Return-Path: X-Spam-DCC: paranoid 104; 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=-0.2 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_40_50,HTML_MESSAGE,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 t5OKpb0r025812 for ; Wed, 24 Jun 2015 22:51:37 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Z7raS-0006II-HI for rs_out_1@blacksheep.org; Wed, 24 Jun 2015 21:48:00 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Z7raS-0006I9-6K for rsgb_lf_group@blacksheep.org; Wed, 24 Jun 2015 21:48:00 +0100 Received: from mx02.posteo.de ([89.146.194.165]) by relay1.thorcom.net with esmtps (TLSv1.2:DHE-RSA-AES256-GCM-SHA384:256) (Exim 4.85) (envelope-from ) id 1Z7raQ-0000FG-4G for rsgb_lf_group@blacksheep.org; Wed, 24 Jun 2015 21:47:59 +0100 Received: from dovecot04.posteo.de (unknown [185.67.36.27]) by mx02.posteo.de (Postfix) with ESMTPS id 988E525C0095 for ; Wed, 24 Jun 2015 22:47:56 +0200 (CEST) Received: from mail.posteo.de (localhost [127.0.0.1]) by dovecot04.posteo.de (Postfix) with ESMTPSA id 3mGxPm21nrzFpWD for ; Wed, 24 Jun 2015 22:47:56 +0200 (CEST) Message-ID: <558B177B.8020104@posteo.de> Date: Wed, 24 Jun 2015 22:47:55 +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: <8D27C7D3E7D6748-14A8-F71B3@webmail-vm149.sysops.aol.com> <31A204DF57314D5081D5DF2FAEACCDDB@White> In-Reply-To: <31A204DF57314D5081D5DF2FAEACCDDB@White> X-Scan-Signature: a44b221381f32eba3e5127fadf77bc3d Subject: Re: LF: 476.181 kHz from indoor loop Content-Type: multipart/alternative; boundary="------------060403040904010303070000" 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: 3526 This is a multi-part message in MIME format. --------------060403040904010303070000 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Hello Markus, Thanks. This is helpful for many people trying to improve their RX equipment. A QRPP beacon! Don't we have a nice hobby?!! :-) 73! Stefan PS: Tomorrow ordering parts for a stereo MF RX! Am 24.06.2015 21:07, schrieb Markus Vester: > Hi Mauro, > this is a single turn loop, around 3.5 m wide and 3 m high, now > consisting of the braid of a piece of RG-216 coax cable. Required > capacitance for 475 kHz is 7.1 nF, made from five 33nF FKP capacitors > from the junk box, plus a couple of styroflex for fine tuning. It's > fed through a small ferrite toroid, 32 turns primary, 4 secondary. > Loop resistance at MF is about 0.57 ohm (Q~83), presumably largely > affected by losses from the nearfield environment (reinforced walls, > house wiring, etc). Using 35 W RF the loop current is 7.8 A. Some pics > of the former LF loop tests (32 A, 250 uW) are at > http://df6nm.bplaced.net/LF/Indoor_Loop/ . > The purpose of this experiment is mainly to be able to provide > a signal for receiver testing, which (unlike my Marconi) can be left > on air during unfavourable weather. But it's really inefficient: An > old ENI broadband linear amplifier converts 140 W DC into 35 W of > RF, of which only ~ 2 mW are radiated. > Yes it works also for WSPR - a couple of nights ago I did get spotted > by DK7FC, F59706 and SP5XSB. During the daytime the range would be > much shorter, and the signal is definitely too weak for a decode in > Heidelberg. > Best 73, > Markus (DF6NM) > > *From:* IK1WVQ Mauro > *Sent:* Wednesday, June 24, 2015 7:30 PM > *To:* rsgb_lf_group@blacksheep.org > ; rsgb_lf_group@blacksheep.org > > *Subject:* Re: LF: 476.181 kHz from indoor loop > > very interesting for WSPR tests ! > > few questions: > > - mono-turn or multi-turn ?? > - what are you using for match to TX ??? > > many thanks and > 73 de Mauro IK1WVQ > > > At 12:11 24/06/2015, Markus Vester wrote: > >I am currently running a DFCW-60 beacon on 476.181 kHz, using the > >same 10m^2 indoor transmit loop as previously on LF. With 35 Watts > >of RF input, estimated radiated power is around 2 mW, with lobes > >pointing west and east. > > > >The daytime groundwave signal is visible in the bottom panel of the > >DK7FC MF grabber. Going by the CCIR plots for 3 mS/m conductivity, > >the groundwave attenuation for this distance would be about 23 dB in > >excess off lossless 1/r propagation, resulting in approximately 0.2 > >uV/m in Heidelberg. > > > >Best 73, > >Markus (DF6NM) > > > > > > --------------060403040904010303070000 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Hello Markus,

Thanks. This is helpful for many people trying to improve their RX equipment. A QRPP beacon!

Don't we have a nice hobby?!! :-)

73!
Stefan

PS: Tomorrow ordering parts for a stereo MF RX!



Am 24.06.2015 21:07, schrieb Markus Vester:
Hi Mauro,
 
this is a single turn loop, around 3.5 m wide and 3 m high, now consisting of the braid of a piece of RG-216 coax cable. Required capacitance for 475 kHz is 7.1 nF, made from five 33nF FKP capacitors from the junk box, plus a couple of styroflex for fine tuning. It's fed through a small ferrite toroid, 32 turns primary, 4 secondary. Loop resistance at MF is about 0.57 ohm (Q~83), presumably largely affected by losses from the nearfield environment (reinforced walls, house wiring, etc). Using 35 W RF the loop current is 7.8 A. Some pics of the former LF loop tests (32 A, 250 uW) are at http://df6nm.bplaced.net/LF/Indoor_Loop/ .
 
The purpose of this experiment is mainly to be able to provide a signal for receiver testing, which (unlike my Marconi) can be left on air during unfavourable weather. But it's really inefficient: An old ENI broadband linear amplifier converts 140 W DC into 35 W of RF, of which only ~ 2 mW are radiated.
 
Yes it works also for WSPR - a couple of nights ago I did get spotted by DK7FC, F59706 and SP5XSB. During the daytime the range would be much shorter, and the signal is definitely too weak for a decode in Heidelberg.
 
Best 73,
Markus (DF6NM)

Sent: Wednesday, June 24, 2015 7:30 PM
Subject: Re: LF: 476.181 kHz from indoor loop

very interesting for WSPR tests !

few questions:

- mono-turn or multi-turn ??
- what are you using for match to TX ???

many thanks and
73 de Mauro IK1WVQ


At 12:11 24/06/2015, Markus Vester wrote:
>I am currently running a DFCW-60 beacon on 476.181 kHz, using the
>same 10m^2 indoor transmit loop as previously on LF. With 35 Watts
>of RF input, estimated radiated power is around 2 mW, with lobes
>pointing west and east.
>
>The daytime groundwave signal is visible in the bottom panel of the
>DK7FC MF grabber. Going by the CCIR plots for 3 mS/m conductivity,
>the groundwave attenuation for this distance would be about 23 dB in
>excess off lossless 1/r propagation, resulting in approximately 0.2
>uV/m in Heidelberg.
>
>Best 73,
>Markus (DF6NM)
>
>


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