I'm having intermittent satellite loss on the MkIV Nav in my 2004 X5 4.8iS. It was suggested to try a generic GPS antenna (from eBay) to see if it's the antenna or cable at fault but there appear to be different connectors available. Does anyone know if the correct connector is: mMCX, OSX, MCX or 2.5mm & if the BMW antenna is powered? Thanks from down under.