Cross-Yagis for EME Cross-Yagis for Terrestrial and Satellite Work

4x14-(28)-Element

Cross-Yagi

28-Ohm-DK7ZB

 

built by

Chris

PA2CHR

4x20-El.-28-Ohm-X-pol at Z3/PA2CHR

The 11-El.-DK7ZB-OWL-Yagi as 4x22-El.-X-pol Group

Built by Wojtek,

SP2FOW

His comments:

"I have to say that the antenna exercise is great. On the moon I hear stations with reports similar, and sometimes better than working stations with longer antennas different design"

 

19-El.-X-Rope-Yagi by

Henk,  PA0EME

 

Stairway to heaven!

There are two reasons for polarization rotations of the signal on the path eath-moon-earth:

1. Geometric Rotation (or Spatial Polarization), shown on the picture right.

2. Faraday Rotation, caused by the ionosphere.

For more information about these problems look on the interesting site of Ian, G3SEK:

http://www.ifwtech.co.uk/g3sek/eme/pol4.htm

For EME a clever switching system from IK2UWL is shown at the left picture. This system was used at the EME-expedition CE0Y/DK2ZF in October 2010.

For transmitting always circular polarization is used. The two Yagis (are Yagi.groups) are coupled with the 2.way splitter from the lines L1 and L2.

For receiving the H/V-relay, switched by hand, is set for the best received signal strength. Most of the times only one polarization gives a detectable signal on the WSJT-screen.

A better method is, to couple the two receiving coax lines to two preamps and two computers, on both running the WSJT-program.