a relatively simple antenna that is designed to amplify signals from 3 to 3000 MegaHertz.
http://www.uoguelph.ca/~antoon/circ/activant2.html
A one metre whip will develop a fair signal voltage on HF, but there is next to no current. By amplifying the signal at source you will get a much better antenna.
http://www.hard-core-dx.com/nordicdx/antenna/special/swactive.html
On the shortwave band this active antenna is comparable to a 20 to 30 foot wire antenna.
http://www.uoguelph.ca/~antoon/circ/activant.html
With only a small handfull of parts you can built this trusty FM Amplifier.
http://www.uoguelph.ca/~antoon/circ/activefm.html
can be used for AM, FM, and shortwave.
http://www.hard-core-dx.com/nordicdx/antenna/hidden/active2.html
This active antenna is good down to at least 10 KHz and is a few dB down at 200 KHz. You may like to experiment with the filtering to see if Long wave and Medium wave may be covered.
http://www.hard-core-dx.com/nordicdx/antenna/special/vlfactive.html
There have been various comments here regarding the effectiveness (or otherwise) of active antennas.
http://www.hard-core-dx.com/nordicdx/antenna/hidden/active1.html