Rich,

The Delta Loop is shorter than a dipole, because a typical installation uses
the tower as a tophat capacitive load for the antenna.  Alpha-Delta makes
commercial models, and from what I've heard, they do quite well and have a
lower takeoff angle than a dipole because of the influence of the tower.

The only reason I don't have one is that I have a guyed tower and there would
be a lot of interaction between the guy wires and the antenna.  I'm not sure
how much it would degrade the performance, but there would be some.

Steve, K8SP