My question is not really ham related but I'm hoping someone can offer some advice on my problem or if not, maybe you can direct me to a more appropriate group/forum.

I'm troubleshooting a bad reception issue. I bought a Magnum Dynalab ST 2 FM antenna, put it up on the tower in the back yard connected it to a NAD 7220 PE receiver via RG 59 cable and a 75 to 300 Ohm transformer and all I hear is what I can best describe as a howl.
The strange thing is I accidentally discovered that with the cable's terminal wires are near, but not connected to the receiver I get a strong, clear signal from a local FM transmitter but the signal broadcasted by a Whole House FM transmitter connected to a source in the house produces very bad reception in the garage woodshop less than 100 feet away. The transmitter should be good for nearly 1/4 mile.
I'm sure it's not an issue with the transmitter as the FM section on a portable MP3 player picks up the signal fine all over the back yard.

Unfortunatley I don't have another FM receiver to experiment with and I'm starting to wonder if my receiver need servicing.
I'd be very appreciative if anyone could give me some direction.

Thanks for reading.