Mechanical construction and test
After a few years collecting the antennas I finally could start building
my new stack for 432MHz: 8 yagi’s 21 elements from F9FT. My garden isn’t big enough
to build such an array but I get the permission of my father-in-law to use some
space at his home. On May 17th 2007, I build the stack and below you
can see the story. Together with my EME neighbor Rob, PE1ITR, we are going to
participate in the ARRL EME contest in October.
The workspace of my father
in law which I can use for building the stack and new antennas.
Construction of the
horizontal boom.
The rotator and support.
The horizontal and
vertical booms.
Only two yagis on place.
Again 3dB added hi.
Just one yagi to go.
Yes! The stack with the 8
yagis.
PE1RDP connecting the
feeders and a professional construction engineer is watching.
PE1ITR and PE1RDP are
checking the rotator.
“Is this connector still
ok?”
Even visitors from
Electrical test (sunnoise measurement)
Rob, PE1ITR, measuring the
phasing feeders.
A lot of work ….
Still a lot of work…
Rob, PE1ITR and Arno, PE1RDP,
working in a team.
Rotator and horizontal
boom ready.
Rob is connecting the
power splitters.
Stack almost ready for
action.
Our final part, connection
the phase feeders to the splitters.
After working a whole day,
finally ready.
Pointing to the cold sky,
just before sunset.
The ARRL EME contest 27/28 October 2007
Our stack almost there to
hit the moon.
Some feeders and control
wires from shack to stack.
The 8x21 ready for action!
Rob - PE1ITR – repairing
his PA with superglue.
Waiting for moonrise (and
beer to celebrate our first qso)
Breakfast after (almost)
no sleep .....
TX feeder (7/8"), RX
feeder (Aircom+) and elevation control wires.
The antenna worked, we
made several nice qso’s and could even hear our own echos in cw.
Building new 70cm yagis in the winter of 2007/2008.
The dipoles ready on the
garden table.
The holes drilled in the
boom.
Waiting when the rain will
stop …
Rain didn’t stop, yl not
at home, so antenna could dry inside the house.
Ready for electrical test.
Now v-pol.
Yagis now h-pol for eme test.
Building a new stack with 4 yagi’s 4x7wl DJ9BV (January 2009)
The 4 yagis, old, dirty,
without dipoles. But for free !
Just a quick sunnoise
measurement
But first making dipoles
with 1 4 balun
Dipoles in the a IP54
waterproofed box
A lot of qrm up till s9 so
EME impossible? No, just ask your neighbor to switch off his 433MHz (LPD)
clock…
As you can see, 4 yagis in
a 2x2 box are small, without driving your neighbors crazy.
Improving 16 elements DK7ZB 70cm yagis (spring 2010)
Temporary construction,
grounded to boom. Necessary for good match!
Detail of this match
After some experiments …
… better results
Both yagi’s waiting for
“antenna weather”
Change connector from N to
7/16
So … from N ….
… to 7/16
Both yagis 7/16 with
improved ground by using aluminum
Telefunken SV 5379 Solid State PA for 70cm (July 2010)
A relay, some fuses and
surge guards are the only modifications inside the power supply
And outside a fan and a
power switch
Controller inside and LEDs
at the front of the PA
The controller in detail
The controller in place of
the
Telefunken SV 5379, the
front
Not a good idea. The fans
are too close to the heat sink. Too less airflow for sufficient cooling.
Fans now in good position.
Enough airflow in the
“tunnel”
Building another 2 yagis for the four-group
Phasing feeders. Now ˝”
lcf1250 by RFS. It was Ecoflex 10
N connector on one side ….
And 7/16 Andrews at the
other side
Attenuation measurement
Using qrp transmitter
Measured max 0.19dB
(inclusive connectors and 2 adaptors)
Mechanical construction of the yagi’s (February 2011)
Passive elements almost
ready
Nice weather: 12 deg
Centrigrade, sunny and no wind. Almost spring.
Mechanical test passed
New material under deep
blue sky
Build the array on the roof (March 2011)
First: remove all 144MHz
yagi’s
The yagi’s are in place,
feeders aren’t connected yet.
After a whole day working,
all the stuff is working. Just before sunset.
Even full elevation is
possible
The four yagi’s in a small
box
The new material shiny in
the spring sun
I can measure about 8dB
sunnoise.