A simple Magloop one of many thousands out there

http://goo.gl/BIQNE a drawing

http://goo.gl/KA5BA a photo

http://goo.gl/Mmh1P a 20M TX @ 5 Watts Spot database from Magloop

As I live in a high density suburb I try to keep a low profile.
I just use coax. inner sliding in one end of a tube as the tuning capacitor, as 5 Watts doesn't generate a high voltage.