Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dg05.r1000.mx.aol.com (Internet Inbound) with ESMTP id 8DAD338000090; Sun, 14 Aug 2011 15:37:16 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1QsgTl-000118-UG for rs_out_1@blacksheep.org; Sun, 14 Aug 2011 20:36:13 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QsgTl-00010z-5h for rsgb_lf_group@blacksheep.org; Sun, 14 Aug 2011 20:36:13 +0100 Received: from mail-wy0-f171.google.com ([74.125.82.171]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1QsgTi-0002AF-SJ for rsgb_lf_group@blacksheep.org; Sun, 14 Aug 2011 20:36:13 +0100 Received: by wyh13 with SMTP id 13so4876990wyh.16 for ; Sun, 14 Aug 2011 12:36:04 -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=WVpPW/zNBa5wmJdCmWFtIboJ2PKBCU7DoyU+l057YFw=; b=LVJ9P7Uk3bXGIM4SuPSaysRMJ87V+xehnP4wrH9LE66IsVQbYYRbrWL8uheHIMTEic QCTGrKPRsoCZae7wjyPEpV+ERp9jsPUvkvRFoypB/6kr4DfAZUWS1w9WazbwefGJX5fm KbuJsOI9p4sRXBdDkFxwd5IieAbl3Pg5D9URs= Received: by 10.216.175.130 with SMTP id z2mr2199126wel.63.1313350563495; Sun, 14 Aug 2011 12:36:03 -0700 (PDT) Received: from PcMinto (h50208.upc-h.chello.nl [62.194.50.208]) by mx.google.com with ESMTPS id p49sm3190751weq.31.2011.08.14.12.36.01 (version=SSLv3 cipher=OTHER); Sun, 14 Aug 2011 12:36:02 -0700 (PDT) Message-ID: <9AA0B2C99BF04CFF93961063D270EEEE@PcMinto> From: Minto Witteveen To: References: <68BE37BD69E54DEE89CEBA8E30E9B94E@PcMinto> <4E47FFE9.10100@iup.uni-heidelberg.de> <3ED8E5422F1F45DBB8186E9D9870AD63@PcMinto> <4E480E02.9020706@iup.uni-heidelberg.de> In-Reply-To: <4E480E02.9020706@iup.uni-heidelberg.de> Date: Sun, 14 Aug 2011 21:35:55 +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_036C_01CC5ACA.25D68090" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.7 required=5.0 tests=HTML_20_30,HTML_FONTCOLOR_BLUE, 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: 0:2:431492736:93952408 X-AOL-SCOLL-URL_COUNT: 0 X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-m025.1 ; domain : gmail.com DKIM : fail x-aol-sid: 3039ac1d410d4e4823ec19bf 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_036C_01CC5ACA.25D68090 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Stefan, LF I use the 4C6 cores in my Lowpass filter for 137. I tried the FT50-43, = and the 4C6. The latter needed about 44 windings for 80 uH so = it=E2=80=99s AL is 41 nH/T^2. (varies a bit per core). The AL of an = FT50-43 is about 10 times as high. 100 uH is perfectly doable with a 4C6 = core of 14 mm dia.=20 The Q of the FT types was around 50, the 4C6 was 140 @ 137 KHz @ 80 uH. 4C6 (originally made by Philips) is a well-known core type here in PA. = The larger types are often used for HF baluns. I understand that Philips = no longer makes them so they are getting harder to come by. I bought a bunch of 14mm 4C6 cores at = http://www.vandijkenelektronica.nl/ for =E2=82=AC 0,50 apiece.=20 Pot cores are more expensive but they have the advantage of being = adjustable, which is nice if you want to construct (small) = bandfilters=E2=80=A6 73=E2=80=99s Minto pa3bca -------------------------------------------------------------------------= - Ceterum censeo Carthaginem delendam esse 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 Minto, Daniele,=20 @Daniele: Nice to read you also want to join in on LF! BTW VLF is not = forgotten here, i want to come back in September. But want to have the = LF system ready for the DX season and wat for lower QRN on the Dreamers = Band... You don't have a licence and cannot TX? Wouldn't it be worth to learn = for a licence for that reason? :-) And have you done further tests on sferics and so on your remote VLF = QTH? Any news? Just got re-fascinated by John/F5VLF about the earth antenna stuff and = want to do more experiments on that antenna again but LF improvements = are very time consuming! But i have holidays now :-))) I am curious how = the earth antenna performs as a RX antenna on 137 kHz (directional = pattern and gain and noise). As a TX antenna i will be to lossy i think = and its not worth the effort carrying 100s of kg of batteries on the = hill for doing some CQ calls that are not answered.... @Minto: Am 14.08.2011 19:33, schrieb Minto Witteveen:=20 Above 10 MHz the gain drops off rapidly, it is nearly useless at 14 = MHz. a -77 type would be much worse there I think. Sure. I just talked about LF now. I read the -43 type is suitable for = 40...400 MHz, at least this is said in the catalog... As for the Q: I did a comparison between an FT50-43 and a 14 mm 4C6 = (for my 137 KHz low-pass filter, see my website). The Q of the FT50-43 = coil was abt 50, the 4C6 =E2=80=93 with a lower Al - was 140 !! Interesting! 140 at which L? I am searching for ferrite cores to achieve = a high Q on LF, in the range of 100...1000uH. Where can i get these = cores? At RS? Where do you buy them? They are usually samller, cheaper = and easier to handle than pot cores. 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_036C_01CC5ACA.25D68090 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable

Stefan, LF

I use=20 the 4C6 cores in my Lowpass filter for 137. I tried the FT50-43, and the = 4C6.=20 The latter needed about 44 windings for 80 uH so it=E2=80=99s AL is 41 = nH/T^2. (varies a=20 bit per core). The AL of an FT50-43 is about 10 times as high. 100 uH is = perfectly doable with a 4C6 core of 14 mm dia.
The Q of the FT types = was=20 around 50, the 4C6 was 140 @ 137 KHz @ 80 uH.
4C6 (originally made by = Philips) is a well-known core type here in PA. The larger types are = often used=20 for HF baluns. I understand that Philips no longer makes them so they = are=20 getting harder to come by.
I bought a bunch of 14mm 4C6 cores at = http://www.vandijkenelektronica.nl/ for =E2=82=AC 0,50 apiece.
Pot cores = are more expensive=20 but they have the advantage of being adjustable, which is nice if you = want to=20 construct (small) bandfilters=E2=80=A6

73=E2=80=99s Minto pa3bca

 
-------------------------------------------------------------------= -------
Ceterum=20 censeo Carthaginem delendam esse
 
From: Stefan = Sch=C3=A4fer
Sent: Sunday, August 14, 2011 20:03
Subject: Re: LF: Re: 137 grabbers
 
Minto,=20 Daniele,

@Daniele: Nice to read you also want to join in on LF! = BTW VLF=20 is not forgotten here, i want to come back in September. But want to = have the LF=20 system ready for the DX season and wat for lower QRN on the Dreamers=20 Band...
You don't have a licence and cannot TX? Wouldn't it be worth = to learn=20 for a licence for that reason? :-)
And have you done further tests on = sferics=20 and so on your remote VLF QTH? Any news?
Just got re-fascinated by = John/F5VLF=20 about the earth antenna stuff and want to do more experiments on that = antenna=20 again but LF improvements are very time consuming! But i have holidays = now :-)))=20 I am curious how the earth antenna performs as a RX antenna on 137 kHz=20 (directional pattern and gain and noise). As a TX antenna i will be to = lossy i=20 think and its not worth the effort carrying 100s of kg of batteries on = the hill=20 for doing some CQ calls that are not answered....

@Minto:
Am=20 14.08.2011 19:33, schrieb Minto Witteveen:=20

Above 10 MHz the gain drops off rapidly, it is nearly = useless at=20 14 MHz. a -77 type would be much worse there I=20 think.

Sure. I = just talked=20 about LF now. I read the -43 type is suitable for 40...400 MHz, at least = this is=20 said in the catalog...

As for the Q: I did a comparison between an FT50-43 and = a 14 mm=20 4C6 (for my 137 KHz low-pass filter, see my website). The Q of the = FT50-43=20 coil was abt 50, the 4C6 =E2=80=93 with a lower Al - was 140=20 !!

Interesting! 140 at = which L?=20 I am searching for ferrite cores to achieve a high Q on LF, in the range = of=20 100...1000uH. Where can i get these cores? At RS? Where do you buy them? = They=20 are usually samller, cheaper and easier to handle than pot = cores.

BTW=20 what do you think about a ferrite RX antenna for LF? Now i'm opening an = older=20 discussion i expect ;-)

73, Stefan/DK7FC


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