new EME antennas

After operating for many years my home made  4 x 12el. DK7ZB antennas I decided to change them for a 4 x 9el./Xpol H/V antenna system made by DF7KF. Reason was the heavy polarization changing of the EME signals that I recognized over the past years. There are phases you do not hear anything with horizontal polarization over hours and days you hear signals with only horizontal polarization so what of weak that makes you believe something is wrong with your antennas.  My friend Udo/DK5YA offered me his 4×9 system for a nice price because he changed to a bigger system so I made the decision.

After some mechanical works the VSWR measurements at the system were very successful. Udo made a special and very professional set of adjusted phase coax lines for the connection of the H/V plane so system was fine at all. I know about that the 4x9el/Xpol has less 3-4 dB gain than my old 4 x 12el. but I hope I will have more advantage with making EME QSO’s also in Vpol. Running the system now for some weeks I can tell you that my thinking was proved in real situation. In the moment the QSO I made in V polarization are more than in H polarization.

Here are some measurements I made. VSWR is fine and RL also good.  Antenna photos are without phase lines and finished situation with phase lines.

DK5EW

Name is Erwin Witt, born 1962, working as technical service engineer in environmental test systems business. Ham radio hobby since 1980, main interests are VHF and EME operating.