Look at the "Portable Dipole" article in the "Articles" section of my website at www.ad5x.com
. It is simple to build, cheap, light, and covers 40-10 meters. It is a 20-meter dipole that uses switches to disconnect sections of the antenna for 20-10 meters, and loading coils clipped across the 10-meter switch for 40- and 30-meters. Works great!
Phil - AD5X