Router Details: Linksys WRT1900ACS V2, OpenWrt LEDE 17.01.5 installed and reset to default values
Following the preliminary instructions given near the top of the page --
PuTTY returns --
(Here I assume that the bullet notes such as "Remove the disable 1 option from the wireless configuration" refer to the commands listed above and are not instructions of further things to do before executing iwlist scan.)
There is also no need to put the device in station mode anymore nowadays, a mere iwinfo radio0 scan should suffice, regardless of the state the radio is in.