A medical apparatus for programming and/or monitoring an implantable medical device over a radio-based wireless network comprising: - a programmer or monitoring device provided with input and/or output means for transmitting programming instructions to and/or receiving monitoring information from said implantable medical device; - at least two antenna devices (5a, 5b,..., 5n) operatively provided at different locations, wherein - said programmer or monitoring device is connected to said antenna devices (5a, 5b,..., 5n) and is provided for transmitting signals to and receiving signals from said implantable medical device via at least one of said antenna devices (5a, 5b,..., 5n), - each of said antenna devices (5a, 5b,..., 5n) is provided as a physically separated unit wirelessly connected to said programmer or monitoring device, to thereby allow for movements of said programmer or monitoring device relative said antenna devices (5a, 5b,..., 5n), - each of said antenna devices (5a, 5b,..., 5n) comprises at least one conductive radiating antenna element capable of emitting and receiving radio waves of orthogonal polarizations, and - a control unit provided - for measuring a signal quality parameter of signals received from said implantable medical device by each of said antenna devices (5a, 5b,..., 5n); and - for selecting either one of said antenna devices (5a, 5b,..., 5n) for subsequent reception of signals from said implantable medical device depending on the measured signal quality parameter of said signals received by each of said antenna devices (5a, 5b,..., 5n). - a programmer or monitoring device provided with input and/or output means for transmitting programming instructions to and/or receiving monitoring information from said implantable medical device; - at least two antenna devices (5a, 5b,..., 5n) operatively provided at different locations, wherein - said programmer or monitoring device is connected to said antenna devices (5a, 5b,..., 5n) and is provided for transmitting signals to and receiving signals from said implantable medical device via at least one of said antenna devices (5a, 5b,..., 5n), - each of said antenna devices (5a, 5b,..., 5n) is provided as a physically separated unit wirelessly connected to said programmer or monitoring device, to thereby allow for movements of said programmer or monitoring device relative said antenna devices (5a, 5b,..., 5n), - each of said antenna devices (5a, 5b,..., 5n) comprises at least one conductive radiating antenna element capable of emitting and receiving radio waves of orthogonal polarizations, and - a control unit provided - for measuring a signal quality parameter of signals received from said implantable medical device by each of said antenna devices (5a, 5b,..., 5n); and - for selecting either one of said antenna devices (5a, 5b,..., 5n) for subsequent reception of signals from said implantable medical device depending on the measured signal quality parameter of said signals received by each of said antenna devices (5a, 5b,..., 5n). - for measuring a signal quality parameter of signals received from said implantable medical device by each of said antenna devices (5a, 5b,..., 5n); and - for selecting either one of said antenna devices (5a, 5b,..., 5n) for subsequent reception of signals from said implantable medical device depending on the measured signal quality parameter of said signals received by each of said antenna devices (5a, 5b,..., 5n).