Hy, Bratters, looks interesting but the word Directional would tend to put me off as you are trying to receive a moving object unless of course you intend to try & increase your receive from a specific direction, Is it possible that it can be used in conjunction with an existing antenna, I would not think it was possible on the other hand I could be wrong. Lets see what the more technical guys on the forum have to say.
Cheers de Peter 2W1 FJZ.