Patent ID: 7113752

Claim:
A method for securing operation of a receiver in a radio apparatus, in which a transmitter operates in a certain transmit band and the receiver operates in a certain receive band, and which radio apparatus has a transmitting antenna and a receiving antenna separate from one another, a first transmitting filter and receiving filter, the radio apparatus further comprising at least a second transmitting filter a stop-band attenuation of which in the receive band is substantially greater than the stop-band attenuation of the first transmitting filter in the receive band, the method comprising steps; strength of a field reflected from the transmitting antenna is repeatedly measured, a relative strength of the reflected field is compared to a certain threshold value, the second transmitting filter is selected to be operating transmitting filter if said relative strength exceeds the threshold value, and the first transmitting filter is selected to be operating transmitting filter if said relative strength is below the threshold value.