Noise reduction device for citizen's band transceivers

Claim 2

A noise reduction device in combination with a transceiver and an antenna therefor, said transceiver having a transmission mode and a reception mode and including a lead conductor and a shield conductor, said antenna including an antenna cable having a lead and shield thereof normally connected to said transceiver lead conductor and shield conductor respectively, said noise reduction device comprising: (a) a solid state means having a first, a second, and a third terminal, each terminal including a lead connected thereto, said first and second terminals normally having a high impedance therebetween and having a low impedance therebetween in response to a suitable bias signal applied to said third terminal; (b) said solid state means being interposed between said transceiver and said antenna for reducing the signal strength to said transceiver during the reception mode by means of said normal high impedance between said first and second terminals, said first terminal being connected to said antenna cable lead and said second terminal being connected to said transceiver lead conductor, and said antenna cable shield being connected to said transceiver shield conductor; and (c) a bias antenna connected to said third terminal and operative upon reception of radio frequency energy emitted by said transceiver during said transmission mode to apply said energy as a suitable bias signal to said third terminal thereby effecting said low impedance between said first and second terminals.

Claim 3

A noise reduction device as set forth in claim 1 wherein: (a) said solid state means is a transistor having an emitter, a collector, and a base; and (b) said first terminal is connected to the emitter of said transistor, said second terminal is connected to the collector of said transistor, and said third terminal is connected to the base of said transistor.

Claim 4

A noise reduction device as set forth in claim 1 wherein said bias antenna is said third terminal lead cut to a selected length.

Claim 5

A noise reduction device as set forth in claim 1 including a switch connected between said first and second terminals and selectively closable to bypass said solid state means.

Claim 6

A noise reduction device as set forth in claim 4 wherein said transceiver includes an antenna receptacle, including a lead conductor and a shield terminal connected to said transceiver shield conductor, and wherein said antenna cable terminates in an antenna cable plug having a lead portion and a shield portion connected respectively to said antenna cable lead and shield, said antenna cable plug being normally receivable in said transceiver antenna receptacle, said device including: (a) a device receptacle having a lead portion connected to said solid state means first terminal and a shield portion, said antenna cable plug being received in said device receptacle; (b) a device cable having a lead and a shield, said device cable lead being connected to said solid state means second terminal, said device cable shield being connected to said device receptacle shield portion; and (c) said device cable terminating in a device cable plug having a lead portion and a shield portion connected respectively to said device cable lead and shield, said device cable plug being received in said transceiver antenna receptacle.

Claim 7

A noise reduction device as set forth in claim 5 including a housing enclosing said solid state means, mounting said switch and said device receptacle, and having said device cable extending therefrom.

Claim 8

A noise reduction device adapted for operable connection with a transceiver and an antenna therefor, and wherein said transceiver has a transmission mode and a reception mode and includes a lead conductor and a shield conductor, and wherein said antenna includes an antenna cable having a lead and a shield thereof normally for connection to said transceiver lead conductor and shield conductor respectively, said noise reduction device comprising: (a) a housing; (b) a transistor mounted in said housing, said transistor including an emitter, a collector, and a base and respective leads thereof, said emitter and collector normally having a substantially high impedance therebetween and having a low impedance therebetween in response to the application of a suitable bias signal to said base, said normal high impedance being adapted for reducing signal strength to said transceiver during the reception mode thereof; (c) emitter connector means mounted on said housing, connected to said emitter, and adapted for connection of said emitter to said antenna cable lead; (d) collector connector means supported by said housing, connected to said collector, and adapted for connection of said collector to said transceiver lead conductor; (e) shield connector means in association with said emitter connector means and said collector connector means for connection of said antenna cable shield to said transceiver shield conductor; and (f) a bias antenna connected to said transistor base and operative upon reception of radio frequency energy emitted by said transceiver during the transmission mode thereof to apply said energy as a suitable bias signal to said base thereby effecting said low impedance between said emitter and said collector.

Claim 9

A noise reduction device adapted for operable connection with a transceiver and an antenna therefor, and wherein said transceiver has a transmission mode and a reception mode and includes a lead conductor and a shield conductor, and wherein said antenna includes an antenna cable having a lead and a shield thereof normally for connection to said transceiver lead conductor and shield conductor respectively, said noise reduction device comprising: (a) a housing; (b) a transistor mounted in said housing, said transistor including an emitter, a collector, and a base and respective leads thereof, said emitter and collector normally having a substantially high impedance therebetween and having a low impedance therebetween in response to the application of a suitable bias signal to said base, said normal high impedance being adapted for reducing signal strength to said transceiver during the reception mode thereof; (c) emitter connector means mounted on said housing, connected to said emitter, and adapted for connection of said emitter to said antenna cable lead; (d) collector connector means supported by said housing, connected to said collector, and adapted for connection of said collector to said transceiver lead conductor; (e) shield connector means in association with said emitter connector means and said collector connector means for connection of said antenna cable shield to said transceiver shield conductor; and (f) a bias antenna connected to said transistor base and operative upon reception of radio frequency energy emitted by said transceiver during the transmission mode thereof to apply said energy as a suitable bias signal to said base thereby effecting said low impedance between said emitter and said collector.

Claim 10

A noise reduction device as set forth in claim 7 wherein said transceiver includes an antenna receptacle having a lead terminal and a shield terminal connected respectively to said transceiver lead and shield conductors and wherein said antenna cable terminates in an antenna cable plug having a lead portion and a shield portion connected respectively to said antenna cable lead and shield, said antenna cable plug being normally receivable in said transceiver antenna receptacle, said noise reduction device including: (a) a device receptacle mounted on said housing and having a lead portion and a shield portion, said lead portion being connected to said emitter and comprising said emitter connector means, said device receptacle being adapted for removable reception of said antenna cable plug; (b) a device cable extending from said housing and having a lead and a shield, said device cable lead being connected to said collector, said device cable shield and said device receptacle shield portion being interconnected and comprising said shield connector means; and (c) said device cable terminating in a device cable plug having a lead portion and a shield portion connected respectively to said device cable lead and shield, said device cable plug lead and said device cable lead comprising said collector connector means, said device cable plug being adapted for removable insertion into said transceiver antenna receptacle.