Here is some alien technology: How Do Flying Saucers Do That?
The technology is similar to a microwave in your kitchen. They have an emitter that emits microwaves which are rotated very fast, like a helicopter's blades. The rotating field is disk shaped around the source, extending out from the craft for several hundred yards, and repels gravity fields. The speed of rotation and angle of attack steers the craft just like a helicopter, though quite a bit faster. This explains the anomalous effects on electrical systems, and the mild radiation effects. It is the rotating field itself that repulses or negates the earth's gravity (and any other gravity, for that matter), allowing the occupants to survive in 0-G what would otherwise smash a meat body.