I had a similar 'buzz' when I touched my satellite tripod(metal) when setting it up one day. I was 'drycamping' but using a neighboring business's 110 outlet with my 50a to 30a to 110v adaptors from the coach to keep my batteries trickle charged. Apparently the sat receiver sends voltage out to the sat dish(duh!)...
I found that the extension cord that I was using had the ground prong missing on one end.
I replaced the extension cord with a new grounded set and the 'buzz' went away.
The Turners 2014 Thor Palazzo DP 33.3 35' Bunkhouse
BlueOx, '14 Ford Fiesta, DishHD, KingTailgater2, WifiRanger
50k+miles, 200+ parks, 47 states&Canada provinces, since Aug'14