Comment 76 for bug 1788997

For me ant_sel=0 "zero!" was the magic key. Took me a week of messing around until I realized one cannot only select 1 or 2 but also 0. Try out with these:

sudo modprobe -r rtl8723be
sudo modprobe rtl8723be ant_sel=0
iwlist scan | egrep -i 'ssid|quality'
sudo modprobe -r rtl8723be
sudo modprobe rtl8723be ant_sel=1
iwlist scan | egrep -i 'ssid|quality'
sudo modprobe -r rtl8723be
sudo modprobe rtl8723be ant_sel=2
iwlist scan | egrep -i 'ssid|quality'

http://forums.debian.net/viewtopic.php?f=5&t=140368&p=691244#p691244