Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dk05.r1000.mx.aol.com (Internet Inbound) with ESMTP id 84CCB380000A2; Mon, 5 Sep 2011 08:34:03 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1R0YMS-0003nh-AA for rs_out_1@blacksheep.org; Mon, 05 Sep 2011 13:33:12 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1R0YMR-0003nY-AK for rsgb_lf_group@blacksheep.org; Mon, 05 Sep 2011 13:33:11 +0100 Received: from nm15-vm0.bullet.mail.sp2.yahoo.com ([98.139.91.208]) by relay1.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1R0YMO-00050y-7Q for rsgb_lf_group@blacksheep.org; Mon, 05 Sep 2011 13:33:11 +0100 Received: from [98.139.91.68] by nm15.bullet.mail.sp2.yahoo.com with NNFMP; 05 Sep 2011 12:33:00 -0000 Received: from [98.139.91.10] by tm8.bullet.mail.sp2.yahoo.com with NNFMP; 05 Sep 2011 12:33:00 -0000 Received: from [127.0.0.1] by omp1010.mail.sp2.yahoo.com with NNFMP; 05 Sep 2011 12:33:00 -0000 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 690355.15619.bm@omp1010.mail.sp2.yahoo.com Received: (qmail 18788 invoked by uid 60001); 5 Sep 2011 12:33:00 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s1024; t=1315225980; bh=5Y7npFDr+SXtoZqWtIcLBXJIsrOxgRhpy8ZMezZzlMs=; h=X-YMail-OSG:Received:X-Mailer:References:Message-ID:Date:From:Reply-To:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=mbxX4ihDAuZTnCQCH3vciHzWxOJIvnRsTTDsa7QJ457xvO+SUzDMiQ5uiLJJHPFVm25i07FIgfSggq0sdcrCyqleyRqnEGKKquS04RCyBHEUafuuWTxn1eFZ/HcvV7Cr9ohhWFdm1kgmtSvNfRZtbOou5ypPF8fGSQn3Vjrid08= DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=X-YMail-OSG:Received:X-Mailer:References:Message-ID:Date:From:Reply-To:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=hHpq3TT8ckKWJq6CdCOXwKjk+0hrWHj+/MmGH+s5Gadyx7dSfNfe4j5XA/lE8d3t5X0Q/F4NWaJD1qJWzZC8kRcOokjdWWcHE2ptAdG7X4ADn37+DuyZjH02bFhUmV8+kRwSYgnBLNX4iNqzKSRq6ODnQI1a0TMDnwNHiFhvG7Y=; X-YMail-OSG: Ys6o8swVM1ld4ECr7oKFaZ4aaBC4Bw98WbvMSvHxJBKVAHx _6r.F3kWYYzpcA4m3d2V1mMFTk8gdAgF3pfUFhpB7Jz6EF_bZShwi9d.eXO2 c_ZfbCgerZHac85kLcA2qq6TcqXlnDF2f5ZQN60xgkYMcviNSVyPK3cwHYa9 _ObVZq9gXT2uqKbbCvYXU7yGRE43W8QanPsR41MQxxy29jlPVs_IBONKBSH5 tpQ0.lYvbo4QLZIK2Z5vEvSl8EHc_zEIH62rt51a1dlS4hMY_sqELl35k8uD bPc2X5yYOAs6kqxKDJF.bMYV2OHBxF1iJYLfCyJRIH8Kv6cbkA.J9u9uF8Xd dhYuVfiAC68_VLF73wJXqYhwJZOkhI2DxfLnTu2KHUt4DYBSrGw92pd3NiOc WT6TLFvGHllosCE80zJZyNrBXk6gFBLyY1QV2pDZQ1sqDxlXVdkRSO_avGZw DZ7HzX2Yin9_Qz02Nbbm.SCwusab7iLgYEP3WBwuaxAyMX8zAAZ9TKFr5P0n if_hyn23vvKix22G.c0_EfOpi52nJ7ypQmSQPKcs5eE_2FH8Lg16aHDJ8Hat bHVRDbR_fwYotG86RRjaMILVG7QFjvpE- Received: from [151.99.187.181] by web111901.mail.gq1.yahoo.com via HTTP; Mon, 05 Sep 2011 05:32:59 PDT X-Mailer: YahooMailWebService/0.8.113.315625 References: <4E64BEB6.7000002@iup.uni-heidelberg.de> Message-ID: <1315225979.12868.YahooMailNeo@web111901.mail.gq1.yahoo.com> Date: Mon, 5 Sep 2011 05:32:59 -0700 (PDT) From: Daniele Tincani To: "rsgb_lf_group@blacksheep.org" In-Reply-To: <4E64BEB6.7000002@iup.uni-heidelberg.de> MIME-Version: 1.0 DomainKey-Status: good (testing) X-Spam-Score: 1.4 (+) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,HTML_TINY_FONT=1.425 Subject: Re: LF: Loop vs. ferrite antenna tests... Content-Type: multipart/alternative; boundary="0-1320451019-1315225979=:12868" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=1.0 required=5.0 tests=FORGED_YAHOO_RCVD,HTML_20_30, HTML_MESSAGE,TO_ADDRESS_EQ_REAL 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: 1:2:449254272:93952408 X-AOL-SCOLL-URL_COUNT: 1 X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-d021.1 ; domain : yahoo.com DKIM : fail x-aol-sid: 3039ac1db4094e64c1ba7620 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none --0-1320451019-1315225979=:12868 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable =A0=0AHello Stefan, LF,=0A=A0=0AI'm looking for a suitable preamp for my "c= oming sooner or later" tunable ferrite antenna (hopefully covering as much = as possible of LF band with a var. cap. plus some switchable additional cap= .). Any suggestions?=0A=A0=0ABest regards=0AD.=0A=0A=A0=0AFrom: Stefan Sch= =E4fer =0ATo: rsgb_lf_group@blacksheep.org= =0ASent: Monday, September 5, 2011 2:21 PM=0ASubject: LF: Loop vs. ferrite = antenna tests...=0A=0ALF,=0A=0AThere was no chance for me to TX in France t= his year but at least i did some useful comparisons with my single turn loo= p (1m diameter) and the ferrite antenna.=0A=0AMarkus/DF6NM did some CW beac= on transmissions on 136.5 kHz for me. The distance was 428 km (http://no.no= nsense.ee/qthmap/?qth=3DJN59NK&from=3Djn29od96).=0ABoth antennas were point= ing to DF6NM. The whole system was running on batteries and the distance be= tween antennas and netbook was sufficient. Anyway there was a noise pickup,= maybe by the local 20 kV line in some 10m distance.=0A=0ABest S/N for the = loop was achieved by using the preamp + a 10 dB attenuator. Without the att= enuator, the RX gets overloaded due to DCF39 which is still very strong the= re. Without the preamp, the noise floor is to close to the soundcard+RX noi= se it seemed. It was a relatively quiet morning, just some individual crack= s / QRN.=0A=0AThe ferrite antenna was used in combination with the same pre= amp (M0BMU design, 50 Ohm based), but without the attenuator.=0A=0AThe audi= ble performance of the ferrite antenna seems to be even slightly better tha= n with the loop. This is due to the smaller bandwidth (higher Q) of the fer= rite antenna that reduces the DCF and HGA levels even more. Markus was well= audible on both antennas! The S/N was about 20...23 dB in 3 Hz noise bandw= idth.=0A=0AA comparative spectrogram can be found at http://dl.dropbox.com/= u/19882028/LF/DF6NM%20in%20CW%20in%20JN29OD96.png=0AFirst one can see the f= errite antenna (slightly lower signal level but about same S/N) recording, = then the loop.=0ASpecLab was using a 10th order butterworth filter centered= to 137 kHz, with 2 kHz bandwidth. The noiseblanker was applied as well (9 = dB treshold).=0AAn audio file can be found here: http://dl.dropbox.com/u/19= 882028/LF/DF6NM%20in%20CW%20in%20JN29OD96.WAV=0AIt uses a 500 Hz CW filter = at 700 Hz AF. Except the filter and blanker, no further noise reduction is = applied.=0AI personally find the first part of the file better to copy. Thi= s is the ferrite antenna!=0A=0ATnx Markus/DF6NM for the test.=0A=0A73, Stef= an/DK7FC=0A=0APS:=0ACopied further stations:=0ADG3MDE : http://dl.dropbox.c= om/u/19882028/LF/DG3MDE.jpg=0ADF6NM at 35 dB S/N in 488 mHz: http://dl.drop= box.com/u/19882028/LF/DF6NM_QRSS-3.jpg (wrong locator in the capture) --0-1320451019-1315225979=:12868 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
 
Hello Stefan, LF,
 
I'm looking for a su= itable preamp for my "coming sooner or later" tunable ferrite antenna (hope= fully covering as much as possible of LF band with a var. cap. plus some sw= itchable additional cap.). Any suggestions?
 
Best regards<= VAR id=3Dyui-ie-cursor>
D.

 
From:= Stefan Sch=E4fer <schaefer@iup.uni-heidelberg.de>
<= SPAN style=3D"FONT-WEIGHT: bold">To: rsgb_lf_group@blacksheep.or= g
Sent: Monday, Septembe= r 5, 2011 2:21 PM
Subject: LF: Loop vs. ferrite antenna tests...

LF,

There was= no chance for me to TX in France this year but at least i did some useful = comparisons with my single turn loop (1m diameter) and the ferrite antenna.=

Markus/DF6NM did some CW beacon transmissions on 136.5 kHz for me. = The distance was 428 km (http://no.nonsense.ee/qthmap/?qth=3DJ= N59NK&from=3Djn29od96).
Both antennas were pointing to DF6NM. Th= e whole system was running on batteries and the distance between antennas a= nd netbook was sufficient. Anyway there was a noise pickup, maybe by the lo= cal 20 kV line in some 10m distance.

Best S/N for the loop was achie= ved by using the preamp + a 10 dB attenuator. Without the attenuator, the R= X gets overloaded due to DCF39 which is still very strong there. Without th= e preamp, the noise floor is to close to the soundcard+RX noise it seemed. = It was a relatively quiet morning, just some individual cracks / QRN.
The ferrite antenna was used in combination with the same preamp (M0BMU d= esign, 50 Ohm based), but without the attenuator.

The audible perfor= mance of the ferrite antenna seems to be even slightly better than with the loop. This is due to the smaller bandwidth (higher Q) of the ferrite anten= na that reduces the DCF and HGA levels even more. Markus was well audible o= n both antennas! The S/N was about 20...23 dB in 3 Hz noise bandwidth.
<= BR>A comparative spectrogram can be found at http:= //dl.dropbox.com/u/19882028/LF/DF6NM%20in%20CW%20in%20JN29OD96.png
F= irst one can see the ferrite antenna (slightly lower signal level but about= same S/N) recording, then the loop.
SpecLab was using a 10th order butt= erworth filter centered to 137 kHz, with 2 kHz bandwidth. The noiseblanker = was applied as well (9 dB treshold).
An audio file can be found here: http://dl.dropbox.com/u/19882028/LF/DF6NM%20in%20CW%= 20in%20JN29OD96.WAV
It uses a 500 Hz CW filter at 700 Hz AF. Except the filter and blanker, no further noise reduction is applied.
I person= ally find the first part of the file better to copy. This is the ferrite an= tenna!

Tnx Markus/DF6NM for the test.

73, Stefan/DK7FC
PS:
Copied further stations:
DG3MDE : http://dl.dropbox.com/u/198820= 28/LF/DG3MDE.jpg
DF6NM at 35 dB S/N in 488 mHz: http://dl.drop= box.com/u/19882028/LF/DF6NM_QRSS-3.jpg (wrong locator in the capture)



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