| Cross-Yagis for EME | Cross-Yagis for Terrestrial and Satellite Work |
New 70-cm-Yagis: 27-El.-hor+23-El-ver by Chris, PA2CHR
August 2015: EME-DXpedition HV0A with 2x12-El.-X-pol-DK7ZB-Yagis (built by PA2CHR)
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4x14-(28)-Element Cross-Yagi 28-Ohm-DK7ZB
built by Chris PA2CHR |
4x20-El.-28-Ohm-X-pol at Z3/PA2CHR
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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" |
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19-El.-X-Rope-Yagi by Henk, PA0EME
Stairway to heaven! |
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| 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: |
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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. |