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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