Abstract: A method and device for monitoring a mobile telephone repeater are disclosed. The repeater is of the kind comprising an uplink (100) and a downlink (200) between two antennas (1, 2), wherein the repeater receives, amplifies and retransmits signals between a base station and a mobile telephone. A stability test is performed automatically, whereby a possible continuous and strong signal, being caused either by an instability involving a positive feedback between the two antennas or by a disturbing signal, is detected, whereupon the amplifying gain is adjusted in response to the result of the stability test. The test criterion includes the step of checking whether the level of the input signal in the respective amplifier chain exceeds a threshold value during at least a major portion of a measuring period.

Abstract: An improved repeater for receiving and re-transmitting radio signals for a cell in a cellular telecommunication system. The repeater raises the levels and is capable of converting the frequencies of the radio signals used in the telecommunication system. Due to the power amplifiers being provided between the channel selecting means and combiner, the power amplifier needs only to amplify one frequency band. In this way the repeater gets a simpler design, demands less maintenance, and gets a higher degree of efficiency in combination of high power capacity and generation of low levels only of intermodulation products.