With a 5.8 Ghz WLAN device, operating in the upper UNIII band of 5745-5825 MHz…
Is it required that, if the device is using a standard 20 MHz-wide 802.11 channel, that you can only be centered on the pre-defined frequencies of ch149 (5745 MHz), ch153 (5765 MHz), ch157 (5785 MHz), ch161 (5805 MHz) or ISM Band ch165 (5825 MHz)?
Is it not allowed to set the center of the 20 MHz-wide operation channel to, say, ch155 (5775 MHz)?
I would think that as long as you are within the 5745-5825 MHz band, it shouldn't matter what the center frequency is.
I'm being told that with a 20 MHz device, you can only use those 5 pre-defined channels as their center frequency. What about devices capable of 10 MHz and 5 MHz wide channel use?
Thanks in advance.
Best Answer
If your equipment supports it, you can set it to Channel 155, however, this is not desirable, as you will get interference from the two adjacent channels. The recommendations are just that, recommendations. There are no requirements in FCC 15.245 or 15.247 (ISM regulations) for a specific channel, as long as you are not near the band's edge.
Edit: Following Dave's comment: There are the U-NII (15.407) rules which differ slightly from the 15.247 rules, but there is no specific channel requirements. If the equipment supports it, any frequency inside the band can be used. As for narrow band FHSS transmissions, there is a different set of requirements which applies to them.