On 10/14/20 7:21 PM, Jeff Liebermann wrote:
On Wed, 14 Oct 2020 00:25:08 -0700, Johann Beretta
wrote:

On 10/6/20 4:35 PM, Jeff Liebermann wrote:

To get some decent speeds, 5GHz
instead of 2.4GHz.

Generally speaking, yes. Practically speaking you can do several
hundred mbps over a 2.4 link. You just need to widen the channel.

While there are 2.4GHz routers available that have a 40MHz channel
bandwidth setting, I prefer not to use it because it reduces the
available bandwidth to other users on 2.4GHz. If one is sufficiently
clueless to use a 40 MHz channel set to CH6, it will effectively
trash most of the 2.4GHz band. Since Wi-Fi pollution can be
symmetrical, it also makes the receiver susceptible to more
interference. Stay with 20MHz channel bandwidth on 2.4GHz.

In dense environments, I agree. In rural areas, interference may not be
a factor. In extremely rural areas, interference PROBABLY won't be a
factor.



On the other foot, the minimum channel bandwidth on 5GHz is 40MHz
(depending on channel selected) with an option to use 80MHz or 160MHz
for 802.11AC and AX (Wi-Fi 6).
https://en.wikipedia.org/wiki/List_of_WLAN_channels#5_GHz_or_5.9_GHz_(802.11a/h/j/n/ac/ax)
With 1024-QAM, 802.11AX can theoretically do 1.2Gbits/sec in a 160MHz
channel. Your mileage will certainly be less.


No.. The minimum 5GHz channel bandwidth is 5MHz. Not sure where you are
coming up with 40MHz as a minimum. Out of several dozen transmitters, I
only have two set to 40MHz (backhauls). The rest are set to 20MHz with a
couple at 10Mhz.

My gear (Ubiquiti) supports 5, 8, 10, 20, 30, 40, 50, 80 Mhz wide channels.


Anyway, the performance limiting factor is usually interference from
co-channel users and noise sources. You could have all the bandwidth
in the world, the most efficient modulation scheme, maximum legal RF
power, and still not be able to communicate very well or far if there
is an interference source nearby. In other words, one needs to do
more than just "widen the channel".


Once again, sometimes. Sometimes ALL you need to do is widen the channel.