Sean Gilbert, G4UCJ, has improved his most famous Hula Hoop Loop antenna.
There are several modifications, more detailed explanations, and several new photos of how to construct this amazing DX loop.
Where the loop really scores is in the MW band, where it works best and signals that are S9 on the loop quite often are inaudible on my other antennas.
But not only that.
As an aside, the loop also work as an impressive active antenna for the shortwave bands!
The only disadvantage about using the loop as an active antenna on the HF bands is that it does tend to pick up a fair amount of electrical noise, and, of course, above 2MHz, the directional properties pretty much disappear.
That said, if you have antenna restrictions then this could be a way to hear some interesting stations without upsetting anyone.
See full info at http://www.hard-core-dx.com/nordicdx/antenna/loop/hulaloop.html