I briefly looked at getting a similar product as I have no signal at my property.From what I was told it only works to improve/boost the current signal up to its current level.
When in a house or a building the outside signal gets shielded from getting to your phone, so the device spreads the current signal throughout the house or business to reach your phone.
I was told it wouldn't boost the signal coming from the tower any more than it is.

Here is a quote from the website FAQ...

Quote:
How can I tell if it will help extend coverage in my home or office?

You can run a simple test. If you can place a call outside your home or office, the Wireless Extender unit will help you by boosting the signal inside the building. If there is no signal outside, this unit will not give you an improvement in coverage. Remember, we can only help improve your signal strength if you have enough of a signal outside to place a call.