Could it be rf-noise entering the analog preamp in tbe mic? When touching the antenna you divert some of the rf so it may not induce noise into the analog circuit.
I finished my firmware updates. 12 mics and I gotta say it feels weird updating the transmitters using IR, but it worked. Still gotta do the guitar and bass.
Noise was still there so I played with a few units (Crown CM311) and found that the noise was induced when the inline preamp (I think that's what it is) was near or touching the body pack. As I've been using these mics for years I'm going to assume that it's another QC problem since AKG bought them. I'm going to have to find another mic. 8 of them and so far I've yet to find anything that works as well as the Crown.
Now that I think about it, could be the wiring in the TA4F connector. I'll have to check that tonight.