Multiple wifi routers - what channel numbers?

I have read somewhere that one cannot simply set say ch 11 ch 5 and ch
7 for three of them; the channels overlap in some strange way.

Is this true, and if so how can I determine which channels to set?

"Peter" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
>I have read somewhere that one cannot simply set say ch 11 ch 5 and ch
> 7 for three of them; the channels overlap in some strange way.
>
> Is this true, and if so how can I determine which channels to set?
>

For complete tollerance, use channels 1, 6 and 11. This will give you three
"cells" in which to work. Although I have seen, and have used different wifi
networks that overlap.

"Peter" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
>I have read somewhere that one cannot simply set say ch 11 ch 5 and ch
> 7 for three of them; the channels overlap in some strange way.

The receivers have very limited selectivity so strong local signals will
affect them even if they are supposedly tuned to different channels.
Make sure there is a reasonable gap between them.
It gets more difficult if you have other local wifi networks to dodge.


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On Wed, 4 Oct 2006, Gordon Hudson wrote:

> The receivers have very limited selectivity so strong local signals will
> affect them even if they are supposedly tuned to different channels.
> Make sure there is a reasonable gap between them.

Quite right.

> It gets more difficult if you have other local wifi networks to dodge.

Most users have no idea that their wireless base comes configured to
use only the USA-assigned channels 1-11. In Europe, we can use 1-13
(ETSI). So switch your box to ETSI channel assignments and use ch.
13. No promises, but it usually works for me. It's a bit close to ch
11, though, if that happens to be in use locally.

On 2006-10-04, Peter <(E-Mail Removed)> wrote:
> I have read somewhere that one cannot simply set say ch 11 ch 5 and ch
> 7 for three of them; the channels overlap in some strange way.
>
> Is this true, and if so how can I determine which channels to set?

The bandwidth of the transmitted WiFi signal is actually 5 channels
wide, so channels less than 5 apart will overlap. To set 3 access
points to non-overlapping spectrum you'd pick channels that are
separated by at least 5, like 1-6-11, or 1-7-13, or something.

This channel selection isn't fundamentally necessary for it to
work, however. Even if you set them all to the same channel
you'll likely still have fine results, certainly if your
computers always attach to the closest access point, since
the APs are still separated by code division. The issue is that
the "signal" from one AP is "noise" with respect to the
other APs to the extent that their channels overlap, so
minimizing that overlap between adjacent APs will improve
their signal-to-noise ratio, and hence improve things like
connection speed.

So you don't need to worry a whole lot about channel selection,
but minimizing the channel overlap of an AP with its closest
neighbours will improve performance.

Dennis Ferguson