2.4GHz or 5.8GHz

maike14

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May 22, 2004
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OK. Here's my dilema. We're moving into a new house and will have both a wireless network (3PCs, a server and a couple of laptops) and a cordless phone system (base unit and 5 handsets). The phones are frequency hopping digital spread spectrum. I'm thinking it would be a good idea to have the phones and the network on different frequencies. So, 2.4 GHz for the phones and 802.11a for the network, or 5.8GHz for the phones and 802.11g for the network? I don't have any of this equipment yet so backward compatibility with 802.11b is not an issue. The house is single story and about 2400 square feet. I'll be able to locate the wireless router pretty centrally, so the furthest distance from the router to a PC should only be about 43 feet. I'm leaning towards 802.11a as I've read that the 5.8 GHz band is much "cleaner". Or would it be worth hedging my bets and getting a tri-band router like the D-Link DI-784. I believe this also uses the Altheros enhanced range technology, but I'm not sure if this applies to 802.11g or 802.11a? Any opinions, information and suggestions would be most welcome.

thanks
Mike
 

kwebb

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The atheros chipset doesn't enhance range though the range for .11a equipment, of which Atheros is about the only player these days, has overcome some of the early distance issues of early .11a gear. .11a is a niche market, predominately catering to enterprise level consumers. In other words AP and client devices will generally cost more, and provide slightly less overall bandwidth capability than comparable .11g 54 mb equipment. You sound like you already have the phone but you weren't clear on that completely. What do you have in place so far?

CCNA, MCSE, A+, Cisco Certified Wireless Field Engineer
 

maike14

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I don't have the phones yet, but all the brands I've looked at that support multiple handsets seem to use frequency hopping spread spectrum. Of the 5.8GHz, some like VTech and AT&T actually use both 5.8GHz (base to handset) and 2.4GHz (handset to base), although you have to read the very fine print to discover this :). I assume I should avoid these? I saw something about 5.8GHz interference problems being easier to fix because "802.11a enjoys the luxury of 12 independent, non-overlapping channels", which I didn't really quite understand. Does this mean a frequency hopping spread spectrum phone doesn't use these 11 channels? Do similar channels exist in the 2.4GHz spectrum?
Mike
 

kwebb

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Frequency hopping does what the name implies and jumps all over the band. With frequency hopping devices in the air you can't really avoid them with changing the channels on direct sequence devices, ie. 802.11a, b, and g. .11a has 8 non overlapping channels while .11b and g have 4, and actually you can adjust with 4 as they only overlap slightly. Really depends on proximity as to whether you can use 3 of 4. With frequency hopping phones I wouldn't worry too much about overlapping frequencies and just stay away from the WLAN with the phones, meaning go 5.8 phones and 2.4 LAN gear, or vice versa.

CCNA, MCSE, A+, Cisco Certified Wireless Field Engineer
 

maike14

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May 22, 2004
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Thanks for the explanaton and help. It looks like it will be cheaper using the 2.4GHz phones and 802.11a. While the 802.11a gear is more expensive than 802.11g, the 5.8GHz phones are even more expensive than the 2.4GHz.

Mike
 

peartree

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It may be cheaper to do it that way, maybe, but a real question that only you can answer- will the range you need be available to you with 802.11a? Add on to that the other questions I don't see. Are you planning on running ALL the computers in the house on the wireless network OR only a laptop? You have to keep in mind the bandwidth limits of wireless networking and decide whether the bandwidth used between your desktop systems will choke the limited wireless link. If you're constantly going to be transferring large files or streaming video, then Wi-Fi doesn't make sense. You'd be much better off, in that case, to go with wired gigabit Ethernet between the desktops. After all, there are no wireless routers for home use that have gigabit Ethernet ports.

You may have already made your decision and your purchase, but I'd be interested in hearing the answers anyway.





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