You can search Wi-Fi extenders here and find a few different types.
I use the EnGenius brand. I just replaced my old EOC5611 model with the newer ENS202EXT model. There are a few other members that use the EnGenius units. They cost around $100 shipped.
You will also need to purchase a regular WiFi router like used in the home, a second hand one with security will do fine. Your tablets, laptops, cell phones... will connect to it.
The basic system requirement is that the WiFi extender should have an outside antenna or a combined unit (unit that has the antenna mounted on the unit and is mounted outside). A cat5 cable is run between the WiFi extender and the WiFi router inside your TT.
These units are good for 1.5 miles line of sight. These units enhance only the signal between the CG's AP and your unit.
Here is a link to my Wi-Fi diagram
If this link did not take, go to my albums and click on the Wi-Fi section.
To give you an idea of what this unit does, currently we are only 200 yards from the AP, with 8 TT's, and huge trees between us and the AP, logging on to the AP directly with the laptop, there is 1 bar for the connection, with signals that keep dropping (outside between TT,s). Using the ENS202EXT, I am inside the TT and we just finished watching a Netflix movie with no loss of connection. The people around me have given up, the good news is that I convinced the owner to move the AP to a closer pole.. now they just have to wait for the work to be done.
I need to update the diagram with the new unit I purchased.
2013 Jayco Eagle 284BHS
250Watt Grape Solar Panel, MorningStar MPPT 60 Charge Controller
1500 Watt Ramsond PSI, 2 Trojan T145 Batteries (260Ah)
2 - AirSight Wireless IP Cameras (used as rear view cameras)
EnGenius WI-FI extender, D-Link wireless (n) modem
MagicJack Internet Phone
2012 Ford F150XLT, EcoBoost w/3.73
157" Wheel base, HD Towing Package
Our Solar Album http://www.jaycoowners.com/album.php?albumid=329