While looking for a does it all antennae for my Kenwood R5000 receiver
(with the 108-174 MHz option) I came across this website:

http://www.g8jnj.net/activeantennas.htm

The Clifton Labs Active monopole is of particular interest to me as he
says "This circuit seems to work very well, and has an extremely flat
frequency response from about 10KHz upto 180MHz." That would cover the
whole range of my receiver.

Anyone have any experience of this, or any other active antennae? I'd
rather build one than buy one, anyone got any designs they can recommend?

Thx.