely just your home and not your entire neighborhood.
In my house I use channel 6 and power level 5 from a 2wire gateway/router, which is in the G extreme class range. I have always used channel 6 but I have tried power levels 3, 4 and 5. The biggest interference variable being weather and cordless phones. The cordless phones operate in the 2.4 GHZ range and the 900 MHZ range. The phone directly above my router is a 900MHZ phone and it never interferes with the 2.4 GHZ wifi network. I think the worst phone to have with a G class network are the 5.4GHZ phones because they actually use some of the same wireless bandwidth. A 'N' class network would probably be a better choice if you want to use a 5.4GHZ phone system.
good luck