They exhibit good gain, Ta and G/T figures when compared to other offerings of the same boom length (especially the 12 element version) ... and do it with a 50 ohm feed point ... and with very wide SWR and gain bandwidths! This combination (and the RS suffix!) piqued my interest, but a Google search did not bring much joy (despite, as it turns out, that the idea for these Yagis was developed more than 2 years ago).
Coincidentally, yesterday Vladimir UR5EAZ sent me an e-mail pointing to the Russian "VHFDX - Forums" web site and a link to download the pertinent antenna analysis program files:
http://www.vhfdx.ru/faylyi/view-details ... /ant-ua9tc
(click on the USA/UK flag symbol to translate to English)
Opening the .nec antenna files with 4nec2 displayed an exceptionally clean radiation pattern which is clearly the reason for the good characteristics shown in the VE7BQH G/T Chart and should mean good receive performance in our increasingly RF polluted urban environments: Further examination of the geometry in the files showed the "secret" of the performance was the effect of a U-shaped reflector element. This u-shaped reflector theme is carried into the antenna name ... e.g. UA9TC 11RS where RS = Reflector Staple (or Staple Reflector in English grammar). No, nothing to do with my callsign suffix!
The shortest of these Yagis (the UA9TC 11RS as shown above) has a boom length of 6.2 meters which is fairly easily handled. The 50 ohm driven element feed point impedance can be conveniently fed with a split dipole and "ferrite" balun or sleeve balun, or made as a folded dipole to step the feed impedance up to 200 ohms for use with a 4:1 halfwave coax balun to reduce static pick up (which is probably as good a reason as any to go with the folded dipole driven element on any Yagi?)
There is some discussion about Boris' designs at:
http://translate.google.co.nz/translate ... 6prmd%3Div
... including his latest release today of a 17 element monster on a 11.4 meter long boom.
Perhaps these Yagis are worthy of consideration for your next antenna project?
![Cool 8)](./images/smilies/icon_cool.gif)
73, Bob ZL1RS