Return-Path: X-Spam-DCC: paranoid 1170; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-0.7 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, RATWARE_GECKO_BUILD autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id tABLU0CK019803 for ; Wed, 11 Nov 2015 22:30:00 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Zwcuu-0008Td-Rt for rs_out_1@blacksheep.org; Wed, 11 Nov 2015 21:26:56 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Zwcuu-0008TU-I3 for rsgb_lf_group@blacksheep.org; Wed, 11 Nov 2015 21:26:56 +0000 Received: from mout01.posteo.de ([185.67.36.65]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.86) (envelope-from ) id 1Zwctl-0002ST-DA for rsgb_lf_group@blacksheep.org; Wed, 11 Nov 2015 21:26:55 +0000 Received: from dovecot03.posteo.de (dovecot03.posteo.de [172.16.0.13]) by mout01.posteo.de (Postfix) with ESMTPS id 7712B20A0D for ; Wed, 11 Nov 2015 22:25:32 +0100 (CET) Received: from mail.posteo.de (localhost [127.0.0.1]) by dovecot03.posteo.de (Postfix) with ESMTPSA id 3nwzcX2wTXz5vN0 for ; Wed, 11 Nov 2015 22:25:32 +0100 (CET) Message-ID: <5643B24C.6090200@posteo.de> Date: Wed, 11 Nov 2015 22:25:32 +0100 From: DK7FC 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: <3EEE0BD431264721BAD95B0598D0A459@White> <55AA13A5.5090300@posteo.de> <55F6E63E.1090407@posteo.de> <5609BBA4.5030007@posteo.de> <561AD16F.2010506@posteo.de> <56226BE5.5060707@posteo.de> <56279657.2050205@posteo.de> In-Reply-To: <56279657.2050205@posteo.de> X-Scan-Signature: 61577e2058c0d3bf1737d7de6ed6eb16 Subject: Re: LF: Ongoing work on the forest grabber Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false X-Scanned-By: MIMEDefang 2.56 on 10.1.3.10 Status: O X-Status: X-Keywords: X-UID: 4979 Hi all, Just a small report again. Did you ever solder into a tree, 18m above ground level? I've added a deep discharge protection circuit including bash scripts for the Raspi today. It was a sunny afternoon. Soldering was easy. I took my soldering iron from my solder station at home. It is normally running at 24 VAC and has a temperature regulation circuit. Amazon offers 3 EUR cheap DC/DC up-converters. So i generated 16 V DC out of the batteries to feed the iron. This is enough to comfortably solder /p !! https://dl.dropboxusercontent.com/u/19882028/MF/20151111_160546.jpg Now there are two missing steps to get the system ready for a permanent MF/LF/VLF streaming: The battery charger and the solar module(s). Hopefully this can be finished very soon. 73, Stefan Am 21.10.2015 15:42, schrieb DK7FC: > Hi all, > > The autumn makes progress: > https://dl.dropboxusercontent.com/u/19882028/MF/20151020_164144.jpg > Finished the installation of the accus on the tree: > https://dl.dropboxusercontent.com/u/19882028/MF/20151020_164131.jpg > Coupled the first MF RX-loop: > https://dl.dropboxusercontent.com/u/19882028/MF/20151020_173822.jpg > Run the first MF stream from this location ever!: > https://dl.dropboxusercontent.com/u/19882028/MF/stream2_86.jpg > > The first impression isn't so good, i must admit. But the spectrogram > settings are not optimal. The RX' bandfilter obviously doesn't like > the small resonance curve of the loop, i.e. there is a nerving visible > ripple inside the band. > Currently, the resonance peak is at 479.9 kHz: > https://dl.dropboxusercontent.com/u/19882028/MF/20151020_180246.jpg I > already modified the C-pack to move the resonance peak down to 475 kHz. > > Some of the QRM traces are coming from the far field. I know these > traces from the city grabber and from the garden grabber and now even > from this location, so it cannot be local. > It quickly became cold during the time i monitored the band so i > haven't had enough time to wait for WSPR traces. DH5RAE was the only > active station to that time and the "duty cycle" wasn't really high ;-) > Anyway, it's a good progress and i'm looking forward to the next tests... > > 73, Stefan > > Am 17.10.2015 17:40, schrieb DK7FC: >> Hi all, >> >> Despite mostly overcast wx i spend 3 hours into the tree today. Now >> the first of 3 accus is on the board, still not used. Also, the >> (mono-) MF-RX is up and a shielded USB-soundcard is connected to the >> Raspi. >> >> Further i have completed the installation of the first loop, beaming >> about 120/300 deg. It is a single turn, circular(ish) loop with a >> diameter of about 5m. The feed point (the highest point of the loop) >> at about 15m above ground. >> Measurements with a modified MFJ259B show that i need 14 turns on a >> coupling transformer, when 2 primary turns are used, i.e. the loop >> losses (at 475 kHz) is about 1 Ohm. I tried to find the C that is >> needed to resonate the loop at 475 kHz but unfortunately my C-network >> (0...1000nF + 1nF + 2.2nF + 4.7nF, switchable) does not cover the >> value prcisely, it is just below 4.7 nF and above 4.2 nF. Next time... >> Some images, as usual: >> https://www.dropbox.com/sh/hjnkp3a60fyqk9v/AADRX9Hv2nAu7jYdzHHdRJ4Ja?dl=0 >> (nothing special, just to share some RF stuff :-) ). >> >> 73, Stefan >