Congratulations Stefan
Great job !! Beautiful site
>> -Further crazy ideas...
That's my favourite :-)
I know Tx is (actually) not an option for a solar powered site
But ... At that height may be a vertical top loaded, top feeded antenna
like the setup I'm using may be an option ??
High efficency would make it possible to run it at very low power levels
under 20dBm as I have tested last week. So you can provide to ham community
QRO signals for suboptimal Rx and Dx, and QRP signals for high efficient Rx
Unfortunately Tx and grabbers are not compatible in a common site
But seems that you bought the whole forest, didn´t you ? ;-)
73 de Luis
EA5DOM
-----Mensaje original-----
De: [email protected]
[mailto:[email protected]] En nombre de DK7FC
Enviado el: miércoles, 16 de diciembre de 2015 1:03
Para: [email protected]
Asunto: LF: DK7FC remote forest grabber now running
Hi all,
Finally my new remote forest grabber, version 2.0, is now active in JN49ik36!
There, in a radius of 1000m, there is no electricity. The new version uses the
new Raspberry Pi 2 which performs much better. The overall power consumption of
the system is below 3W. The stereo RF stream is stable and the CPU load is just
about 22%. There are 3 lead acid gel accus, 18 Ah each.
In the last weeks i finished the last important steps.
-Installed the (first) 50W solar module in an angle of 60 deg (winter
optimised)
-Installed the accu charger circuit which has a variable voltage limiting
depending on the accu temperature (PTC sensores installed) -Put the stereo MF
DC converter into the box -Painted the WLAN yagi in military green,
camouflage-antenne :-) -Installed scripts to track the battery voltage, WLAN
link level and CPU temperature
- Updated the grabbers website,
http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_remote_Grabber.html
So far, there is only one antenna on the tree. A loop for 630m, beaming NW/SE.
Seems to work well from what i saw so far. However there is still QRM coming
from the far field. Some QRM traces are visible on the DL3ZID grabber in > 500
km distance. Maybe there is some noise from the DC/DC converter, not sure. Will
check that later.
You can't imagine the feeling beeing up on the tree there. Its just peace and
freedom! Worth all the "effort".
Some images at
https://www.dropbox.com/sh/iogg0azyaezrg0y/AADJGvxaq4OEJuNYZ2YyfP_Ca?dl=0
(beeing not happy with seafile as an alternative for dropbox. Will try owncloud
soon)
Next steps are:
-Building a second loop, orthogonal, for MF.
-Building an active antenna for LF/MF. A power saving model, running at 5V/1mA!
-Starting with first steps for 2200m!
-Installing a web-cam.
-Further crazy ideas...
73, Stefan
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