The antenna Mark, 2E0NCG and me used at the 2007 Eagle Radio Group campout was a trap dipole for 17 and 20 metres made from two fibreglass telescopic 5 metre long fishing poles.
The 2 coaxial traps were made from RG-174U coax on a plastic former of a suitable size to fit over the fishing pole, tuned to 18.150MHz using a dip meter.
The elements were made of 6mm copper tape (from eBay, £5 for three rolls) which is self-adhesive and sticks to the poles well.
The centre boom was made from a boom handle, and the centre piece was from an old vacuum cleaner tube.
At the campout we mounted the antenna on a mast about 25ft high, and tested it at 100w, which it accepted without any problems.
Our best DX on the trap dipole was BG7MVZ in China (on 20m SSB), HI3HN in the Dominican Republic (on 17m SSB) and A45WD in Oman (on 17m SSB also).
73 de Paul M0XDX
17m/20m Trap Dipole by Paul M0XDX