Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mp04.r1000.mx.aol.com (Internet Inbound) with ESMTP id D15CB38000096; Tue, 16 Aug 2011 18:33:47 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1QtSBN-0006UM-45 for rs_out_1@blacksheep.org; Tue, 16 Aug 2011 23:32:25 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QtSBM-0006UD-Hf for rsgb_lf_group@blacksheep.org; Tue, 16 Aug 2011 23:32:24 +0100 Received: from relay.uni-heidelberg.de ([129.206.100.212]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1QtSBL-0007GJ-78 for rsgb_lf_group@blacksheep.org; Tue, 16 Aug 2011 23:32:24 +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 p7GMWMP3026178 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Wed, 17 Aug 2011 00:32:22 +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 p7GMWLpa000506 for ; Wed, 17 Aug 2011 00:32:22 +0200 Message-ID: <4E4AEF31.5010306@iup.uni-heidelberg.de> Date: Wed, 17 Aug 2011 00:29:05 +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> <4E496FF9.4040608@iup.uni-heidelberg.de> <0A4ED65EC3B244A3BD0DAD6ACFF43793@JimPC> <4E4A5597.4070709@iup.uni-heidelberg.de> <3746D901368F4C139E414F9110153EEE@JimPC> <4E4A9A1F.2060600@iup.uni-heidelberg.de> <1B55B625C3CD4D529EC361D9C5D79D96@JimPC> <4E4AD4C8.8000509@iup.uni-heidelberg.de> In-Reply-To: <4E4AD4C8.8000509@iup.uni-heidelberg.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="------------050206050403070401020109" 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: 1:2:482352256:93952408 X-AOL-SCOLL-URL_COUNT: 1 x-aol-sid: 3039ac1dc1484e4af04b4875 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. --------------050206050403070401020109 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 p7GMWMP3026178 Jim, LF, Wow, it works very well! I took that Litz wire that is a 30x0.1mm wire in my case and wound 55=20 turns on a double side bonding tape across the PVC tube. First the Q was low, about 130. I noted that sourrounding metallic parts=20 have an influence on the Q. Then i placed the rod on a cardboard box. Q=20 was 160 at 136.5 kHz (took 2.44 nF) but i noted it decreased=20 continuously. I thought about a thermal drift of the caps that just have=20 been soldered before. Then i took a 2.2 nF styroflex cap and achieved a Q of=20 486!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Unbelivable :-)) For the spectrum and peak, see: http://dl.dropbox.com/u/19882028/LF/Q.jpg This is the arrangement (i took a 47 pF cap to inject a white noise from=20 a NI PXI-6115 ):=20 http://dl.dropbox.com/u/19882028/LF/arrangement.JPG Almost a bit to sharp, isn't it?! What do you (and others) think? 73, Stefan/DK7FC Am 16.08.2011 22:36, schrieb Stefan Sch=C3=A4fer: > Jim, LF, > > I'll try to go on as fast as the distributor and ebay did ;-) So this=20 > is the current situation: > > Decided to use the 2x7 bundle. The cross section area of 7 pcs. just=20 > lokks better :-) Also the complete stick is much more handy and robust. > > Markus/DF6NM gave me the hint to overlap the inner rod by 50%. So i=20 > intentionally broke one rod and put the 2 halfs to the inner ends. One=20 > complete one is now in the inner center. > > See: http://dl.dropbox.com/u/19882028/LF/ferrite%20antenna%20parts.JPG > > I took a simple bonding tape to isolate the rods from each other. The=20 > whole arrangement was fixed by bonding tape and put into a stable and=20 > very proper PVC tube with 2.5 mm thickness, making the rod very robust=20 > and give some distance between winding and ferrite (just as in the=20 > magic antenna article ;-) ). > > Ther was even some place to add a bit of that transport foil with the=20 > air bubbles inside, you know ;-) Perhaps this will be some kind of=20 > shock protection (hopefully never needed) and fixed the rods inside=20 > the tube. > > http://dl.dropbox.com/u/19882028/LF/inside.JPG > > Now the outer dimensiona are 285 mm x 33 mm. > > As a first test i wound a simple wire arround the rod, 22 turns.=20 > Resonance C is 11.2 nF and f res =3D 137,1 kHz. Q =3D 100 (unloaded).=20 > During the measurement i was irritated by a strange peak near 137.7=20 > kHz which was my own transmission during that time ;-) > So L must be 120 uH. Not so much... > > Will go on now using the Litz wire and start with about 40 turns and=20 > see what comes out. Then i go for 60 turns, maybe 80 if Q is still=20 > rising. > > 73, Stefan/DK7FC > > > Am 16.08.2011 19:01, schrieb James Moritz: >> Dear Stefan, LF Group, >> >> >> ----- Original Message ----- >>> The 20 mV is the peak level (thus mVp ;-) ) while the mentioned 100=20 >>> uV is rms. >> >> OK - so that makes your RX noise level 3dB lower, and gives you 3dB=20 >> more margin, which is good! >> >> Cheers, Jim Moritz >> 73 de M0BMU --------------050206050403070401020109 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 p7GMWMP3026178 Jim, LF,

Wow, it works very well!
I took that Litz wire that is a 30x0.1mm wire in my case and wound 55 turns on a double side bonding tape across the PVC tube.

First the Q was low, about 130. I noted that sourrounding metallic parts have an influence on the Q. Then i placed the rod on a cardboard box. Q was 160 at 136.5 kHz (took 2.44 nF) but i noted it decreased continuously. I thought about a thermal drift of the caps that just have been soldered before.

Then i took a 2.2 nF styroflex cap and achieved a Q of 486!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! Unbelivable :-))
For the spectrum and peak, see: http://dl.dropbox.com/u/19882028/LF/Q.jpg

This is the arrangement (i took a 47 pF cap to inject a white noise from a N= I PXI-6115): http://dl.dropbox.com/u/19882028/LF= /arrangement.JPG

Almost a bit to sharp, isn't it?!

What do you (and others) think?

73, Stefan/DK7FC


Am 16.08.2011 22:36, schrieb Stefan Sch=C3=A4fer:
Jim, LF,

I'll try to go on as fast as the distributor and ebay did ;-) So this is the current situation:

Decided to use the 2x7 bundle. The cross section area of 7 pcs. just lokks better :-) Also the complete stick is much more handy and robust.

Markus/DF6NM gave me the hint to overlap the inner rod by 50%. So i intentionally broke one rod and put the 2 halfs to the inner ends. One complete one is now in the inner center.

See: http://dl.dropbox.com/u/1988202= 8/LF/ferrite%20antenna%20parts.JPG

I took a simple bonding tape to isolate the rods from each other. The whole arrangement was fixed by bonding tape and put into a stable and very proper PVC tube with 2.5 mm thickness, making the rod very robust and give some distance between winding and ferrite (just as in the magic antenna article ;-) ).

Ther was even some place to add a bit of that transport foil with the air bubbles inside, you know ;-) Perhaps this will be some kind of shock protection (hopefully never needed) and fixed the rods inside the tube.

http://dl.dropbox.com/u/19882028/LF/inside.JPG

Now the outer dimensiona are 285 mm x 33 mm.

As a first test i wound a simple wire arround the rod, 22 turns. Resonance C is 11.2 nF and f res =3D 137,1 kHz. Q =3D 100 (unloaded). During the measurement i was irritated by a strange peak near 137.7 kHz which was my own transmission during that time ;-)
So L must be 120 uH. Not so much...

Will go on now using the Litz wire and start with about 40 turns and see what comes out. Then i go for 60 turns, maybe 80 if Q is still rising.

73, Stefan/DK7FC


Am 16.08.2011 19:01, schrieb James Moritz:
Dear Stefan, LF Group,


----- Original Message -----
The 20 mV is the peak level (thus mVp ;-) ) while the mentioned 100 uV is rms.

OK - so that makes your RX noise level 3dB lower, and gives you 3dB more margin, which is good!

Cheers, Jim Moritz
73 de M0BMU
--------------050206050403070401020109--