New project in progress:
4x9 elements 2,5 wl array
After few years of honored service (more than 50 new EME initials worked on six!) the 4x7jxx6 array is going to be replaced with a more performing set up.
The new monster will be strictly optimazed for EME traffic and it will use 4x9 elements home brew antennas built by Sandro I0JXX, 15 meter long boom yagi.
·
Array composed by 4 x 9 elements 2,5 wl antennas
·
Extimated gain on free space 18.8 dbd (20.92
dbi)
·
Extimated gain with ground gain 23.8 dbd
(25.92 dbi)
·
Center of the double "H" placed at 22 meter above ground
·
Horizontal spacing 10 meter
·
Vertical spacing 10 meter
·
First lobe on H-plane at about 3,8°, second lobe at about
12°
· Secondary lobe on E-Plane at -18 db
· Average front to back ratio 25 db
As you can notice, the gain will be impressive and the array will have a very clean pattern and optimal front to back ratio.
It will be the second largest EME array for 50 Mhz in the world!
But as you know, big antennas need big tower... so I decided to ask to I6UNR Rocco Angelucci to project and build a strong tower.
And Rocco made a masterpiece! A tower 21 meter high, 90 centimeter side, self supporting with antennas up to the top even with winds blowing up to 70 km/h!
In these pictures, taken during last Pescara ham trade-fair, the stacking distance is only 7,40 meter horizontal and 6 meter vertical.
But the real advantage is the H to support the four antennas: both the horizontal and the vertical masts are telescopic and they permit to adjust the stacking distance from 7,5 meter up to 11 meter!
Notice the mast also: 150 mm diameter!
Another great solution is the elevation system: it use an electric winch capable to elevate the antennas up to... 180 degress! So it will be possible to turn the antennas upside down, a great improvement when I'll have to do ordinary maintenance to upper antennas! The elevation control is monitored by an optical device.
On May 6th 2006 the new tower and its optionals has been delivered by Rocco to my QTH.
Now I can start to prepare the base and the concrete to set it up!
I still hope to be ready in summer 2006... but free time is very spare...
Fingers crossed!
More details in the future.