Message-ID: <58544F7A.8020606@posteo.de>
Date: Fri, 16 Dec 2016 21:32:58 +0100
From: DK7FC <selberdenken@posteo.de>
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3
MIME-Version: 1.0
To: rsgb_lf_group@blacksheep.org
References: <44960D15E9F74D8DBBE05E8A24298450@AGB> <1422413C99FE494EA95C4A94103353A8@AGB> <5670AA40.7020206@posteo.de>
In-Reply-To: <5670AA40.7020206@posteo.de>
Subject: Re: LF: DK7FC remote forest grabber now running /1 year
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org
Status: O

Hi all,

Time is running! My remote tree grabber is now on the air since 1 year. 
It has started with a single channel MF receiver (loop antenna). 
Meanwhile it has grown to a RDF grabber with two loops on MF and and VLF 
grabber with one loop and precise PPS+MNEA timing. So there are two 
stereo vorbis streams running. I estimate the availability has been 
about 95% during that year. The system is exclusively solar powered and 
uses 3x 18 Ah lead gel batteries.
Several 1000 WSPR decodes have been made from that system on MF. A few 
EbNaut decodes were made on VLF, as well as spectrograms.

http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_remote_Grabber.html
http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html

Whos know what will be in one year but i am optimistic to run it for 
another year and maybe i can add some more stuff there...

73, Stefan


Am 16.12.2015 01:03, schrieb DK7FC:
> 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
>