Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-df02.r1000.mx.aol.com (Internet Inbound) with ESMTP id 20997380000E7; Sun, 14 Aug 2011 17:47:27 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1QsiW7-0001sr-Un for rs_out_1@blacksheep.org; Sun, 14 Aug 2011 22:46:47 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QsiW7-0001si-EU for rsgb_lf_group@blacksheep.org; Sun, 14 Aug 2011 22:46:47 +0100 Received: from relay.uni-heidelberg.de ([129.206.100.212]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1QsiW6-0004Lo-Eb for rsgb_lf_group@blacksheep.org; Sun, 14 Aug 2011 22:46:47 +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 p7ELkj7i023083 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Sun, 14 Aug 2011 23:46:45 +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 p7ELkjxD009693 for ; Sun, 14 Aug 2011 23:46:45 +0200 Message-ID: <4E484183.9090805@iup.uni-heidelberg.de> Date: Sun, 14 Aug 2011 23:43:31 +0200 From: =?UTF-8?B?U3RlZmFuIFNjaMOkZmVy?= 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: <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> X-Spam-Score: 1.4 (+) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,RATWARE_GECKO_BUILD=1.426 Subject: Re: LF: Ferrite RX antennas Content-Type: multipart/alternative; boundary="------------020202060700090704020907" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.8 required=5.0 tests=HTML_30_40,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: 0:2:474892192:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d40d64e48426f5318 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. --------------020202060700090704020907 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by relay.uni-heidelberg.de id p7ELkj7i023083 Wolf, Which dimensions has your ferrite rod had? Never thought i will find a source for rods that are longer than 10 cm=20 but see:=20 http://www.box73.de/catalog/product_info.php?products_id=3D1422&osCsid=3D= rqlpfme957i65d7etjil1ntru5 even an official distributor.. Any better links? 73, Stefan/DK7FC Am 14.08.2011 22:27, schrieb wolf_dl4yhf: > Ferrite RX antennas.. been there when 136 kHz started. > Not as good as a larger air-core loop, possibly noise caused by the=20 > Barkhausen effect or similar effects, nonlinearities, etc. > Also beware the ferrite is a semiconductor so you will need some=20 > E-field screening, otherwise the ferrite material will couple noise=20 > into the windings. But it's not as bad as this may sound; actually I=20 > used a ferrite antenna for reception for some years until I discovered=20 > I had to disconnect the ...errr... RF counterpoise from the main=20 > antenna from the mains "ground", and only use an earthstake during=20 > receive, at DF0WD. > > On the other hand, it's compact, relatively light-weight, and (in a=20 > resonant configuration) gives a nice preselector. > I remember when I connected a ferrite antenna to a tiny receiver with=20 > SA612 "gilbert cell mixer", the first signal I heard was G3KEV calling=20 > cq in CW. Q5 in SSB bandwidth. > Such a receiver is extremely handy to go /p for reception, and compare=20 > different sites. > > 73, > Wolf DL4YHF. > > > Am 14.08.2011 21:43, schrieb Minto Witteveen: >> >> I haven=E2=80=99t thought about ferrite RX antenna for LF=E2=80=A6.My = guess is that=20 >> it is not going to work =E2=80=93 not without an external antenna coup= led to=20 >> the ferrite, and then what=E2=80=99s the point? >> DCF77 clocks often have trouble locking indoors or in the=20 >> neighborhood of =E2=80=98QRM=E2=80=99 generators like PC=E2=80=99s, an= d look what power DCF77=20 >> 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 >> *Sent:* Sunday, August 14, 2011 20:03 >> *To:* rsgb_lf_group@blacksheep.org >> *Subject:* Re: LF: Re: 137 grabbers >> >> BTW what do you think about a ferrite RX antenna for LF? Now i'm=20 >> opening an older discussion i expect ;-) >> >> 73, Stefan/DK7FC >> >> > --------------020202060700090704020907 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by relay.uni-heidelberg.de id p7ELkj7i023083 Wolf,

Which dimensions has your ferrite rod had?

Never thought i will find a source for rods that are longer than 10 cm but see: http://www.box73.de/catalog/product_info.php?products_id=3D1422&osC= sid=3Drqlpfme957i65d7etjil1ntru5

even an official distributor..

Any better links?

73, Stefan/DK7FC

Am 14.08.2011 22:27, schrieb wolf_dl4yhf:
Ferrite RX antennas.. been there when 136 kHz started.
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.=C2=A0 Q5 in SSB bandwidth.
Such a receiver is extremely handy to go /p for reception, and compare different sites.

73,
=C2=A0=C2=A0 Wolf DL4YHF.


Am 14.08.2011 21:43, schrieb Minto Witteveen:

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 a= ntenna 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 powe= r DCF77 is using=E2=80=A6
I could be entirely wrong of course=E2=80=A6

73=E2=80=99 Minto pa3bca

=C2=A0
Sent: Sunday, August 14, 2011 20:03
Subject: Re: LF: Re: 137 grabbers
=C2=A0
<snip>
BTW what do you think about a ferrite RX antenna for LF? Now i'm opening an older discussion i expect ;-)

73, Stefan/DK7FC



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