FON Boards

primus1024 · Fonero C Joined: 13 Mar 2006 Posts: 118

I think the limit is put on EIRP (Effective Isotropic Radiated Power) which is the power antenna is transmiting and not on power of transmiter. So if you have very good antenna you have to limit the transmiter power. Well I may be wrong as I'm not from US ...
With your idea you would also use all non overlaping channels which is not very nice to your neighbours. They might also like to use their wlan Wink

AustinTX · Posted: Tue Apr 04, 2006 02:32 Post subject:

primus1024 · Fonero C Joined: 13 Mar 2006 Posts: 118

The channels used by wifi routers are overlapping.
Only 3 channels don't overlap (1, 6, 11).

You can use other channels but if anyone near you is using channel that overlaps with yours, neither of you will get full speed that is possible otherwise.

Crash · Fonero Joined: 29 Mar 2006 Posts: 22

It seems everyone in my neighborhood is running on channel 6, which is usually the default for most routers. I have two access points in my house; one for Fon, and a private network for my own equipment. One runs on channel 1, the other on 11.

AustinTX · Posted: Tue Apr 04, 2006 04:17 Post subject:

This chart may help you visualize how wifi channels overlap:

Do not think of each channel as a frequency. Each channel is a range of frequencies of the same width, but which start at different absolute frequencies. It is safe to pick any channel which does not share any frequencies with another channel in use in the same area. It is inaccurate to state that only three channels do not overlap. You can see that if either channel 1 or 11 are allready in use, there are as many as 6 different channels to choose from that don't overlap. Ch 1, 6 and 11 are the favored choices because it gives you the widest range with the least chance of interfering with other channels. You might use channels 2-5 if there is noone using either channel 1 or 6-7-8-9, but something is causing radio interference at the low end of 1 or the high end of 6. Cool

BTW: the channels on cordless phones do not follow this convention, nor do their channels correspond with wifi channels in any way, even if they are laid out somewhere in the "2.4Ghz band". That is to say, do not bother switching your cordless phone to "channel 2" to avoid interfering with your wifi on channel 1. It uses an entirely different definition of what a "channel" is. This is something a friend of mine still does not understand. Laughing

_________________
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Linus || WRT54GL @ 228Mhz || DD-WRT v24 Beta (01/15/07) std
My background: ISP NOC Tech, DSL - ISDN - Dialup - Web Hosting
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Abasota · Posted: Tue Apr 04, 2006 14:06 Post subject:

The statement:

primus1024 · Fonero C Joined: 13 Mar 2006 Posts: 118

I see this topic became quite active Smile

So here it goes:

1. @AustinTX: at the time of my reply I didn't see the map with sectors you posted (it was 2:44 in the morning ... I must have been blind or something), sorry about it, and of course, you are wright, you wouldn't use all channels and your neighbours would be quite pleased Smile

Abasota · Posted: Tue Apr 04, 2006 15:29 Post subject:

Primus1024,

I see your point now. I agree

Crash · Fonero Joined: 29 Mar 2006 Posts: 22

Since this thread seems to have taken on new meaning, and you guys seem so knowledagble about this channel thing, let me ask you this...

My Fon WRT54GL running on channel 1 is stacked on my non-Fon WRT54G v3.0 running on channel 11 (and both sit on top of a Vonage non-WiFi Linksys router). I understand these channels don't overlap, but are there any other issues that I should be concerned with as far as having the two WiFi routers so close to one another?

primus1024 · Fonero C Joined: 13 Mar 2006 Posts: 118

I had two wrt54g's one on top of the other and they were running quite hot. I suggest you check how hot do they get and that they are not on direct sunlight. The heat might be a problem in summer and may cause disconnects ...
I did not notice any difference of quallity of the signal when they were stacked or approximatelly 1 meter apart (3 feet). I use different antenna than the one that came with router so that might make a difference ...

Crash · Fonero Joined: 29 Mar 2006 Posts: 22

Thanks for the info Primus...

Heat was an issue when I first stacked the WRT54G and my Vonage router, but that was resolved with a small fan that I have pointed at the routers. It hasn't been a problem recently.

AustinTX · Posted: Tue Apr 04, 2006 17:00 Post subject:

I found a large, flat heat sink to place on my router cpu, just because I had it around and thought it was cool. Then I was suprised by how hot the heat sink got. So I have added a little fan now, too. Cool

I'm beginning to wonder if it is really a good idea to install this router outdoors since it runs so hot to begin with. I hoisted it up into my tree this past weekend to see what kind of range I got.... I could see the SSID for a couple of blocks away, but lost the connection and could not reconnect when only 2 houses away on either side. Sad

_________________
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Linus || WRT54GL @ 228Mhz || DD-WRT v24 Beta (01/15/07) std
My background: ISP NOC Tech, DSL - ISDN - Dialup - Web Hosting
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Abasota · Posted: Thu Apr 06, 2006 15:25 Post subject:

On behalf of the European FONners I would like to point out how ITU Region 1 differs to Region 2 (America). In Europe ISM bands are not channelized, despite all commercial devices being sold here are channelized. Specifically, Wifi devices have 14 channels as the WRT54G does. 11 of which can be used in America, 13 in France, and 14 in the rest of Europe (channel 14 cannot be used in France).

Therefore channel useage in Europe has more valid non-overlapping combinations than the figure below (posted earlier by AustinTX)

European sites having:

3 routers have 4 non-overlapping combinations: channels 1, 6 and 11, or 2, 7 and 12, or 3, 8 and 13, or 4, 9 and 14
2 routers have many multiple combinations: 1 and any channel between 6... and 14, 2 and any channel between 7 y 14, etc.

Recall the figure above refers to the American channel allocation only, no to the European.

AustinTX · Posted: Thu Apr 06, 2006 18:28 Post subject:

Here's a more complete chart of the channels and how they overlap. 1-11 are all that are allowed in the USA, 12-13 are also used in EU, and 14 is also used in Japan. Looking at the chart, notice that Ch 14 is not offset the same way as the other channels. This is not done just for illustration purposes here. Ch 14 starts on the same frequency that Ch 11 ends on, without the usual gap of 5 mhz, so that in Japan one can choose from FOUR different channels that (relatively) do not interfere with each other. Cool

_________________
Well, as Revolutions go, this one has certainly been revolting! Wink

Linus || WRT54GL @ 228Mhz || DD-WRT v24 Beta (01/15/07) std
My background: ISP NOC Tech, DSL - ISDN - Dialup - Web Hosting
[ El Fon Blog ][ RSS Feed ][ skype:elfonblog ][ gizmo:therealelfonblog ]

Abasota · Posted: Thu Apr 06, 2006 19:47 Post subject:

Thank you AustinTX for clarifying this.

Therefore European sites having:

3 routers have 9 non-overlapping combinations: channels 1, 6 and 11, (or 12 or 13) or 1, 7 and 12 (or 13), or 1, 8 and 13 or 2, 7 and 12 (or 13) or 3, 8 y 13
2 routers have many multiple combinations: 1 and any channel between 6... and 13, 2 and any channel between 7 y 13, etc.

AustinTX · Posted: Sat Apr 08, 2006 04:59 Post subject: Whoah, Hoss!

Continuing with the topic of beating dead horses, I thought i'd share a chart showing which frequencies are used for wifi by country:
Channel_Center Frequency____Frequency Range

So i'm thinking: poor Spain! Laughing

_________________
Well, as Revolutions go, this one has certainly been revolting! Wink

Linus || WRT54GL @ 228Mhz || DD-WRT v24 Beta (01/15/07) std
My background: ISP NOC Tech, DSL - ISDN - Dialup - Web Hosting
[ El Fon Blog ][ RSS Feed ][ skype:elfonblog ][ gizmo:therealelfonblog ]

Abasota · Posted: Mon Apr 10, 2006 12:02 Post subject: Re: Whoah, Hoss!

AustinTX · Posted: Mon Apr 10, 2006 17:32 Post subject: Re: Whoah, Hoss!

Ugh. I had deleted this entry but it came back!
_________________
Well, as Revolutions go, this one has certainly been revolting! Wink

Linus || WRT54GL @ 228Mhz || DD-WRT v24 Beta (01/15/07) std
My background: ISP NOC Tech, DSL - ISDN - Dialup - Web Hosting
[ El Fon Blog ][ RSS Feed ][ skype:elfonblog ][ gizmo:therealelfonblog ]

AustinTX · Posted: Mon Apr 10, 2006 17:52 Post subject: Re: Whoah, Hoss!

[quote="AustinTX"]

Abasota · Posted: Tue Apr 11, 2006 11:13 Post subject: Re: Whoah, Hoss!