Given: XYZ Company is constructing a building-to-building ERP-OFDM bridge link using patch antennas. The buildings are 4 blocks apart in the middle of
a large city. XYZ Company is using the rooftop of each building for antenna placement. There are several buildings closely spaced between the two locations, but there is a narrow visual line-of-sight. The link does not work as XYZ Company had
hoped.
What would you do to rectify this problem at the lowest possible cost?

A.
Change the antennas to high gain parabolic dish or grid antennas with a narrowbeamwidth.
This will
sufficiently shrink the Fresnel Zone to an area where other buildings are not impeding.

B.
Decrease the output power to the minimum allowed by the link budget calculation. This will minimize the size of the Fresnel Zone and increase the quality of the wireless link.

C.
Use a vertically-polarized antenna on one building and a horizontally-polarized antenna on the other to decrease the size of the Fresnel Zone. Cross-polarization will shrink the Fresnel Zone size while allowing the output power to remain the same.

D.
On top of each building, place a mast or tower that is tall enough to completely clear the Fresnel Zone of obstructions between the two antennas.