mandag den 18. september 2017

144 MHz EME: New 4x6H Array

I've tried different antennas for EME on 144 MHz without much success. The antenna gain was 11-12 dBd. Sometimes an antenna received few signals from the Moon, but most of the time it received nothing. That was quite frustrating! I tried a sked with a big station (HB9Q) in order to get my first QSO, but the sked failed. He could not hear me, and I could not hear him.

To solve the problem, I decided to build a new antenna array with 15 dBd gain. This gain is generally considered as minimum for reliable EME communication on 144 MHz. LA3EQ Jan has succesfully used this antenna type for several years.

4 x 6-element yagi at OZ1BXM
My new antenna is 4x6H which is 4 stacked 6-element yagi-antennas with horizontal polarization. Each yagi is PA144-6-2 from Dual (YU1CF). The stacking distance is 2.40 m horizontal and 2.20 m vertical. All four antennas are mounted on an H-frame made of 1½" galvanized steel tubes. The 4-way power splitter was fitted using a homemade clamp. The box below the rotator contains a 1 kW coax-relay. The other box contains a HA8ET Extra-2 preamp (NF 0.5 dB). The horizontal rotator is Yaesu G-600 and the elevation rotator is Kenpro KR-550.

With this array, I hope to get my first EME QSO soon. Stay tuned!

Vy 73 from OZ1BXM Lars