Dog GPS

If all goes according to plan, my husband and myself will be buying a nice 55 acre property shortly. This is where we will retire in about five years although we will of course be spending long weekends there before retirement. We have three dogs who have either been in our fenced back yard or on a leash. I'm especially worried about our one year old standard poodle wondering off in search of good smells. I've been researching dog gps systems and believe I need to stay away from any one that requires a cell signal since that service is not reliable where we will be moving. I found one that may work and was wondering if anyway has any experience using it:

http://www.amazon.com/Marco-Polo-Monitoring-Tracking-Locating/dp/B008MG5GRQ/ref=sr_1_1?s=pet-supplies&ie=UTF8&qid=1400674055&sr=1-1

thanks,