How to read iw allowed interface lists?

I wanted to set up promiscuous Wi-Fi monitoring into Wireshark. Tried to do it like I used to with iwconfig, but this system sets me back to managed as soon as I bring the interface back up. I see online posts saying iw can add a monitor interface alongside the managed connection, so you can keep your internet alive while monitoring. Would be great, but: [loren@Gazp9 ~]$ iw dev wlp3s0 interface add mon0 type monitor command failed: Operation not permitted (-1) [loren@Gazp9 ~]$ iw phy wlp3s0 interface add mon0 type monitor command failed: No such file or directory (-2) [loren@Gazp9 ~]$ iw phy Wiphy phy0 [loren@Gazp9 ~]$ iw phy phy0 interface add mon0 type monitor command failed: Operation not permitted (-1) (That's Antergos 4.19.8-arch1-1-ARCH, if it matters.) So I dug deeper, including https://unix.stackexchange.com/questions/401464/deciphering-the-output-of-iw-list-valid-interface-combinations here. But I'm still not sure if this means there is no hope of adding the monitor interface. Here are excerpts from my "iw phy" command response: phy0 Supported interface modes: * IBSS * managed * AP * AP/VLAN * monitor * P2P-client * P2P-GO * P2P-device Supported commands: * new_interface (nothing about add interface) software interface modes (can always be added): * AP/VLAN * monitor valid interface combinations: * #{ managed } sudo iw dev wlan1 station get and > sudo iw dev wlan0 set power_save on show the use of sudo? None of the "add" commands show it: > iw dev wlan0 interface add fish0 type monitor flags none But this is intellectual curiosity. I'm happy to have a working monitor and get on with the real project.