WiFi issues, can get it to work

I added a USB antenna to my MacBook Pro (Retina, Mid 2012). It made no difference. I am still dropping the wifi - it says wifi:on 5 seconds later it says wifi:looking for networks

I have done a lot of things. Changed ISP, tried Airport Express Extreme, changed settings, turned off Bluetooth and still get wifi:on wifi:waiting for networks toggles ever 5 seconds. Adding a DHCP stopped the ping from failing but still wifi messages. Very evasive.