Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-ma01.r1000.mx.aol.com (Internet Inbound) with ESMTP id 95C0038000086; Sun, 1 Apr 2012 17:48:41 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1SEScj-0007Dt-2k for rs_out_1@blacksheep.org; Sun, 01 Apr 2012 22:47:45 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1SESci-0007Dk-CE for rsgb_lf_group@blacksheep.org; Sun, 01 Apr 2012 22:47:44 +0100 Received: from relay.uni-heidelberg.de ([129.206.100.212]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1SEScg-0000UT-KR for rsgb_lf_group@blacksheep.org; Sun, 01 Apr 2012 22:47:44 +0100 Received: from freitag.iup.uni-heidelberg.de (freitag.iup.uni-heidelberg.de [129.206.29.204]) by relay.uni-heidelberg.de (8.14.1/8.14.1) with ESMTP id q31LlfSm006351 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Sun, 1 Apr 2012 23:47:42 +0200 Received: from [129.206.22.206] (pc206.iup.uni-heidelberg.de [129.206.22.206]) by freitag.iup.uni-heidelberg.de (8.12.11.20060308/8.11.2) with ESMTP id q31LlepG030456 for ; Sun, 1 Apr 2012 23:47:40 +0200 Message-ID: <4F78CCE0.5050906@iup.uni-heidelberg.de> Date: Sun, 01 Apr 2012 23:47:12 +0200 From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= 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: In-Reply-To: X-Spam-Score: 1.4 (+) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,RATWARE_GECKO_BUILD=1.426 Subject: Re: LF: LOPTs Content-Type: multipart/alternative; boundary="------------090804090100050209050200" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.6 required=5.0 tests=HTML_20_30, HTML_FONTCOLOR_UNSAFE,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 x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:446642432:93952408 x-aol-sid: 3039ac1d60094f78cd3923df X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. --------------090804090100050209050200 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Hi Roger, Well, they are not as suitable as i expected. Just a few kV can be generated and applied to the wire. But that's fine for local tests. I didn't measure the L but rather tried to find a resonance. I took two 1 nF capacitors and a 50 Ohm resistor in series to make an equivalent circuit of my antenna for tests in the shack. I built a class D PA out of the transformer, running at low input voltage and tried to find the resonance. But there was no clear resonance. The output waveform looks very different to a sine wave :-) Probably this is due to internal winding capacitances, no idea. At least i spend a lot of time and do not want to spend even more time on the LOPT project. A few weeks ago i tried some local tests with WOLF10 and got a decode in 950m distance, which is close in the near field, so not really exciting. I just want to go on a bit with these tests but i won't go on much longer with the tests. The standard QRSS or DFCW or MFSK analog modes, readout by a human is just the best in my opinion. 73, Stefan Am 01.04.2012 22:35, schrieb Roger Lapthorn: > Stefan et al, > > Not being too familiar with LOPTs what inductance are the windings? > Are there particular non-encapsulated types that would be more > suitable for compact loading coils for lower powered 8.97kHz E-field > TX antennas? > > 73s > Roger G3XBM > > -- > http://qss2.blogspot.com/ > http://g3xbm-qrp.blogspot.com/ > http://www.g3xbm.co.uk > https://sites.google.com/site/sub9khz/ > > --------------090804090100050209050200 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Hi Roger,

Well, they are not as suitable as i expected. Just a few kV can be generated and applied to the wire. But that's fine for local tests. I didn't measure the L but rather tried to find a resonance. I took two 1 nF capacitors and a 50 Ohm resistor in series to make an equivalent circuit of my antenna for tests in the shack. I built a class D PA out of the transformer, running at low input voltage and tried to find the resonance. But there was no clear resonance. The output waveform looks very different to a sine wave :-) Probably this is due to internal winding capacitances, no idea. At least i spend a lot of time and do not want to spend even more time on the LOPT project.
A few weeks ago i tried some local tests with WOLF10 and got a decode in 950m distance, which is close in the near field, so not really exciting. I just want to go on a bit with these tests but i won't go on much longer with the tests. The standard QRSS or DFCW or MFSK analog modes, readout by a human is just the best in my opinion.

73, Stefan



Am 01.04.2012 22:35, schrieb Roger Lapthorn:
Stefan et al,

Not being too familiar with LOPTs what inductance are the windings? Are there particular non-encapsulated types that would be more suitable for compact loading coils for lower powered 8.97kHz E-field TX antennas?

73s
Roger G3XBM

--
http://qss2.blogspot.com/
http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
https://sites.google.com/site/sub9khz/


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