Hi Marcel,

A somewhat unknown antenna, with reasonable gain and easy to
construct is the trihedral reflector antenna (corner radar reflector
as antenna). It uses a monopole as radiatior.

A short acticle (Spanish) with a photo of such an antenna can be found
at: w3.iec.csic.es/ursi/articulos_gandia_2005/articulos/RP1/350.pdf

A long investigation (English) with a high gain trihedral antenna can
be found at: http://yu1aw.ba-karlsruhe.de/shorten3dcra.pdf.

Best Regards,

Wim
PA3DJS
www.tetech.nl