Wifi Channels In Thailand

[fanciman]

Which are the usual channels used in Thailand for wifi?

Which frequencies? (20MHz/40MHz , both, neither...)

If one's signal is consumed by a nearby network, which channel would you suggest using?

[Prasert]

802.11a 5GHz is not allowed

802.11b frequency in GHz:

2.412 (1)

2.417 (2)

2.422 (3)

2.427 (4)

2.432 (5)

2.437 (6)

2.442 (7)

2.447 (8)

2.452 (9)

2.457 (10)

2.462 (11)

2.467 (12)

2.472 (13)

Each wifi connection requires a bandwidth of 4 channels - so only 4 non-overlapping channels exist: 1, 5 ,9 and 13. If you're experiencing problems, check on which channel nearby accesspoints operate and choose another (non-overlapping) one.

If someone is using a 802.11n (the pre-Wimax disaster), you're having bad luck - these accesspoints use 2 or 3 bands to double throughput.

Edited February 15, 2007 by Prasert

[fanciman]

802.11a 5GHz is not allowed

802.11b frequency in GHz:

2.412 (1)

2.417 (2)

2.422 (3)

2.427 (4)

2.432 (5)

2.437 (6)

2.442 (7)

2.447 (8)

2.452 (9)

2.457 (10)

2.462 (11)

2.467 (12)

2.472 (13)

Each wifi connection requires a bandwidth of 4 channels - so only 4 non-overlapping channels exist: 1, 5 ,9 and 13. If you're experiencing problems, check on which channel nearby accesspoints operate and choose another (non-overlapping) one.

If someone is using a 802.11n (the pre-Wimax disaster), you're having bad luck - these accesspoints use 2 or 3 bands to double throughput.

OK, so if they are using a non-standard channel, like channel 4, 6, 7, 10 what would one do?

What would be an indicator on wirelessmon that they are using 802.11n?

Is there usually a big fight to get the channel at the middle of the numbers? (Because 1 can't overlap negative 1, negative 2...)

If they use the wirless 802.11n, that means they take up 8 channels, right? going from, eg. From 1 to 8 and 8 to 16? And all the channels are consumed? omg!

Thank you! This is quite a big problem, and has been troubling some time.

[Prasert]

If you're having a lot of accesspoints nearby, the 2.4GHz band might be full.

Another rule for WiFi is dat the maximum amount of radiated power (EIRP) may not exceed 20dBm, which is about equal to 100mW.

This way, the signal will not travel very far and your accesspoint, which is nearer to you (I assume) will have a stronger signal. Not much you can do about all this but something to keep in mind.

Now, when you scan the air (google on NetStumbler) and see that a nearby accesspoint is operating on channel 6, this means that the 3 next channels are occupied as well. If 10, 11, 12 and 13 are available, choose 10.

In real life, no one will actually think about this. Recently we added another hotspit in an area where 3 other shops had WiFi (not public). Since we managed their networks as well, we simply changed the channels on all accesspoints so neither would be interfering with each other (channels used: 1 - 5 - 9 - 13).

If you encounter anything like this, talk with them and agree on channel usage. If the owners are Thai, simply forget about this too (they won't and can't understand the concept).

802.11n. Fortunately I haven't seen these in real life yet, but I saw some accesspoints at suvarnabhumi and looked at the specs. The technology used is still a draft (pre-802.11n - so not a standard!) and it looks promising, but you're actually using the whole spectrum for yourself. Place 3 or 4 of these accesspoints within eachothers range and it simply won't work anymore.

[monty]

Another annoying interference generator are the accesspoints offering "dual throughput" like 22 mbps for 801.11b or 104 mbps for a 801.11g accesspoint.

They achieve the extra throughput by using two of the 4 non overlapping channels simultabiously...

Another one are these "boosters" they sell, boosting the output way beyond the allowed EIRP, they'll blow any other legal signal simply away...