https://forum.clockworkpi.com/t/how-to-disable-wifi-power-save-to-prevent-disconnects/933 /etc/network/if-up.d/powesave_off

powesave_off

#! /bin/sh

set -e

# Don't bother for loopback
if [ "$IFACE" = lo ]; then
        exit 0
fi

# Only run from ifup.
if [ "$MODE" != start ]; then
        exit 0
fi

# Only do it once (skip for inet6).
if [ "$ADDRFAM" != inet ]; then
        exit 0
fi

/sbin/iw dev "$IFACE" set power_save off

exit 0