Here's my version of the 'ferrite sleeve loop'. I wrote this up in Radio User mag a couple of years ago. There are 39 rods around the hollow centre and about 25 turns tuned with a standard variable cap. It covers 500 KHz to about 2 MHz and works like Billy-O. It's very high Q and can be tricky to get 'on the nose' at the HF end, but it's very effective. There are no active electronics involved, the aerial is completely passive.
The FSL is the invention of the late Graham Maynard, who had a very fertile brain and seemed to ping up ideas on all matters.
His original writings on the FSL can be found here
http://www.zen22142.zen.co.uk/Media/fsi.htm but be prepared to hack your way through lots of tangential meanderings!