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Copyright F1HDI - last update Jan 25th 2009

Happy New Year and have a lot of fun on EME

The last Dxpedition 5R8EM is now history, with a lot of knowhow and still a lot of items to improve

 

For this Expedition, the decision taken was to use ‘brute force’ ie max gain in H polarisation compatible with our traveling constraints, opposite strategy than the one used for 6V7A and J79DI which was 2x cross yagis.

 

The choice of 4 yagis , rather than 2 long ones is a key factor for the necessary mast height, but still questionable in term of weight/easiness to erect.

 

For 4 short yagis, the center of the H-frame can be as low as 4 meters whereas it should be more for dual long yagis

 

The central horizontal mast can be metallic for 4x where is should be insulated in the yagi vicinity for 2x cross yagy

 

Noise pickup at low elevation angles is less for the 4x than the 2x

 

In all cases, cross polarity means insulated parts near the yagis in the antenna frame and coax cables must be wired at the back of the antennas and not following the boom upward.