The Belkin Tunecast2 is a nicely designed piece of technology, superior to other devices of its sort due to its ability to tune to any FM frequency that you desire. The device is only limited by its range of operation. Before I modded my Tunecast2, it would operate efficiently at a distance of up to about 20-30 feet. After the mod, I was able to rebroadcast audio clearly without interference througout my entire house and even outside the house! Link.
HOW TO modify the Belkin Tunecast2