Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mh05.r1000.mx.aol.com (Internet Inbound) with ESMTP id 4798238000206; Sun, 14 Aug 2011 17:34:36 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1QsiJR-0001hw-Nf for rs_out_1@blacksheep.org; Sun, 14 Aug 2011 22:33:41 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QsiJQ-0001hn-Vh for rsgb_lf_group@blacksheep.org; Sun, 14 Aug 2011 22:33:40 +0100 Received: from mail-ww0-f47.google.com ([74.125.82.47]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1QsiJO-000457-CP for rsgb_lf_group@blacksheep.org; Sun, 14 Aug 2011 22:33:40 +0100 Received: by wwf4 with SMTP id 4so3952267wwf.28 for ; Sun, 14 Aug 2011 14:33:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=message-id:from:to:references:in-reply-to:subject:date:mime-version :content-type:x-priority:x-msmail-priority:importance:x-mailer :x-mimeole; bh=zvdUCG0NQ7FkcLVT7CVcDxu1R/fzwI4yF2QFfg6UuBM=; b=Izm/mtvphpcqr1CAHt+F2d59v+OKl9O2JHg+ginrRsJsyb+I1R0hT2bBjhXPFdyesl bM1eXtgKBrVn0drIeoyK7+NzsnkCLYmxQLIILoUqDQSoeqDtny9HmlOtLFw4R+9B8Tdx buW/ydMnRT55uVXUPT2/nValLh4Oo2fx2UdPk= Received: by 10.227.2.72 with SMTP id 8mr2823522wbi.99.1313357612708; Sun, 14 Aug 2011 14:33:32 -0700 (PDT) Received: from PcMinto (h50208.upc-h.chello.nl [62.194.50.208]) by mx.google.com with ESMTPS id et16sm4058018wbb.53.2011.08.14.14.33.31 (version=SSLv3 cipher=OTHER); Sun, 14 Aug 2011 14:33:31 -0700 (PDT) Message-ID: <7F63C990AB12460D9E0A1FC11C87385D@PcMinto> From: Minto Witteveen To: References: <68BE37BD69E54DEE89CEBA8E30E9B94E@PcMinto> <4E47FFE9.10100@iup.uni-heidelberg.de> <3ED8E5422F1F45DBB8186E9D9870AD63@PcMinto> <4E480E02.9020706@iup.uni-heidelberg.de> <938BF599006244949F6CDDB5BA91F347@PcMinto> <4E482FBD.7030402@freenet.de> In-Reply-To: <4E482FBD.7030402@freenet.de> Date: Sun, 14 Aug 2011 23:33:24 +0200 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 15.4.3538.513 X-MimeOLE: Produced By Microsoft MimeOLE V15.4.3538.513 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: LF: Re: 137 grabbers Content-Type: multipart/alternative; boundary="----=_NextPart_000_03D5_01CC5ADA.8F5A9370" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.9 required=5.0 tests=HTML_30_40,HTML_MESSAGE, MISSING_OUTLOOK_NAME 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: 0:2:473576512:93952408 X-AOL-SCOLL-URL_COUNT: 0 X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-m278.1 ; domain : gmail.com DKIM : fail x-aol-sid: 3039ac1d60d94e483f6c603f X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. ------=_NextPart_000_03D5_01CC5ADA.8F5A9370 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hi Wolf, Stefan, LF Interesting=E2=80=A6 might be worth a try. It is easy to set up, I = already have the SA612 employed in my 137 KHz receiver.=20 So=E2=80=A6 just a ferrite bar, varco, buffered and amplified using a = J310, into my current lowpass filter?.. And then (if and when weather = permits, it has been raining here for more than two months) out into the = field with a fishing pole, miniwhip, ferrite bar, ft817,laptop, etc etc. = I was planning to do that anyway to see what the S/N is there, as a = comparison with my QTH. 73=E2=80=99s Minto pa3bca -------------------------------------------------------------------------= - Ceterum censeo Carthaginem delendam esse From: wolf_dl4yhf=20 Sent: Sunday, August 14, 2011 22:27 To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: Re: 137 grabbers Ferrite RX antennas.. been there when 136 kHz started.=20 Not as good as a larger air-core loop, possibly noise caused by the = Barkhausen effect or similar effects, nonlinearities, etc. Also beware the ferrite is a semiconductor so you will need some E-field = screening, otherwise the ferrite material will couple noise into the = windings. But it's not as bad as this may sound; actually I used a = ferrite antenna for reception for some years until I discovered I had to = disconnect the ...errr... RF counterpoise from the main antenna from the = mains "ground", and only use an earthstake during receive, at DF0WD. On the other hand, it's compact, relatively light-weight, and (in a = resonant configuration) gives a nice preselector. I remember when I connected a ferrite antenna to a tiny receiver with = SA612 "gilbert cell mixer", the first signal I heard was G3KEV calling = cq in CW. Q5 in SSB bandwidth.=20 Such a receiver is extremely handy to go /p for reception, and compare = different sites. 73, Wolf DL4YHF. Am 14.08.2011 21:43, schrieb Minto Witteveen:=20 I haven=E2=80=99t thought about ferrite RX antenna for LF=E2=80=A6.My = guess is that it is not going to work =E2=80=93 not without an external = antenna coupled to the ferrite, and then what=E2=80=99s the point? DCF77 clocks often have trouble locking indoors or in the neighborhood = of =E2=80=98QRM=E2=80=99 generators like PC=E2=80=99s, and look what = power DCF77 is using=E2=80=A6 I could be entirely wrong of course=E2=80=A6 73=E2=80=99 Minto pa3bca From: Stefan Sch=C3=A4fer=20 Sent: Sunday, August 14, 2011 20:03 To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: Re: 137 grabbers BTW what do you think about a ferrite RX antenna for LF? Now i'm = opening an older discussion i expect ;-) 73, Stefan/DK7FC ------=_NextPart_000_03D5_01CC5ADA.8F5A9370 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable

Hi Wolf, Stefan, LF

Interesting=E2=80=A6 might be worth a try. It is easy to = set up, I already=20 have the SA612 employed in my 137 KHz receiver.
So=E2=80=A6 just a = ferrite bar,=20 varco, buffered and amplified using a J310, into my current lowpass = filter?..=20  And then (if and when = weather=20 permits, it has been raining here for more than two months) out into the = field=20 with a fishing pole, miniwhip, ferrite bar, ft817,laptop, etc etc. I was = planning to do that anyway to see what the S/N is there, as a comparison = with my=20 QTH.

73=E2=80=99s Minto = pa3bca

 
-------------------------------------------------------------------= -------
Ceterum=20 censeo Carthaginem delendam esse
 
Sent: Sunday, August 14, 2011 22:27
Subject: Re: LF: Re: 137 grabbers
 
Ferrite=20 RX antennas.. been there when 136 kHz started.
Not as good as a = larger=20 air-core loop, possibly noise caused by the Barkhausen effect or similar = effects, nonlinearities, etc.
Also beware the ferrite is a = semiconductor so=20 you will need some E-field screening, otherwise the ferrite material = will couple=20 noise into the windings. But it's not as bad as this may sound; actually = I used=20 a ferrite antenna for reception for some years until I discovered I had = to=20 disconnect the ...errr... RF counterpoise from the main antenna from the = mains=20 "ground", and only use an earthstake during receive, at DF0WD.

On = the=20 other hand, it's compact, relatively light-weight, and (in a resonant=20 configuration) gives a nice preselector.
I remember when I connected = a=20 ferrite antenna to a tiny receiver with SA612 "gilbert cell mixer", the = first=20 signal I heard was G3KEV calling cq in CW.  Q5 in SSB bandwidth. =
Such a=20 receiver is extremely handy to go /p for reception, and compare = different=20 sites.

73,
   Wolf DL4YHF.


Am 14.08.2011 = 21:43,=20 schrieb Minto Witteveen:=20

I haven=E2=80=99t thought about ferrite RX antenna for = LF=E2=80=A6.My guess is=20 that it is not going to work =E2=80=93 not without an external antenna = coupled to the=20 ferrite, and then what=E2=80=99s the point?
DCF77 clocks often have = trouble locking=20 indoors or in the neighborhood of =E2=80=98QRM=E2=80=99 generators = like PC=E2=80=99s, and look what=20 power DCF77 is using=E2=80=A6
I could be entirely wrong of=20 course=E2=80=A6

73=E2=80=99 Minto = pa3bca

 
From: Stefan Sch=C3=A4fer
Sent: Sunday, August 14, 2011 20:03
Subject: Re: LF: Re: 137 grabbers
 
<snip>
BTW what do you think about a = ferrite RX=20 antenna for LF? Now i'm opening an older discussion i expect = ;-)

73,=20 Stefan/DK7FC



<= /DIV> ------=_NextPart_000_03D5_01CC5ADA.8F5A9370--