Abstract: Systems and methods are provided for operating an existing antenna at a second, higher frequency. To this end, an antenna system includes an antenna feed and a first antenna assembly electrically connected to the antenna feed at a first end. The first antenna assembly has a first electrical length for a first frequency band and includes a substantially linear segment. A second antenna element is connected to the first antenna assembly and extends away from the first end of the first antenna assembly in a direction substantially parallel to the substantially linear segment. The second antenna element has an electrical length of one-quarter of a wavelength associated with a second frequency.

Abstract: Systems and methods are provided for operating an existing antenna at a second, higher frequency. To this end, an antenna system includes an antenna feed and a first antenna assembly electrically connected to the antenna feed at a first end. The first antenna assembly has a first electrical length for a first frequency band and includes a substantially linear segment. A second antenna element is connected to the first antenna assembly and extends away from the first end of the first antenna assembly in a direction substantially parallel to the substantially linear segment. The second antenna element has an electrical length of one-quarter of a wavelength associated with a second frequency.

Abstract: A broad-band impedance-matching device for an RF vacuum tube power amplifier incorporates a circuit having multiple inductors and capacitors interconnected in an impedance-matching circuit, said circuit having a low impedance input and high impedance output and made up of a plurality of series connected inductors and capacitors. Impedance transformation is performed in a number of small steps, which enables the use of a much lower cue than would be necessary if the impedance transformation were done in a single step. The arrangement produces an impedance transformation which holds over a relatively broad band width, making in unnecessary for any fine tuning of the network.

Abstract: A stereo FM pilot signal generator which includes an automatic phase correction loop so as to automatically synchronize the phase between the pilot signal and the stereo switching signal. A parallel clocked divider/decoder is included for generating a 38 kHz square wave, to be used in a stereo switching modulator, and a 19 kHz square wave so that the two square wave signals are substantially in phase synchronism with one another. The 19 kHz square wave is directed through a controllable phase adjuster and then through a filter which serves to remove higher harmonics therefrom so that only the fundamental, 19 kHz sine wave signal remains. The phase of the 19 kHz square wave signal is compared with the phase of the 19 kHz sine wave signal by a phase comparator which provides a control signal to the phase adjuster, and which adjusts this control signal until the 19 kHz sine wave is substantially in phase synchronism with the 19 kHz square wave.

Abstract: A switchable gain amplifier for use in an FM broadcasting system wherein the gain of a modulating signal is automatically switched to a selected level in accordance with the use or non-use of plural input channels.