A jammer transmitter having a comb spectrum generator which includes a pulse generator adapted to produce a pulse train at a frequency corresponding to the channel spacing of signals to be jammed, and a bandpass filter which has a passband including a bandwidth occupied by the signals to be jammed and which is responsive to the pulse train for providing within this bandwidth comb generator output signals at harmonics of the pulse train frequency, a power amplifier operative to amplify the comb g...

1. In a system for jamming wireless communications with the aid of a searching receiver for ascertaining senders which are engaged in the transmission of messages, a powerful jamming transmitter for radiating jamming signals on the waves of ascertained senders, whereby said receiver and transmitter are alternately operative to ascertain transmitting senders and to transmit jamming signals, respectively, which comprises means at the searching receiver for converting received frequency signals int...

1. A method of jamming wireless communications having a frequency falling within a predetermined frequency band, by means of a powerful jamming transmission, comprising the steps of separating out from the predetermined frequency band, by an electrical filtering operation, a suspect transmission signal falling therein, producing an interference signal band having a band width sufficient to include all filtered frequencies, separating out, by an electrical filtering operation, a signal having a f...

1. A repeater comprising an antenna system, a repeater loop consisting solely of broadband elements for coupling the input signal from the input to the output thereof without changing the frequency of the signal at any place in the loop, said elements including at least one broadband translation device, means coupling the input and output of said repeater loop to said antenna system to receive incoming signals and for retransmitting said signals, and means for communicating through said repeater...

A method for reacting to disturbance on an uplink frequency in a mobile communication system which comprises a mobile communication network which includes at least one base station and a mobile services switching center, as well as at least one mobile station which communicates with base station on an uplink, i.e. receive, frequency, and on a downlink, i.e. transmit, frequency of base station. In order to react advantageously to an uplink disturbance, the following procedure will be followed: a ...

A method and device for achieving reliable prevention of cellular telephone calls, within a given area. In the preferred embodiment, the device and method operate to block the control frequencies of the cellular system within a given area. The device broadcasts a blocking signal with a low power output, which interferes with the reception ability and decoding of signals and commands broadcast at the control frequency. Thus, the handshake routine of the telephone/cellular subscriber with the loca...

The object of the call masking system for mobile telephones is to prevent the operation of mobile telephones which are present in a closed environment without interfering with the normal operation of other telephones which are outside the closed environment. To this effect, the system generates interference signals which will prevent the mobile telephones from receiving the signaling channels sent by the base stations (for example, GSM call signaling channel). The system monitors the power with ...

A communications network (10) having a plurality of wireless nodes (12-28) distributed within a region of interest makes routing decisions based on terrain information for the region of interest. A link quality determination unit (54) determines the quality of individual node-to-node links within the network (10), based on the location of the nodes (12-28) and the terrain about the nodes (12-28). A path selection unit 58 then determines an optimal path through the network 10 based on the link qu...

A warning radio receiver is adapted to receive not only a recognition signal for emergency broadcast but also two further recognition signals, namely a warning network transmitter recognition signal and a warning region recognition signal. If, for example, the currently tuned transmitter changes its warning region recognition signal, after the expiration of the timing period of a first timer 16, one or more seeking operations for other transmitters with the predetermined warning region recogniti...

The present invention is related to a cellular phone jammer permitting cellular phones to be used in an emergency, and includes a cellular phone signal-obstructing apparatus and an alarm apparatus. The cellular phone signal-obstructing apparatus further has a cellular phone signal-blocking unit, a power supply unit, and a trigger unit. The cellular phone signal-blocking unit sends out a blocking-signal to disconnect the communication between cellular phones and cellular tower within the effectiv...