Last Post: April 28, 2005:
In ETSI countries there are 13 channels available for use. The approved frequency range of operation is 2412-2472 Mhz.
It seems that portions of channel 1,2,12 and 13 are outside of the range.
What does this mean?
Are APs that use 1,2,12 and 13 penalized?
It's my understanding of the Standard that ETSI specifies operation from 2.4GHz to 2.4835GHz, and that the center frequency of channel 1 is 2.412GHz and the center frequency of channel 13 is 2.472GHz. Therefore the upper and lower channels operate within the specified frequency range.
Hi Sacim of Italy:
See IEEE 802.11 section 220.127.116.11 Number of operating channels
"The channel center frequencies and CHNL_ID numbers shall be as shown in Table 64. The FCC (US), IC (Canada), and ETSI (Europe) specify operation from 2.4 GHz to 2.4835 GHz. For MKK (Japan), operation is specified as 2.471 GHz to 2.497 GHz. France allows operation from 2.4465 GHz to 2.4835 GHz, and Spain allows operation from 2.445 GHz to 2.475 GHz.
"In a multiple cell network topology, overlapping and/or adjacent cells using different channels can operate simultaneously without interference if the distance between the center frequencies is at least 30 MHz. Channel 14 shall be designated specifically for operation in Japan."
Channel one is centered on 2412 MHz. Successive channel centers are every 5 MHz. All IEEE 802.11 2.4 GHz channels are centered plainly within the regulatory ranges. What is less plain is how the transmission spectral mask of any one channel overlaps adjacent channels. The official answer for channel separation "without interference" for the DSSS PHY is 30MHz and for the HR/DSSS and ERP PHYs is 25 MHz.
I hope this helps. Can you add your city to your forum profile? Thanks. /criss
If we have 13 full channels in ETSI countries, does that mean that we have more choice for non-overlapping channels? Instead of just 1-6-11 we can also choose 2-7-12 and 3-8-13?
Yes, or have even less overlap with 1-7-13.
I hope this helps. Thanks. /criss
very helpful, thank you.