On a related note I’ve found that I can get minor skin burns from the FlightAware external antenna metal bracket. The antenna, preamp, Pro Stick Plus and RPi are all indoors on a windowsill. The antenna is mounted, via its bracket, on a small wooden rod on the window sill.
The RPi PSU is the official one and this is a switched mode supply with a floating ground which produces the familiar tingling effect when touching the metal case or connectors, caused by microamp earth coupling. The presence of the preamp or not makes no difference.
The metal bracket on the antenna is connected to the same via the coax’s braid, but something about the antenna construction appears to cause a high voltage at the bracket such that in the dark, if I brush it with a metal object, tiny sparks are visible. If I brush the bracket with a finger, I feel that familiar tingle but any slight cut on the skin gets a burning sensation, presumably caused by the high voltage at microamps. Doing the same at the RPi end of the coax and the tingle is there but never any sparks or that burning sensation.
Anyone else experience this? Also, if this is ever mounted outdoors then I presume the possibility of corrosion due to the presence of this voltage and atmospherics acting as an electroyte becomes a reality.