Abstract: An optimized coaxial transmission line having joined segments of coaxial transmission lines is provided. First insulating supports positioned at flange joints within the joined segments are provided. Second insulating supports are positioned a distance x, where x = 1 4 ? ? + n · 1 2 ? ? , from the first insulating supports to cancel reflections created by the insulating supports. Preferably, x=¼?, and the second insulating supports are positioned for one quarter of a wavelength at either FM frequencies, VHF frequencies, UHF frequencies, or IBOC frequencies. A method for optimizing a transmission line by frequency is also provided. First, segments of coaxial transmission lines are joined together, each segment having a first insulating support positioned at a flange joints within the joined segment.

Abstract: An optimized coaxial transmission line having joined segments of coaxial transmission lines is provided. First insulating supports positioned at flange joints within the joined segments are provided. Second insulating supports are positioned a distance x, where x = 1 4 ? ? + n · 1 2 ? ? , from the first insulating supports to cancel reflections created by the insulating supports. Preferably, x=¼?, and the second insulating supports are positioned for one quarter of a wavelength at either FM frequencies, VHF frequencies, UHF frequencies, or IBOC frequencies. A method for optimizing a transmission line by frequency is also provided. First, segments of coaxial transmission lines are joined together, each segment having a first insulating support positioned at a flange joints within the joined segment.

Abstract: A ganged circulator device for isolating a transmitter and increasing the power level, isolation performance, and input VSWR performance of an IBOC combiner module is provided. The ganged circulator device includes an input power divider, a ganged circulator module, and an output power combiner. The input power divider includes a first input port, a second input port, and a plurality of output ports. The ganged circulator module includes a plurality of circulators and a plurality of load resistors. The module also includes input ports corresponding to and electrically connected to the plurality of output ports on the input power divider. The output power combiner includes a first output port, a second output port, and plurality of input ports corresponding to and electrically connected to a plurality of output ports of the ganged circulator module.

Abstract: A phase shift is defined as a point in frequency at which the phase is changed from 0 degrees to 180 degrees. A device is provided for combining analog and digital in-band-on-channel (IBOC) signals to feed a common antenna utilizing phase shifting allpass filter modules to provide a 180 degree phase shift to specific IBOC channels within a constant impedance dual-hybrid circuit. The IBOC Allpass combiner includes one input 90 degree 3 dB quadrature hybrid coupler, one output 90 degree 3 dB quadrature hybrid coupler, a load resistor, and two phase shifting allpass filter modules. Each phase shifting allpass filter module is comprised of a two coaxial cavity resonators coupled to a 90 degree 3 dB quadrature hybrid coupler. Components and modules are coupled using mating transmission lines. The four coaxial cavity resonators are used as devices to produce two distinct phase shifts at isolated upper and lower IBOC side band frequencies.

Abstract: A phase shift is defined as a point in frequency at which the phase is changed from 0 degrees to 180 degrees. A device is provided for combining analog and digital in-band-on-channel (IBOC) signals to feed a common antenna utilizing phase shifting allpass filter modules to provide a 180 degree phase shift to specific IBOC channels within a constant impedance dual-hybrid circuit. The IBOC Allpass combiner includes one input 90 degree 3 dB quadrature hybrid coupler, one output 90 degree 3 dB quadrature hybrid coupler, a load resistor, and two phase shifting allpass filter modules. Each phase shifting allpass filter module is comprised of a two coaxial cavity resonators coupled to a 90 degree 3 dB quadrature hybrid coupler. Components and modules are coupled using mating transmission lines. The four coaxial cavity resonators are used as devices to produce two distinct phase shifts at isolated upper and lower IBOC side band frequencies.

Abstract: A ganged circulator device for isolating a transmitter and increasing the power level, isolation performance, and input VSWR performance of an IBOC combiner module is provided. The ganged circulator device includes an input power divider, a ganged circulator module, and an output power combiner. The input power divider includes a first input port, a second input port, and a plurality of output ports. The ganged circulator module includes a plurality of circulators and a plurality of load resistors. The module also includes input ports corresponding to and electrically connected to the plurality of output ports on the input power divider. The output power combiner includes a first output port, a second output port, and plurality of input ports corresponding to and electrically connected to a plurality of output ports of the ganged circulator module.