Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by klubnl.pl (8.14.4/8.14.4/Debian-8+deb8u2) with ESMTP id wA68mTZn013324 for ; Tue, 6 Nov 2018 09:48:31 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1gJwxE-0003Dj-A2 for rs_out_1@blacksheep.org; Tue, 06 Nov 2018 08:43:20 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1gJwx6-0003Da-U8 for rsgb_lf_group@blacksheep.org; Tue, 06 Nov 2018 08:43:12 +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 4.91_59-0488984) (envelope-from ) id 1gJwx3-0002if-Qi for rsgb_lf_group@blacksheep.org; Tue, 06 Nov 2018 08:43:11 +0000 Received: from submission (posteo.de [89.146.220.130]) by mout01.posteo.de (Postfix) with ESMTPS id 9C292210C8 for ; Tue, 6 Nov 2018 09:43:05 +0100 (CET) X-DKIM-Result: Domain=posteo.de Result=Signature OK DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=posteo.de; s=2017; t=1541493787; bh=e3RyF+83dZN7OsbTss4C05E/Iaqn6OWIWHxCdVK/iiI=; h=Date:From:To:Subject:From; b=Bj/DqB9sWD5JGhRnvFEvpct2XccEnDE63DlYht0v/tfjsz8vZQ8ajnnH/P5cklorG 3C1RUqaSBsR+WqdwQqDagI5M6+72qEiigMHlblagW6t1GlgC1ciMnoSr68mWSzXtQh LmwEwbIJR0rAwRyW43c1kJe8jKmaE4FWNEsy1MBzkvw6bo2GKOEOYuG1F/bBDmOTTr 0Hev4Pn3Up/VtN+HVMDSszZm5iNalwbx1xidZoEWeepHHstZunWrOCkvRZ8M7JOTO7 xzJfuCW5j/KIZ9tsNFfhDEVn/dfccdnVmola7ZELd0+lXxL19aq5cjoDVJ/koBQPOO pr1aPbK6rUmtA== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 42q33D2XyTz6tmZ for ; Tue, 6 Nov 2018 09:43:01 +0100 (CET) Message-ID: <5BE15415.1000001@posteo.de> Date: Tue, 06 Nov 2018 09:43:01 +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: <5BE0C0CE.10008@posteo.de> <055b01d4757d$4c552fc0$e4ff8f40$@comcast.net> In-Reply-To: <055b01d4757d$4c552fc0$e4ff8f40$@comcast.net> X-Spam-Score: -2.3 (--) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see @@CONTACT_ADDRESS@@ for details. Content preview: Hi Jim, Yes, i will use the E field only. That is a first result from the pre-tests. Today the QRN is extremely low, very impressing! I'm getting 30 dB SNR from a 30 minute carrier integrated in one bin. Last night it was about 18 dB from the E field and nothing significant from the H field(s). The loops consist out of a single turn of 10mm diameter copper tube, about 1m diameter. The signal is coupled to the preamp by a ferrite transformer having about 100 turns. This works well on 8.27 kHz and maybe down to 4 kHz. But on lower frequencies this is not a good design. A multi-turn loop would be a better choice. Something for the future. [...] Content analysis details: (-2.3 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -2.3 RCVD_IN_DNSWL_MED RBL: Sender listed at http://www.dnswl.org/, medium trust [185.67.36.65 listed in list.dnswl.org] -0.0 T_RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -0.0 SPF_PASS SPF: sender matches SPF record 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 T_KAM_HTML_FONT_INVALID BODY: Test for Invalidly Named or Formatted Colors in HTML 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: 14522a7d8bfffcae5e92e35059f18ae1 Subject: Re: SLF: RE: A first step on SLF Content-Type: multipart/alternative; boundary="------------020605070005080409030408" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_40_50,HTML_MESSAGE autolearn=no version=2.63 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 This is a multi-part message in MIME format. --------------020605070005080409030408 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Hi Jim, Yes, i will use the E field only. That is a first result from the pre-tests. Today the QRN is extremely low, very impressing! I'm getting 30 dB SNR from a 30 minute carrier integrated in one bin. Last night it was about 18 dB from the E field and nothing significant from the H field(s). The loops consist out of a single turn of 10mm diameter copper tube, about 1m diameter. The signal is coupled to the preamp by a ferrite transformer having about 100 turns. This works well on 8.27 kHz and maybe down to 4 kHz. But on lower frequencies this is not a good design. A multi-turn loop would be a better choice. Something for the future. The high S/N of this morning promises that a distance of 7 km (i.e. twice) is realistic without problems. Also i notice that my E field RX does not have the maximum sensitivity at SLF. On quiet days, the background noise is not given by sferics. I can see that by checking the dropfactor of the noise blanker in vlfrx-tools. Its optimum value is at just about 3 %, which is unusual low. At 8.27 kHz it is between 10...20 %. So it would help to increase the antenna capacity or better the effective height, which is not so easy when beeing on a tree in about 20 m AGL... A few minutes ago i started transmitting a 30 character EbNaut message, just for the fun :-) 73, Stefan Am 06.11.2018 03:52, schrieb hvanesce@comcast.net: > > Hello Stefan, > > Good SNR at 3.5 km on the 1110 km band makes this a noteworthy day! > > During your future SLF pre-tests, and in the future tests that you > mentioned with the ground loop transmitter, will you be using the > E-field tree receiver? > > I've wondered if near-field polarizations and E/B ratios might be > different than expected with the electrically-small transmitting > antenna(s) in the ULF and SLF, including near trees. > > Your tree receiver SNR (~ 12dB at 424 uHz RBW, 3.5 km, 2.5ma) today > seems to suggest that terrain-induced E-field/B-field transduction and > polarization are not big factors; just wondering if you were planning > to check your loop receiver also (but I think you mentioned that the > loop would need modifications for SLF) > > Your 1110 km band signal well above QRM/QRN on your grabber for the > past 5 hours is a great sight. > > 73, > > Jim AA5BW > > *From:* owner-rsgb_lf_group@blacksheep.org > [mailto:owner-rsgb_lf_group@blacksheep.org] *On Behalf Of *DK7FC > *Sent:* Monday, November 5, 2018 5:15 PM > *To:* rsgb_lf_group@blacksheep.org > *Subject:* SLF: A first step on SLF > > Well, today, i did a first step into the ITU radio band 2, SLF > . > > Since 21:00 UTC i'm transmitting on the INV-L on *270.01 Hz*. The > antenna current is just 2.5 mA. The ERP is about 6 pW. > Almost nothing but anyway a trace becomes visible now on my RX on the > tree in 3.5 km distance > (http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html) > Of course this is a near field experiment. There, on the *1110 km > band*, the far field begins at a distance of 177 km. > > On the transmitter site i'm using the modified 5 kV mains transformer > that was used to produce 5 kV at 970 Hz. Now there is a series > capacitor of about 20 uF applied to the primary winding. Together with > internal reactances this maximises the peak of the fundamental > frequency of the output voltage. > > The goal of this first experiment is just to put the foot into this > part of the radio spectrum. And to do some pre-tests, trying to > optimise filter and blanker settings for future tests. > In the end i'm planning to work on that frequency from the ground loop > antenna, which is still in the near field, but anyway :-) > > 73, Stefan > --------------020605070005080409030408 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Hi Jim,

Yes, i will use the E field only. That is a first result from the pre-tests. Today the QRN is extremely low, very impressing! I'm getting 30 dB SNR from a 30 minute carrier integrated in one bin. Last night it was about 18 dB from the E field and nothing significant from the H field(s). The loops consist out of a single turn of 10mm diameter copper tube, about 1m diameter. The signal is coupled to the preamp by a ferrite transformer having about 100 turns. This works well on 8.27 kHz and maybe down to 4 kHz. But on lower frequencies this is not a good design. A multi-turn loop would be a better choice. Something for the future.

The high S/N of this morning promises that a distance of 7 km (i.e. twice) is realistic without problems.
Also i notice that my E field RX does not have the maximum sensitivity at SLF. On quiet days, the background noise is not given by sferics. I can see that by checking the dropfactor of the noise blanker in vlfrx-tools. Its optimum value is at just about 3 %, which is unusual low. At 8.27 kHz it is between 10...20 %. So it would help to increase the antenna capacity or better the effective height, which is not so easy when beeing on a tree in about 20 m AGL...

A few minutes ago i started transmitting a 30 character EbNaut message, just for the fun :-)


73, Stefan


Am 06.11.2018 03:52, schrieb hvanesce@comcast.net:

Hello Stefan,

 

Good SNR at 3.5 km on the 1110 km band makes this a noteworthy day!

 

During your future SLF pre-tests, and in the future tests that you mentioned with the ground loop transmitter, will you be using the E-field tree receiver?

 

I’ve wondered if near-field polarizations and E/B ratios might be different than expected with the electrically-small transmitting antenna(s) in the ULF and SLF, including near trees.

 

Your tree receiver SNR (~ 12dB at 424 uHz RBW, 3.5 km, 2.5ma) today seems to suggest that terrain-induced E-field/B-field transduction and polarization are not big factors; just wondering if you were planning to check your loop receiver also (but I think you mentioned that the loop would need modifications for SLF)

 

Your 1110 km band signal well above QRM/QRN on your grabber for the past 5 hours is a great sight.

 

73,

 

Jim AA5BW

 

 

 

 

 

 

From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of DK7FC
Sent: Monday, November 5, 2018 5:15 PM
To: rsgb_lf_group@blacksheep.org
Subject: SLF: A first step on SLF

 

Well, today, i did a first step into the ITU radio band 2, SLF.

Since 21:00 UTC i'm transmitting on the INV-L on 270.01 Hz. The antenna current is just 2.5 mA. The ERP is about 6 pW.
Almost nothing but anyway a trace becomes visible now on my RX on the tree in 3.5 km distance (http://www.iup.uni-heidelberg.de/schaefer_vlf/DK7FC_VLF_Grabber2.html)
Of course this is a near field experiment. There, on the 1110 km band, the far field begins at a distance of 177 km.

On the transmitter site i'm using the modified 5 kV mains transformer that was used to produce 5 kV at 970 Hz. Now there is a series capacitor of about 20 uF applied to the primary winding. Together with internal reactances this maximises the peak of the fundamental frequency of the output voltage.

The goal of this first experiment is just to put the foot into this part of the radio spectrum. And to do some pre-tests, trying to optimise filter and blanker settings for future tests.
In the end i'm planning to work on that frequency from the ground loop antenna, which is still in the near field, but anyway :-)

73, Stefan

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