Remember that you want a one to one match between the "feeding" antenna
and the "transmitting" antenna. That will require a splitter combiner
to insure a match.

That splitting/combining device will result in an over 3 db drop in
signal strength. The passive repeater "works" using the gain of the
antennas to overcome the loss between the base stations and the antenna
farm on the hill.

If you must cover two repeaters in different directions to make up for
the "loss" in the splitter you may have to go to a larger number of
elements in the uplink/downlink antennas and or the repeater link
antennas.

The uplink/downlink (to your site) antenna pairs can be either
horizontal or vertical polorization. The repeater link antennas must be
vertical polarization to match the repeater's antenna polarization.

The 20 db loss by using horizontal polarization in the uplink/downlink
pair will reduce the risk of multipath signals at the repeater sites.

The other issue with having two repeater link antennas pointing in two
directions is that you are passively "rebroadcasting" the transmitting
repeater and are distorting (adding to), it's coverage area. You might
want to talk to each of the repeaters owners about that, just to be
safe.

Just some thoughts on this intriguing idea. I have a clear line of
sight to my local repeate and can hit it with my handheld so I have not
implemented this idea myself. The ham that is working on this has
proved it works with tests but wants to upgrade his uplink/downlink
antennas but due to job constraints will be holding off that for a
while. Please let us know how this works for you and I'll post back
after my buddy upgrades his installation.

73

Jim