Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dg04.r1000.mx.aol.com (Internet Inbound) with ESMTP id 21549380000E5; Mon, 15 Aug 2011 15:17:59 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Qt2f1-0007Oz-T9 for rs_out_1@blacksheep.org; Mon, 15 Aug 2011 20:17:19 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Qt2f1-0007Oq-9y for rsgb_lf_group@blacksheep.org; Mon, 15 Aug 2011 20:17:19 +0100 Received: from relay.uni-heidelberg.de ([129.206.100.212]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1Qt2ez-0001aA-PC for rsgb_lf_group@blacksheep.org; Mon, 15 Aug 2011 20:17:19 +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 p7FJHGIZ019472 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Mon, 15 Aug 2011 21:17:17 +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 p7FJHGoO024483 for ; Mon, 15 Aug 2011 21:17:16 +0200 Message-ID: <4E496FF9.4040608@iup.uni-heidelberg.de> Date: Mon, 15 Aug 2011 21:14:01 +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> <4E484183.9090805@iup.uni-heidelberg.de> <4E494A57.90105@freenet.de> <4E4956DA.1060201@iup.uni-heidelberg.de> <4E49643E.5090708@freenet.de> In-Reply-To: <4E49643E.5090708@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="------------060409060604090308060107" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=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: 0:2:434706624:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d410c4e4970e705c4 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. --------------060409060604090308060107 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 p7FJHGIZ019472 Hi Wolf, I thought about a resonated design which has a separate output winding=20 at 50 Ohm, fed to some meters of RG174 (to be far enough from the=20 netbook) and then to a preamp which i already have available (the M0BMU=20 design for the single turn loop). Then feed this to my homemade RX which=20 is way better than the 706 (in a comparison during the QSO with HB9ASB=20 there was nothing detectable on the 706+preamp while Anton was perfectly=20 audible on the homemade design (without the external preamp:=20 http://dl.dropbox.com/u/19882028/LF/HB9ASB.WAV)... Am 15.08.2011 20:23, schrieb wolf_dl4yhf: > Hi Stefan, > > For a resonant design (tuned with parallel capacitor) I'd use the litz=20 > wire. For the broadband design (terminated with a low-Z amplifier) it=20 > shouldn't matter too much, but 0.5 mm wire diameter would be the=20 > minimum. The thinner the wire, the larger the 'R', R is noisy, and we=20 > don't want noise ;-) > > 7 rods in a bundle, and two of these bundles sound good. But it=20 > depends on the material (permeability) if it makes sense to use 8=20 > "parallel" rods - consider this: one single rod may already 'attract'=20 > enough magnetic field lines from the far field; 7 rods will not=20 > attract 7 times as much ! Anyway for backpack operation you don't have=20 > the choice to build a meter-long rod like Lubos' large antenna. Yes, but 3 rods in series (=3D 0.42 m) would be fine as well. So i could= =20 use 3x5 rods instead, or 3x3 if this would be sufficient. > > Beware that my crossed-loop antenna was built for VLF, not LF. I know. Thus using no litz wire is not so critical... It was in 2003. Haven't known that your VLF observations started so=20 early ;-) 73, Stefan > > Cheers, > Wolf . > > > Am 15.08.2011 19:26, schrieb Stefan Sch=C3=A4fer: >> Hello Wolf, >> >> Thanks to the link to your nice to read article. I just found it a=20 >> hour before your mail and already read it ;-) >> >> Well, i also prefer the usual configuration instead of that sleeve=20 >> antenna. Also i have to keep the focus on my actual goal: Making a=20 >> handy antenna for amateur LF / p operation without a car! And the 16=20 >> rods i will get (14 cm long, 8mm diameter) will be best in a 2x7=20 >> config. i think. Or do you rather suggest 3x5 or even 4x4? >> 2x7 is then about 30 cm long which is very fine for a backpack and=20 >> should be robust enough. >> I would use the same double side bonding tape, this is very useful to=20 >> get a first fixed arrangement. Then putting all that in a PVC tube,=20 >> 2mm thickness and add the turns above the tube. >> Would you recommend litz wire or standard 0.5 mm enamelled wire? >> As an E field shield i would use aluminium bonding tape, without=20 >> making a shutcut turn of course. >> >> So the newcomers should not think that this antenna is the best what=20 >> one can use for LF. Just in that special case of /p i see advantages.=20 >> Otherwise a well designed loop (+ preamp or a very sensitive RX, if a=20 >> samll loop is used) or E field antenna such as the PA0RDT should be=20 >> preferred, as Alan already pointed out. >> >> Looking forward to a direct comparison of the DCF39 SNR that can be=20 >> achieved and to the first amateur signal received with that antenna=20 >> in /p... >> >> 73, Stefan/DK7FC >> > --------------060409060604090308060107 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 p7FJHGIZ019472 Hi Wolf,

I thought about a resonated design which has a separate output winding at 50 Ohm, fed to some meters of RG174 (to be far enough from the netbook) and then to a preamp which i already have available (the M0BMU design for the single turn loop). Then feed this to my homemade RX which is way better than the 706 (in a comparison during the QSO with HB9ASB there was nothing detectable on the 706+preamp while Anton was perfectly audible on the homemade design (without the external preamp: http://dl.dropbox.com/u/19882028/LF/HB9ASB.WAV)...<= br>

Am 15.08.2011 20:23, schrieb wolf_dl4yhf:
Hi Stefan,

For a resonant design (tuned with parallel capacitor) I'd use the litz wire. For the broadband design (terminated with a low-Z amplifier) it shouldn't matter too much, but 0.5 mm wire diameter would be the minimum. The thinner the wire, the larger the 'R', R is noisy, and we don't want noise ;-)

7 rods in a bundle, and two of these bundles sound good. But it depends on the material (permeability) if it makes sense to use 8 "parallel" rods - consider this: one single rod may already 'attract' enough magnetic field lines from the far field; 7 rods will not attract 7 times as much ! Anyway for backpack operation you don't have the choice to build a meter-long rod like Lubos' large antenna.
Yes, but 3 rods in series (=3D=C2=A0 0.42 m) would be fine as well. So i = could use 3x5 rods instead, or 3x3 if this would be sufficient.

Beware that my crossed-loop antenna was built for VLF, not LF.
I know. Thus using no litz wire is not so critical...
It was in 2003. Haven't known that your VLF observations started so early ;-)


73, Stefan

Cheers,
=C2=A0=C2=A0=C2=A0 Wolf .


Am 15.08.2011 19:26, schrieb Stefan Sch=C3=A4fer:
Hello Wolf,

Thanks to the link to your nice to read article. I just found it a hour before your mail and already read it ;-)

Well, i also prefer the usual configuration instead of that sleeve antenna. Also i have to keep the focus on my actual goal: Making a handy antenna for amateur LF / p operation without a car! And the 16 rods i will get (14 cm long, 8mm diameter) will be best in a 2x7 config. i think. Or do you rather suggest 3x5 or even 4x4?
2x7 is then about 30 cm long which is very fine for a backpack and should be robust enough.
I would use the same double side bonding tape, this is very useful to get a first fixed arrangement. Then putting all that in a PVC tube, 2mm thickness and add the turns above the tube.
Would you recommend litz wire or standard 0.5 mm enamelled wire?
As an E field shield i would use aluminium bonding tape, without making a shutcut turn of course.

So the newcomers should not think that this antenna is the best what one can use for LF. Just in that special case of /p i see advantages. Otherwise a well designed loop (+ preamp or a very sensitive RX, if a samll loop is used) or E field antenna such as the PA0RDT should be preferred, as Alan already pointed out.

Looking forward to a direct comparison of the DCF39 SNR that can be achieved and to the first amateur signal received with that antenna in /p...

73, Stefan/DK7FC


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