When using the 2.4GHz broadcasting radio you should generally use a channel bandwidth block 20MHz wide. This is because there are more non-overlapping channels available when using 20MHz (as opposed to 40MHz) which means there is less likelihood of congestion or clashing channels. You can also use 40MHz on the 2.4GHz broadcasting radio. Z = Bandwidth 2, 4, 8 (2 = 20Mhz, 4=40Mhz, 8=80Mhz) c = b for Beamform, s for STBC, - none s = Guard Interval, indicates Short guard interval applicable over LGI (Long guard interval) If you use 40 MHz channel the max data rate will be 270 Mbps and 300 Mbps for long and short guard interval respectively. 20MHz channel 800ns GI 130Mbps. 20Mhz channel 400ns GI 144Mbps. 40MHz channel 800ns GI 270Mbps. 40Mhz channel 400ns GI 300Mbps. Smaller guard interval more bandwidth. Also if you double the channel width you get slightly more throughput than simply doubling the data rate as the bit where the two channels join is used more efficiently. 1 Answer. It's strictly an increase in bandwidth. Unfortunately, the 2.4Ghz band is saturated and running with a 40Mhz bandwidth is likely to just make you more susceptible to interference and provide even worse performance. There is no change in signal strength or distance. I believe an increase in interference will affect the received The 20MHz channel width is recommended for long distance. connections. 40MHz Channel width. The 40MHz or 40MHz turbo channel width, transmits over wide frequency spectrum, giving room for speed but at a high possibility of signal fluctuations caused by interference. Config your capture device with the appropriate iw command. Validate that you are seeing traffic you expect, like QoS Data, etc, from the client. The radiotap header will tell you if it is 40MHz or 20MHz bandwidth. If it doesn't work, keep trying: change iw commands, move channels, get a different capture device, etc. 2x2 40 MHz: 300 Mbps: 2 TX 2 RX: 3x3 20 MHz: 216.7 Mbps: 3 TX 3 RX: 3x3 40 MHz: 450 Mbps: 3 TX 3 RX: 802.11g. Released in 2003. Data rates with varying modulation types: 6, 9, 12, 18, 24, 36, 48 and 54 Mbps; can revert to 1, 2, 5.5, and 11 Mbps using DSSS and CCK. When the OFDM PHY was introduced to 802.11, the channel bandwidth was 20MHz with later amendments adding support for 5 and 10MHz bandwidths. The 802.11n amendment added support for an optional 40MHz channel. 802.11ac will include support for 80MHz bandwidth as well as an optional 160MHz bandwidth. The 11ac QCXpvXa.