The classic dipole.  It can be installed as a flat top with gain broadside to the elements
or as an inverted V with an omni-directional pattern.  In limited space installations, it
can be bent and zig-zaged as required to fit into available space.   A high quality
antenna tuner such as an LDG will allow this antenna to work 20-10 meters

This 20M dipole antenna is 33ft long and made with FLEX-WEAVE antenna wire and 1:1 balun.