I decided I wanted to check a out if those apps that claim to boost the Phantom's signal actually work. It seemed like when I used them I sometimes had less drop-outs. So here is what I found.
This is my Phantom at home with no boosted signal:



Here it is boosted:


While the extender power didn't change much the Phantom's power output did. The Phantom is the yellow trace with the asterisk on top and no name. Also I changed the channel the Phantom and the extender were communicating on. It originally was on channel 1. There are a couple of other access points on that channel. Channel 9 was clear so I set it to that. I suggest you check the channel traffic if you are flying in a populated area.

So what software were you using?

I have tried a couple of different ones, Range Booster, Vision+ Utility. The channel was changed with FPV Booster.  It also allows you to add a WPA password. Now having said that even though I have flown with these I am not endorsing any of these programs (i'e. use at your own risk).

Also I changed the channel the Phantom and the extender -- How ??

FPV Booster app