Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=0.0 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, HTML_MESSAGE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 X-Spam-DCC: MGTINTERNET: mailn 1170; Body=2 Fuz1=2 Fuz2=2 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by lipkowski.org (8.14.4/8.14.4/Debian-8+deb8u2) with ESMTP id v87NfnbM006162 for ; Fri, 8 Sep 2017 01:41:51 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1dq6Lw-0005VC-Mz for rs_out_1@blacksheep.org; Fri, 08 Sep 2017 00:36:56 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1dq6Lv-0005V3-Hw for rsgb_lf_group@blacksheep.org; Fri, 08 Sep 2017 00:36:55 +0100 Received: from mout02.posteo.de ([185.67.36.66]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1dq6Lr-0002Lc-7l for rsgb_lf_group@blacksheep.org; Fri, 08 Sep 2017 00:36:54 +0100 Received: from submission (posteo.de [89.146.220.130]) by mout02.posteo.de (Postfix) with ESMTPS id 6763D20B36 for ; Fri, 8 Sep 2017 01:36:47 +0200 (CEST) Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 3xpH0Z6SVPzytZ for ; Fri, 8 Sep 2017 01:36:46 +0200 (CEST) Message-ID: <59B1D80D.9090500@posteo.de> Date: Fri, 08 Sep 2017 01:36:45 +0200 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: <15e1104432f-c04-c80b@webjas-vac074.srv.aolmail.net> <599EB51C.1040204@posteo.de> In-Reply-To: X-Scan-Signature: 567a11ac6cfe1e88f3054745c06178fe Subject: Re: VLF: Carrier on 8270.00709 Hz Content-Type: multipart/alternative; boundary="------------000400070506020607060806" 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 2.75 Status: RO X-Status: X-Keywords: X-UID: 12548 This is a multi-part message in MIME format. --------------000400070506020607060806 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Hi Joe, Just as an inspiration for a VLF coil design, here's an image of the first coil of a stackable set of coils for VLF: http://www.iup.uni-heidelberg.de/schaefer_vlf/VLF/coil1.jpg I just finished to wind it. It has *172 mH*. A 2nd and a 3rd and a 4th and and and.. will be wound later. The advantage of that system is that i can tune to any frequency, without steps. Also it is much easier to repair than my large VLF coil for 2.97 kHz. It uses 0.25 mm diameter wire and is intended to be driven at 300 mA antenna current. The system will focus on frequencies < = 5.17 kHz. It took about 7 hours for the winding and 2 hours for preparing a construction to rotate it by a motor. With that single coil i could resonate to 17.5 kHz. But with a second one i will already be quite close to 8.27 kHz. With 4 of them i will already reach 5.17 kHz. And 6 of them could be fine for 2.97 kHz! Maybe i will build 8 of them to reach 2.17 kHz :-) The DC resistance of the single coil is 267 Ohm, so the losses will be 25 W per coil. Ah and the coil diameter is 0.3 m (average). The wire is hold in place by Kapton tape which is cheaply available from Amazon. 73, Stefan Am 07.09.2017 14:10, schrieb jcraig@mun.ca: > This is amazing, Paul. To copy < 0.00001 watts across > the pond with the carrier drifting about is an amazing feat. > The daytime signal is used because more atmospheric > noise is propagated at night? > > Unfortunately there is now a delay in getting the gps board but > better stability is certainly in the future. > > Thank-you for your efforts and monitoring. > > 73 > Joe VO1NA > > On Thu, 7 Sep 2017, Paul Nicholson wrote: > >> >> Joe VO1NA wrote: >> >>> Today the aerial was disconnected at 0950 utc >> >> Here's a non-coherent average over 8 days of 10:00 to 20:00 >> >> http://abelian.org/vlf/tmp/170907a.gif >> >> Impossible to do coherent sum with this many days, without >> GPS frequency lock. >> >> Not bad for 8uW ERP but it should do a lot better with a precise >> frequency. >> >> -- >> Paul Nicholson >> -- >> >> > --------------000400070506020607060806 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Hi Joe,

Just as an inspiration for a VLF coil design, here's an image of the first coil of a stackable set of coils for VLF: http://www.iup.uni-heidelberg.de/schaefer_vlf/VLF/coil1.jpg
I just finished to wind it. It has 172 mH. A 2nd and a 3rd and a 4th and and and.. will be wound later. The advantage of that system is that i can tune to any frequency, without steps. Also it is much easier to repair than my large VLF coil for 2.97 kHz.
It uses 0.25 mm diameter wire and is intended to be driven at 300 mA antenna current. The system will focus on frequencies < = 5.17 kHz.
It took about 7 hours for the winding and 2 hours for preparing a construction to rotate it by a motor.
With that single coil i could resonate to 17.5 kHz. But with a second one i will already be quite close to 8.27 kHz. With 4 of them i will already reach 5.17 kHz. And 6 of them could be fine for 2.97 kHz! Maybe i will build 8 of them to reach 2.17 kHz :-)
The DC resistance of the single coil is 267 Ohm, so the losses will be 25 W per coil. Ah and the coil diameter is 0.3 m (average).
The wire is hold in place by Kapton tape which is cheaply available from Amazon.

73, Stefan



Am 07.09.2017 14:10, schrieb jcraig@mun.ca:
This is amazing, Paul. To copy < 0.00001 watts across
the pond with the carrier drifting about is an amazing feat.
The daytime signal is used because more atmospheric
noise is propagated at night?

Unfortunately there is now a delay in getting the gps board but
better stability is certainly in the future.

Thank-you for your efforts and monitoring.

73
Joe VO1NA

On Thu, 7 Sep 2017, Paul Nicholson wrote:


Joe VO1NA wrote:

Today the aerial was disconnected at 0950 utc

Here's a non-coherent average over 8 days of 10:00 to 20:00

http://abelian.org/vlf/tmp/170907a.gif

Impossible to do coherent sum with this many days, without
GPS frequency lock.

Not bad for 8uW ERP but it should do a lot better with a precise
frequency.

--
Paul Nicholson
--



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