The reflected W beam
The first time that this kind of antenna has been announced was in the 80's in Great Britain where HAM's described this design as a result of changing the reflected M or X-beam.
Starting from a 2 element yagi going to a Moxon beam and from there to the reflected M beam we finally came to this design which is mechanically a bit more difficult than the reflected M but gives better wind load conditions and again a smaller tuning radius for the same band.
Since the beginning of the 90's Traffie Technology in the USA is building/selling different monoband and multiband versions.
I was always looking for a solution for my DXpeditions and finally came to the this kind of antenna about 1999. Meanwhile I have calculated and built a high number of different band designs and published the (IMHO) most interesting. Especially the 5 band version going from 20-10m has been build many dozen times in more than 20 countries worldwide. The latest versions were multiband designs starting from 40m.
We don't need big tower installations or the strongest rotor. And often your neighbour will not recognize this as an antenna...
The reflected W beam is a 2 element antenna (reflector & radiator) with folded elements. The elements have full size (not shorted) for the band but are folded in the shape of 2 W's seeing each other. In this construction the elements are very close together at the ends and in the middle. So the coupling of the elements is in the magnetic field component instead in the electrical like for a yagi. This makes this antenna very quiet. It sounds on the receiver more like a closed loop as like a yagi design.
Like with other 2 element beams the gain is around 6 dBi. The feetpoint resistance for best gain is about 25 Ohm. A design for direct coax feeding with 50 Ohm has a bit less gain but more bandwith. The gain slopes down over the bandwith for about 2dB on a band with 300+ kHz.
The versions I designed are all for direct 50 Ohm feeding without any traps or coils. The probably most interesting types are the multiband solutions. Here you have 2 elements on each band combined with an unbeatable small size compared to interlaced yagis or logperiodics. And even the 40m versions can be handled by small towers and rotors which reduces your overall budget for the antenna system.
Questions and comments are most welcome!
73 Holger, DL7IO
dl7io @ qsl.net