For a while, we have been big fans of the RF Elements horn antenna. On our tower, we have replaced all the sectors with horns.  However, on many of our mini-pop locations, we were using smaller omni antennas. This allowed us to only have to install one radio and keep the package fairly small.  

On one of our mini-pops, we were having some interference issues as well as a couple subscribers that were shooting through a tree and performance was taking a hit.

There is the original install.  Below is a section of the radio performance page to show you what that AP looked like from a signal perspective (you'll need to reference via IP address for comparison):

Couple of those subscribers were not doing so well and we were seeing a fair amount of interference issues (despite frequency selected) on the north side of town (to the right on the photo). In fact, some subscribers would not even associate with this antenna but others nearby would.

So, we decided to give the horns a try here.  We pulled down the omni and put up a 60 degree horn facing north and a 70 degree horn facing more south / west.  Most of the subscribers are to the north. That AP kept the same frequency and power settings - just a new antenna.  The 70 degree horn is on an adjacent frequency now (GPS syncronized).

Here is what the radio performance looks like for the two radios. The radio with more subscribers is the north radio on the same channel and power as the omni was.

Immediate improvement in signal, SNR and speeds to the subscribers.  A couple subscribers that were no longer able to hit their speed package (with a TCP test) are now able to do so - just with a simple antenna replacement from omni to horn.

While omni's have a place (sometimes), we are getting away from them whenever possible and sticking with an antenna design that keeps working for us no matter where we install it.