Patent ID: 8736500

Claim:
An antenna apparatus, comprising: a base; an antenna element having a balanced RF output having a nominal impedance of 300 ohms, and operable to receive RF signals within a first band of frequencies; a mount engaged with said base, and adapted to rotatable support said antenna about an axis of rotation; a balun having a balanced RF input and an unbalanced RF output, and having an impedance ratio of 4:1 therebetween, which provides a nominal impedance transformation from 300 ohms to 75 ohms, said unbalanced output coupled to a circuit having a circuit impedance of 50 ohms; a feed line coupled between said balanced RF output and said balanced RF input, and wherein said feed line comprises two electrical conductors having a predetermined length of 75 millimeters and aligned substantially in parallel, and supportively spaced apart a predetermined distance of 5 millimeters by plural insulators, said feed line further arranged to maintain said predetermined distance between said two electrical conductors as said antenna element rotates with respect to said base, and wherein said predetermined length and said predetermined distance are selected to yield a narrow range of impedances within said first band of frequencies that are substantially centered about said circuit impedance of 50 ohms after being multiplied by said 4:1 impedance ratio, thereby enabling efficient coupling of said RF signals from said balanced RF output having a nominal impedance of 300 ohms to said circuit having a circuit impedance of 50 ohms.