I thought about using one of these for DTV reception. I am curious about
the feed point impedance. The antenna (see it at radioshack.com) looks like
a corner reflector of sorts. But, it has an extended boom ahead of the feed
point dipole with yagi like elements (cut much shorter than the dipole).
The feed point is an approx. 1/2 wave split dipole, insulated and center
fed.
The feed point 1/2 wave dipole (center fed) would have a 75 ohm impedance
free space. Corner reflector design data shows an approx. 70 ohm impedance
for a similar configuration, but without the extended boom ahead of the feed
dipole.
The RadioShack accompaning literature implies a 200-300 ohm feed point
impedance, ie. it states that a 300 / 75 ohm balun and RG-6 feed line should
be attached. Has anyone measured, or modeled the feed point impedance of
this antenna or have an explanation of how they arrive at 200-300 ohms?
N4AOX