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Asterix
Premium
join:2002-09-18
Nazareth, PA
kudos:3
Reviews:
·RCN CABLE

20/40Mhz ???

I am planning to get the dual band channel bonding wireless router from DLink, DIR-855, once its launched. I already have a Broadcom Dell 1500 dual band wireless card in my laptop.
When I look at the option in the wireless card there are so many channels in there now that its really tough for me to understand what all these are. It used to be simpler in 11b/g days where there were just 11 channels and I knew 6,11 & 1 were to best of the lot with the least interference, if only I could find other wireless not already on that channel. But now this card shows 3 options for almost every other channel, like 6(20Mhz)..6(40Mhz-U)..6(40Mhz-L) and other Capability options are 11a(20Mhz/40Mhz)11g(20Mhz/40Mhz)..11a(20Mhz/40Mhz)11g(20Mhz)..etc

I am pretty confused and want to learn more on how I can used these options to best suit my requirements.

Please can anyone explain or guide me to a link when I can understand these settings and what these bands and frequencies are?
--
The art of flying is to throw yourself at the ground and miss


stevech0

join:2006-09-17
San Diego, CA

2 edits

My unsolicited advice: think twice before purchasing D-Link.

the 40MHz options in 11g/n are bad news. Doing so, you use up 2/3 of the entire WiFi band. That's OK if you live in the desert.

Indeed, most products refuse to run in the 40MHz mode if there are ANY 20MHz (11b/g pre-N) WiFi systems detected in the neighborhood. I suppose there's a setting for you to rudely overrule this policy.

The dual band product you mention would use 802.11a as the second band. That's at 5.8GHz rather than 2.4GHz where most WiFi is. There are more channels in the 5.8GHz band and it's less congested, so far. I don't know if products will channel-bond in the 5.8GHz 11a band. Of course, you need client devices that support 11a and those are few and far between, and fewer yet that might do 40MHz bonding in 5.8GHz. But this is coming, as more people try to cram video on wireless - a real problem in urban areas.

As at 2.4GHz, cordless phones can be an interference problem. And there are plenty of 5.8Ghz cordless phones now.



Anav
Sarcastic Llama? Naw, Just Acerbic
Premium
join:2001-07-16
Dartmouth, NS
kudos:5
reply to Asterix

I will follow up stevehawaiifive0 by simply stating that if you provide us with what functionality (NOT THE SOLUTION) your trying to achieve, then we can really help you get there with known existing solutions. Believe half of what you read about networking equipment from the vendor and from any sites that get paid by vendors to advertise "review" the product.



Asterix
Premium
join:2002-09-18
Nazareth, PA
kudos:3
Reviews:
·RCN CABLE

1)I want to understand the new settings in 11n and what they mean.
2)Also would like to know the differences among them and which ones can prove beneficial to me to get the most bandwidth and speeds out of 11n.
3)Current 11n speeds are 270/300Mbps, I want to know how to achieve this speed with the least interference.

Thanks!
--
The art of flying is to throw yourself at the ground and miss


stevech0

join:2006-09-17
San Diego, CA

1 edit
reply to Asterix

Least interference from neighbors' WiFi: use 5.8GHz.
pair bonding of channels in that band which is called 802.11a, but when using 40MHz, it's kind of like 11na (!)



Asterix
Premium
join:2002-09-18
Nazareth, PA
kudos:3

so is 20Mhz 11b/g?


stevech0

join:2006-09-17
San Diego, CA

3 edits
reply to Asterix

No. 20MHz is in 802.11b/g and 802.11a.

20MHz is a channel width. Bandwidth. Wider = more speed.

802.11b/g are standard at 20MHz bandwidth per channel.
802.11b/g channels are in the 2.4GHz band and always 20MHz.

802.11a channels are more numerous and are in the 5.8GHz band. The are standard at 20MHz.

40MHz bandwidth in 802.11n, if achievable as I dscussed above, about doubles the speed/capacity. 802.11n is mostly focused on the 2.4GHz band.

Either 2.4GHz or 5.8GHz can accomodate 20 and 40MHz bandwidth if the product implments all four combinations.

Since there are more channels and less usage, the 5.8GHz band is the best place to try 40MHz. This band is known as 802.11a.

802.11n is most commonly in the 2.4GHz band.

A very few products are now capable of 40MHz on 5.8GHz under the 802.11 standards.
Some may be dual-band but may operate 20MHz on 5.8GHz and 20/40MHz in 2.4GHz.

Use of 40MHz is imprudent at 2.4GHz and is an immature product technology at 5.8GHz at this time.



Asterix
Premium
join:2002-09-18
Nazareth, PA
kudos:3

Excellent. This is great information.

Also which channels in 5.8Ghz band are the best ones to use. For 11b/g we try to get 6,11 or 1.
--
The art of flying is to throw yourself at the ground and miss


stevech0

join:2006-09-17
San Diego, CA
reply to Asterix

channels in 11a.. I don't know. Some of the lower channels are 10MHz apart suggesting that you need to use every other one. But the mid/higher channels have different spacing. And supposedly, the max FCC legal power varies for lower/mid/upper channels. A WiFi device would restrict its power per these regulations. And the regulations in other countries.

so Googgle a bit on this.