Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-ma04.r1000.mx.aol.com (Internet Inbound) with ESMTP id 536BB380000B2; Tue, 30 Aug 2011 08:07:29 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1QyN5B-0005BC-5X for rs_out_1@blacksheep.org; Tue, 30 Aug 2011 13:06:21 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QyN5A-0005B3-MF for rsgb_lf_group@blacksheep.org; Tue, 30 Aug 2011 13:06:20 +0100 Received: from relay.uni-heidelberg.de ([129.206.100.212]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1QyN59-0002ue-IU for rsgb_lf_group@blacksheep.org; Tue, 30 Aug 2011 13:06:20 +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 p7UC6DFL026441 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Tue, 30 Aug 2011 14:06:14 +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 p7UC6DYJ019699 for ; Tue, 30 Aug 2011 14:06:13 +0200 Message-ID: <4E5CD231.3010604@iup.uni-heidelberg.de> Date: Tue, 30 Aug 2011 14:06:09 +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: <16BC8B3CA8672445BC2A29B4C14A26D4379ED2AAB4@exlnmb01.eur.nsroot.net> <4DF9EFD1.5010208@iup.uni-heidelberg.de> <1313780109.51443.YahooMailNeo@web111907.mail.gq1.yahoo.com> <9CD1E11E8BC9402CB4AECECAC4088443@JimPC> <1314394178.5030.YahooMailNeo@web111905.mail.gq1.yahoo.com> <1314641183.5605.YahooMailNeo@web111910.mail.gq1.yahoo.com> <4E5CBC9A.5020900@iup.uni-heidelberg.de> <1314705226.37125.YahooMailNeo@web111901.mail.gq1.yahoo.com> In-Reply-To: <1314705226.37125.YahooMailNeo@web111901.mail.gq1.yahoo.com> X-Spam-Score: 1.4 (+) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,RATWARE_GECKO_BUILD=1.426 Subject: Re: LF: Re: Ferrite wideband antennas? Content-Type: multipart/alternative; boundary="------------040608080500040309000807" 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: 0:2:467222688:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d600c4e5cd281018c X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. --------------040608080500040309000807 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by relay.uni-heidelberg.de id p7UC6DFL026441 Hi Daniele, Fine! Yes, a nice field to play on. And if a sensitive /p antenna comes=20 out, this is ideal to coming LF with a nature trip ;-) 73, Stefan Am 30.08.2011 13:53, schrieb Daniele Tincani: > Hello Stefan, > Thanks a lot for your feedback. > Yesterday evening a purchased a bunch of 7 x MU400HH ferrites (10mm x=20 > 200mm each) on eBay, planning to join them together "in parallel" to=20 > form a fatter rod, no idea if it will be a good choice but let's play=20 > with this new toy ;-) Meanwhile I'm collecting ideas and hints from=20 > the web about construction (shielding, computing/measuring parameters,=20 > ect.). Projects are stacking as usual :-) > Best regards > Daniele > > *From:* Stefan Sch=E4fer > *To:* rsgb_lf_group@blacksheep.org > *Sent:* Tuesday, August 30, 2011 12:34 PM > *Subject:* Re: LF: Re: Ferrite wideband antennas? > > Hi Daniele, > >> Could it be possible to tune a ferrite loop over a frequency range as=20 >> wide as 100-500KHz? Or at least over the EU NDB band (say 300-500KHz)? >> Any practical suggestion (and/or references on the web) about how to=20 >> build it? > I think it is no problem. A narrow band but adjustable antenna is a=20 > good choice. Just use a large variable cap, e.g. 2x500 pF. It may be=20 > helpful to use switched caps and a smaller variable cap like i did. If=20 > you have a high Q antenna, you can then easily fine tune the system. > So maybe 5...100 pF +100 pF+180 pf+270 pF+560 pF or so, depending on=20 > your L. >> About the ferrites, there are several sellers on eBay who offer a=20 >> russian MU400HH type. Would it be suitable for LF? > Yes, very suitable. I have exactly these types in my LF ferrite=20 > antenna and got a Q of 480. Q will change over the frequency. So maybe=20 > it is even helpful to realise a switched L, for the higher frequencies. > > 73, Stefan > > --------------040608080500040309000807 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Hi Daniele,

Fine! Yes, a nice field to play on. And if a sensitive /p antenna comes out, this is ideal to coming LF with a nature trip ;-)

73, Stefan


Am 30.08.2011 13:53, schrieb Daniele Tincani:
 
Hello Stefan,
 
Thanks a lot for your feedback.
 
Yesterday evening a purchased a bunch of 7 x MU400HH ferrites (10mm x 200mm each) on eBay, planning to join them together "in parallel" to form a fatter rod, no idea if it will be a good choice but let's play with this new toy ;-) Meanwhile I'm collecting ideas and hints from the web about construction (shielding, computing/measuring parameters, ect.). Projects are stacking as usual :-)
 
Best regards
Daniele
 

From: Stefan Schäfer <Stefan.Schaefer@iup.uni-heidelberg.de>
To: rsgb_lf_group@blacksheep.org
Sent: Tuesday, August 30, 2011 12:34 PM
Subject: Re: LF: Re: Ferrite wideband antennas?

Hi Daniele,

Could it be possible to tune a ferrite loop over a frequency range as wide as 100-500KHz? Or at least over the EU NDB band (say 300-500KHz)?
Any practical suggestion (and/or references on the web) about how to build it?
I think it is no problem. A narrow band but adjustable antenna is a good choice. Just use a large variable cap, e.g. 2x500 pF. It may be helpful to use switched caps and a smaller variable cap like i did. If you have a high Q antenna, you can then easily fine tune the system.
So maybe 5...100 pF +100 pF+180 pf+270 pF+560 pF or so, depending on your L.
About the ferrites, there are several sellers on eBay who offer a russian MU400HH type. Would it be suitable for LF?
Yes, very suitable. I have exactly these types in my LF ferrite antenna and got a Q of 480. Q will change over the frequency. So maybe it is even helpful to realise a switched L, for the higher frequencies.

73, Stefan


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