VEHICLE-MOUNTED ANTENNA AND COUPLING CIRCUIT THEREFOR

• US 3,725,942 A
• Filed: 04/22/1965
• Issued: 04/03/1973
• Est. Priority Date: 04/22/1965
• Status: Expired due to Term

• Current Assignee: Milosh L. Ukmar
• Original Assignee: Milosh L. Ukmar
• Inventors: Ukmar, Milosh L.
• Primary Examiner(s): Saalbach, Herman Karl
• Assistant Examiner(s): Nussbaum, Marvin
• Application Number:
  US04/450,027
• Time in Patent Office: 2,903 Days
• Field of Search: 343/715,858,866,741,852,749,750 325/21,25,172-180
• US Class Current: 343/715
• CPC Class Codes: H01Q 1/3275 mounted on a horizontal surface of the vehicle, e.g. on roof, hood, trunk
• CPC Class Codes: H01Q 5/50 Feeding or matching arrangements for broad-band or multi-band operation
• CPC Class Codes: H01Q 9/145 by varying the electrical length
• CPC Class Codes: H01Q 9/30 with feed to end of elongated active element, e.g. unipole H01Q9/44 takes precedence

Abstract

Vehicle-mounted antenna system having a novel coupling circuit connected between the end of an antenna lead-in cable away from the latter'"'"''"'"'s connection to a conventional standard broadcast antenna and a standard broadcast (A.M.) radio receiver and citizens band communications equipment. This coupling circuit: 1. PASSES STANDARD BROADCAST SIGNALS TO THE STANDARD BROADCAST RECEIVER AND BLOCKS INCOMING CITIZENS BAND SIGNALS FROM THIS RECEIVER; 2. PASSES CITIZENS BAND SIGNALS AND BLOCKS STANDARD BROADCAST SIGNALS BETWEEN THE ANTENNA AND THE CITIZENS BAND COMMUNICATIONS EQUIPMENT; 3. INCREASES THE EFFECTIVE ELECTRICAL LENGTH OF THE ANTENNA FOR EFFICIENT TRANSMISSION AND RECEPTION OF CITIZENS BAND SIGNALS; AND 4. IMPEDANCE MATCHES THE ANTENNA LEAD-IN CABLE TO THE CITIZENS BAND COMMUNICATIONS EQUIPMENT.

Claims

1. A coupling circuit for connecting citizens band communications equipment to a vehicle-mounted antenna having a length substantially less than 1/4 wavelength for citizens band signals and provided with an antenna lead-in cable, said coupling circuit comprising filter circuit means for connection between said communications equipment and said cable and effective to reject incoming standard broadcast signals, said filter circuit means having sufficient inductive reactance to increase substantially the effective electrical length of the antenna for efficient transmission or reception of citizens band signals.

2. A coupling circuit according to claim 1, wherein said filter circuit means comprises first condenser means and a first coil connected in series with each other.

3. A coupling circuit for connecting citizens band communications equipment to a vehicle-mounted antenna having a length substantially less than one-quarter wavelength for citizens band signals and provided with an antenna lead-in cable having an impedance substantially greater than that of said communications equipment, said coupling circuit comprising filter circuit means for connection at one end to the antenna lead-in cable and effective to reject incoming standard broadcast signals and to pass signals in the citizens band, said filter circuit means having sufficient inductive reactance therein to increase substantially the effective electrical length of the antenna for efficient transmission or reception of signals in the citizens band, and impedance matching means including a step-up transformer connected to the opposite end of said filter circuit means for matching the impedance of said communications equipment to that of the antenna lead-in cable.

4. A coupling circuit for connecting citizens band communications equipment to a vehicle-mounted antenna having a length substantially less than one-quarter wavelength for citizens band signals and provided with an antenna lead-in cable having an impedance substantially greater than that of said communications equipment, said coupling circuit comprising filter circuit means for connection at one end thereof to the antenna lead-in cable away from the antenna and operative to reject standard broadcast signals and to pass citizens band signals, said filter circuit means having sufficient inductive reactance to increase substantially the effective electrical length of the antenna for efficient transmission or reception of signals in the citizens band, impedance matching means connected at one end thereof to the oppositE end of said filter circuit means and including a step-up transformer to match the impedance of said communications equipment to that of the antenna lead-in cable, and a blocking condenser connected to the opposite end of said impedance matching means.

5. A coupling circuit for connecting citizens band communications equipment to a vehicle-mounted antenna having a length substantially less than one-quarter wavelength for citizens band signals and provided with an antenna lead-in cable having an impedance substantially greater than that of said communications equipment, said coupling circuit comprising:

a series L-C circuit for connection at one end thereof to the antenna lead-in cable remote from the antenna, said series L-C circuit having series-connected first condenser means and a first coil, said first coil having an inductive reactance sufficient to increase substantially the effective electrical length of the antenna for efficient transmission or reception of signals in the citizens band, said series L-C circuit constituting a rejection filter for rejecting incoming standard broadcast radio signals and for passing citizens band signals; and

a parallel L-C circuit connected to the opposite end of said series L-C circuit and comprising parallel-connected second condenser means and a second coil, said second coil having one terminal thereon grounded and another terminal thereon connected to said series L-C circuit and a tap intermediate said terminals for connection to said communications equipment, said second coil providing a step-up transformer for matching the impedance of the communications equipment to that of the antenna lead-in cable.

6. A coupling circuit for connecting both a standard broadcast radio receiver and citizens band communications equipment to the lead-in cable of a vehicle-mounted antenna having a length substantially less than 1/4 wavelength for citizens band signals, said coupling circuit comprising first filter circuit means for connection between the antenna lead-in cable and the citizens band communications equipment and effective to reject incoming standard broadcast radio signals and to pass signals in the citizens band, said first filter circuit means having sufficient inductive reactance to increase substantially the effective electrical length of the antenna for efficient transmission or reception of citizens band signals, and second filter means for connection between the antenna lead-in cable and the standard broadcast radio receiver and effective to reject citizens band signals and to pass standard broadcast radio signals, said first and second filter means being in parallel to each other for connection to said antenna lead-in cable, whereby, upon connection of a citizen band set (receiver, transmitter, or transceiver) and a standard broadcast set to said first and second filter means, respectively, each set will be operational.

7. A coupling circuit for connecting both a standard broadcast radio receiver and citizens band communications equipment to a vehicle-mounted antenna having a length substantially less than 1/4 wavelength for citizens band signals and having a lead-in cable with an impedance substantially greater than that of said communications equipment, said coupling circuit comprising first filter circuit means for connection at one end to the antenna lead-in cable and effective to reject incoming standard broadcast radio signals and to pass signals in the citizens band, said first filter circuit means having sufficient inductive reactance to increase substantially the effective electrical length of the antenna for efficient transmission or reception of citizens band signals, impedance matching means connected to the opposite end of said first filter circuit means and operative to match the impedance of said communications equipment to that of the antenna lead-in cable, and second filter means for connection between the antenna lead-in cable and the standard broadcast radio receiver and effectIve to reject citizens band signals and to pass standard broadcast radio signals, said first and second filter means being in parallel to each other for connection to said antenna lead-in cable, whereby, upon connection of a citizen band set (receiver, transmitter, or transceiver) and a standard broadcast set to said first and second filter means, respectively, each set will be operational.

8. A coupling circuit for connecting both a standard broadcast radio receiver and citizens band communications equipment to a vehicle-mounted antenna having a length substantially less than one-quarter wavelength for citizens band signals and provided with a lead-in cable having an impedance substantially greater than that of said equipment, said coupling circuit comprising first filter circuit means for connection at one end to the antenna lead-in cable away from the antenna and effective to reject incoming standard broadcast radio signals and to pass signals in the citizens band, said first filter circuit means having sufficient inductive reactance to increase substantially the effective electrical length of the antenna for efficient transmission or reception of citizens band signals, impedance matching means including a step-up transformer connected to the opposite end of said first filter circuit means and operative to match the impedance of said citizens band communications equipment to that of the antenna lead-in cable, and second filter means for connection between the antenna lead-in cable and the standard broadcast radio receiver and effective to reject citizens band signals and to pass standard broadcast radio signals, said first and second filter means being in parallel to each other for connection to said antenna lead-in cable, whereby, upon connection of a citizen band set (receiver, transmitter, or transceiver) and a standard broadcast set to said first and second filter means, respectively, each set will be operational.

9. A coupling circuit for connecting both a standard broadcast radio receiver and citizens band communications equipment to a vehicle-mounted antenna having a length substantially less than 1/4 wavelength for citizens band signals and provided with a lead-in cable having an impedance substantially greater than that of said communications equipment, said coupling circuit comprising:

a series L-C circuit for connection at one end thereof to the antenna lead-in cable remote from the antenna, said series L-C circuit having series-connected first condenser means and a first coil, said first coil having an inductive reactance sufficient to increase substantially the effective electrical length of the antenna for efficient transmission or reception of signals in the citizens band, said series L-C circuit constituting a rejection filter for rejecting incoming standard broadcast radio signals and for passing citizens band signals;

a parallel L-C circuit connected at one end thereof to the opposite end of said series L-C circuit and comprising parallel connected second condenser means and a second coil, said second coil having one terminal thereon grounded and, another terminal thereon connected to said series L-C circuit and a tap intermediate said terminals for connection to the citizens band communications equipment, said second coil providing a step-up transformer for matching the impedance of said communications equipment to that of the antenna lead-in cable;

a blocking condenser connected to said intermediate tap and adapted to be connected to said communications equipment; and

a choke coil for connection between the antenna lead-in cable and the standard broadcast radio receiver and effective to reject citizens band signals and to pass standard broadcast radio signals.

10. An antenna system comprising a vehicle-mounted antenna having a length substantially less than 1/4 wavelength for citizens band signals, an antenna lead-in cable connected to said antenna, and a coupling circuit comprising filter circuit means For connection to said cable away from the antenna and effective to reject incoming standard broadcast signals and to pass citizens band signals, said filter circuit means having sufficient inductive reactance to increase substantially the effective electrical length of the antenna for efficient transmission or reception of citizens band signals.

11. An antenna system for citizens band communications equipment comprising a vehicle-mounted antenna having a length substantially less than 1/4 wavelength for citizens band signals, an antenna lead-in cable having an impedance substantially different from that of said communications equipment, and a coupling circuit comprising filter circuit means connected at one end to the antenna lead-in cable remote from the antenna and effective to reject incoming standard broadcast radio signals and to pass citizens band signals, said filter circuit means having sufficient inductive reactance to increase substantially the effective electrical length of the antenna for efficient transmission or reception of signals in the citizens band, and impedance matching means connected to the opposite end of said filter circuit means to match the impedance of said communications equipment to that of the antenna lead-in cable.

12. An antenna system for both a standard broadcast radio receiver and citizens band communications equipment comprising a vehicle-mounted antenna having a length substantially less than 1/4 wavelength for citizens band signals, an antenna lead-in cable connected to the antenna, and a coupling circuit comprising first filter circuit means connected to the antenna lead-in cable away from the antenna and effective to reject incoming standard broadcast radio signals and to pass signals in the citizens band, said first filter circuit means having sufficient inductive reactance to increase substantially the effective electrical length of the antenna for efficient transmission or reception of citizens band signals, and second filter means connected to the antenna lead-in cable away from the antenna and effective to reject citizens band signals and to pass standard broadcast radio signals.

13. An antenna system for both a standard broadcast radio receiver and citizens band communications equipment comprising a vehicle-mounted antenna having a length substantially less than 1/4 wavelength for citizens band signals, an antenna lead-in cable connected to said antenna and having an impedance substantially greater than that of said communications equipment, and a coupling circuit comprising first filter circuit means connected at one end to the antenna lead-in cable remote from the antenna and effective to reject incoming standard broadcast radio signals and to pass signals in the citizens band, said first filter circuit means having sufficient inductive reactance to increase substantially the effective electrical length of the antenna for efficient transmission or reception of citizens band signals, impedance matching means connected to the opposite end of said first filter circuit means to match the impedance of said communications equipment to that of the antenna lead-in cable, and second filter means connected to the antenna lead-in cable remote from the antenna and effective to reject citizens band signals and to pass standard broadcast radio signals.

14. In combination on a vehicle, a standard broadcast radio receiver;

citizens band communications equipment;

a vehicle-mounted antenna having a length substantially less than 1/4 wavelength for citizens band signals;

an antenna lead-in cable connected to the antenna and having an impedance substantially greater than that of said communications equipment;

first filter circuit means connected at one end to the antenna lead-in cable remote from the antenna and effective to reject incoming standard broadcast radio signals and to pass signals in the citizens band, said first filter circuit means having sufficient inductive reactance to increasE substantially the effective electrical length of the antenna for efficient transmission or reception of citizens band signals;

impedance matching means connected between the opposite end of said first filter circuit means and said communications equipment to match the latter'"'"''"'"'s impedance to that of the antenna lead-in cable; and

second filter means connected between the antenna lead-in cable and said standard broadcast receiver and effective to reject citizens band signals and to pass standard broadcast radio signals.

15. In combination on a vehicle, a standard broadcast radio receiver;

citizens band communications equipment;

a vehicle-mounted antenna having a length substantially less than 1/4 wavelength for citizens band signals;

an antenna lead-in cable connected to the antenna and having an impedance substantially greater than that of said communications equipment;

a series L-C circuit connected at one end thereof to the antenna lead-in cable remote from the antenna, said series L-C circuit having series-connected first condenser means and a first coil, said first coil having an inductive reactance sufficient to increase substantially the effective electrical length of the antenna for efficient transmission or reception of signals in the citizens band, said series L-C circuit constituting a rejection filter for rejecting incoming standard broadcast radio signals and for passing citizens band signals;

a parallel L-C circuit connected at one end thereof to the opposite end of said series L-C circuit and comprising parallel connected second condenser means and a second coil, said second coil having one terminal thereon grounded and another terminal thereon connected to said series L-C circuit and a tap intermediate said terminals for connection to the citizens band communications equipment, said second coil providing a step-up transformer for matching the impedance of said communications equipment to that of the antenna lead-in cable;

a blocking condenser connected between said intermediate tap and said communications equipment; and

a choke coil connected between the antenna lead-in cable and the standard broadcast radio receiver and effective to reject citizens band signals and to pass standard broadcast radio signals.