Some time ago I stumbled across the construction plan for a transportable and lightweight quarter-wave vertical telescopic antenna in my local club.
The antenna was designed by draussenfunker.de where you can find the full set of instructions and some image material.
I have also bought a coil as an extension, with which the antenna can also be operated on the 40m band. This is simply screwed directly onto the base of the antenna on the bracket.
