Definitely recommend a directional antenna of some kind. Dont get hung up on polarity (Horizontal, Circular) too much. I use a Directive Systems 45 Element Loop Yagi that works nicely. The two best brands if antennas for 23cm base station sat work that are popular today are Directive Systems which makes loop yagis and Wimo which makes 23cm Helix antennas. Both work very well. The most important factor I have found with this band is to keep your horizon as clear as possible. Tree leafs or hills will heavily attenuate your signal on this band more so then 70cm, so elevate your antenna if possible that will help alot. You can get into the bird with as little as 1w if your horizon is completely clear, but if you have big obstructions like massive pine trees like I do, 10w or a bit more may be needed. It's a very fun mode to operate and tinker on.

73 Nick KE8AKW