Total posts : 45366
Referring to your sig, using an electrical outlet ground might be one of those ideas that suck 🙂 If the hum is a fairly low frequency, constant hummmmmm, you might be picking up the 60 Hz of the AC wiring. The reason you only hear it when there’s no music might be because the modulation section of your transmitter only modulates the hum when there’s no other audio signal to work with. If the outlet ground is the source, you could remove your audio chain entrely and still get the hummmmmmm.
A good ground is hard to find, but an AC outlet ground isn’t even a real RF ground option, so you won’t be giving up anything if you just pull that.
A proper ground is ideal, but any true earth connection is better than what you’re working with now. Metal water pipe, metal fence post, metal stair railing, a whole bunch of wire laying on the floor of the garage, all of these are far better than an outlet ground. I have soldered a short length of wire to a 36″ X 1/8″ solid brass hobby and craft rod (hardware store, $2.00) and drove that into the garden outside my apartment window for a great start on a ground, not ideal, but far better than an outlet. I think, strictly speaking, electrical code and all that, you’re not even supposed to do that with an outlet ground…