The Norcal Doublet Antenna: http://www.norcalqrp.org/norcaldoublet.htm
The Norcal Doublet is a simple antenna that is 44 feet (13.4 metres) long, 22 feet (6.7 metres) per side. The Norcal pages report "...that the antenna would have basically the same radiation patterns on all bands from 40 - 10 meters. This would be very handy to have for field operation..... You will need the following materials: 50 feet of 4 core stranded computer cable; 1 #0 Fishing Swivel; 1 Cable tie; 2 pieces of fishing cord."
The antenna can be hung from trees or cheap telescopic 'roach' / Sota poles. Doubling the size would allow operation on 80 metres and even 160 metres by shorting the twin feed together at the transmitter end and feeding it against a good earth as a 'Marconi' type antenna.