I have used some long Yagi antennas for ham radio applications (VHF, UHF & L-band).
They are fine for long distance work. Even for tracking satellites, with the right rotors.
The beam width is so narrow, I would not think of using one for ADS-B . Since it would be very hard
to hear planes that were 20 to 200nm behind or off to the side of the beam pattern.
However, if you were living very far away from the
nearest air port(200-300 nm) and never had planes flying around your local area,
it might be a good antenna to point at the airport area.
The antenna that's getting good reviews, is the DPD..
http://forum.planefinder.net/threads/dpd-ads-b-vertical-outdoor-base-antenna.111/
It's pattern looks more like this.. omni-directional
