Hi!
How to choose to work only with 80 MHz in a Netmetal link
You can't. Basic channel width in 802.11 is 20MHz ... and standard only allows to use multiple adjacent channels "in a bundle". So you can configure your AP as 20/40/80mhz ... and all compliant stations will use 80mhz ... but it is possible that some stations will choose to use only 40mhz or even only 20mhz.
Gracias!!