Will a repeater work for me? Do a field test.
You will use your mobile phone to test the signal quality outside your house.
Step Two
Make sure you are not connected to WIFI. (Switch off WIFI on your phone)
Step Three
Take a note of the signal bars and the symbol in the status bar of your phone.(see image below)
Learn More
If you want to know precisely what frequency your Samsung phone is using, read this article.
If you want to know precisely what frequency your iphone is using, read this article.