Budget FM Transmitter help

[Apache Lights 10]

I'm trying to make a simple fm transmitter out of junk around my house. I have a car fm transmitter and a set of rabbit ears that I've turned into a dipole antenna. The good news is it kinda works, the bad news is it uses a AAA battery that will be extremely difficult to get to when the whole thing comes together.

Because it was intended to be used in a car I have a 12V cord for it and found a 12V power adapter to power the cord.

When I tested it there is a strange humming and I'm getting nearly 3V out of the cord, I would have thought it should be 1.5V or close.

The adapter is a DC 12V 200mA. Any help would be greatly appreciated.

P.S. If I spend another dollar on my display this year I won't have time to put up lights.

I'll be too busy sighning divorce papers. Thanks again.

[excue2 10]

I used a Schosche FM trans for a car last year and it worked great. I tried to use a power supply with it but I got the hum. I went through 2 AAA`s every other night. I just bought the big cheap packs and they worked great. My range was almost 1/4 mi from my house. I had mine tied into a splitter coming off the speaker output of my computer and i think that the wire acted as an antenna. I am running the same this year. I will upgrade next year i think. Have you tried yours with it plugged in to your computer and running off batteries to see what kinda range you have?