I've started experimenting with this antenna type because it was proposed by some people as a good sollution as long as we are in Receiving mode. Here's what I found.

We had already tried this type of Antenna but made an error in the calculations. Since data we gathered is thus worthless, we should redo all things about this antenna type.

The antenna should be a <m>lambda / 4</m> antenna and thus Wavelength is ~ 275.04 mm, a quarter wavelength is ~ 68,76 mm.

Thus the antenna should look like this:

The lenght of the antenna should be lambda/4, the lenght of the ground-wires should also be.

German wikipedia (article Groundplane Antenna 2011-01-01, 3am says, the ground wires should be in a 135 degree angle from the antenna wire to match 50 Ohms.

TODO: test the antenna.

I found out that comercial antennas with high gain often are very long like in 1.2 to 3.5 Meters. In the antenna Manuals (eg see [[http://www.scribd.com/doc/20515944/Kathrein-Antennas|Different Types of Kathrein Antennas||, in the section VPol Omnidirectional Antenna 1087 to 1093 Mhz) they talk about decouploed Dipoles. As far as i get it, that means that you put more than one Dipole into an Antenna. To make the antenna not have different gains for different directions, the dipoles are stacked. Since the signal is vertically polarized, the antenna won't become direction-dependent if the dipoles are above each other.

It's not clear if that also works for groundplane antennas.

Need plan to build that.