Three 490 MHz (Single 8 MHz Channel) 7-El Yagi's in a TRIAD Array was analyzed using 4nec2 after Optimization for Omni-Directional coverage, revealing it is an OMNI-PLUS Antenna (Gain significantly MORE than 0 dBd in ALL Directions), and is Horizontally Polarized, compatible with most Receive TV Antennas.
Min Gain =3.8 dBi, Max Gain =4.3 dBi with SWR between 1.2 and 1.4, which leaves adequate margin for other SWR degradations in a Transmitter Application, such as in the Feedline, Connectors and Proximity to other objects.
Just one 7-El Yagi provides H-POL. Gain = 9.9 dBi, F/R Ratio = 3.4 dB, Beamwidth=44-deg and Characteristic Impedance Zo=200-ohms. So the specific OPTIMIZED Yagi has been specifically crafted to have a specific Beam Pattern...and there is considerable Gain CANCELLATION between the Yagi's in the Array....as well as COHERENT SUMMATION to fill in between each Antenna's 44-deg Beamwidth. So the Yagi's were EXPLICITLY OPTIMIZED for this Application and I wouldn't expect just any off-the-shelf set of Yagis would work anywhere near as well....
