Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mp05.r1000.mx.aol.com (Internet Inbound) with ESMTP id 0E9BE38000087; Sun, 14 Aug 2011 13:34:58 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1QseZe-0000AM-2O for rs_out_1@blacksheep.org; Sun, 14 Aug 2011 18:34:10 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QseZd-0000AD-B9 for rsgb_lf_group@blacksheep.org; Sun, 14 Aug 2011 18:34:09 +0100 Received: from mail-ww0-f47.google.com ([74.125.82.47]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1QseZb-0008TD-2l for rsgb_lf_group@blacksheep.org; Sun, 14 Aug 2011 18:34:09 +0100 Received: by wwf4 with SMTP id 4so3872014wwf.28 for ; Sun, 14 Aug 2011 10:34:01 -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=OW0C2wNSGkhofsLl+WYmwa/kCCMhmeFbJ+lGH8aw4eE=; b=GUDp1fZ0l9lSMkVfNS3ebCDg5tqVQ03k74HtVK7M4BY/6rYYlHdSiqc1FWPabKRahV 6VKKjcDKb71Vu/v34Kr97ZfjWv7QjFu9Z8o/rYT6XEUKNmqkMNvHn0xv2QHJ+7Ljn7ZM IeI5/gNvqRKPhBGKYP8Y9DCrKPX6CmvMGg9fs= Received: by 10.227.167.75 with SMTP id p11mr2844208wby.4.1313343240258; Sun, 14 Aug 2011 10:34:00 -0700 (PDT) Received: from PcMinto (h50208.upc-h.chello.nl [62.194.50.208]) by mx.google.com with ESMTPS id 8sm3929321wbx.0.2011.08.14.10.33.58 (version=SSLv3 cipher=OTHER); Sun, 14 Aug 2011 10:33:59 -0700 (PDT) Message-ID: <3ED8E5422F1F45DBB8186E9D9870AD63@PcMinto> From: Minto Witteveen To: References: <68BE37BD69E54DEE89CEBA8E30E9B94E@PcMinto> <4E47FFE9.10100@iup.uni-heidelberg.de> In-Reply-To: <4E47FFE9.10100@iup.uni-heidelberg.de> Date: Sun, 14 Aug 2011 19:33:52 +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_0340_01CC5AB9.192163D0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: ** X-Spam-Status: No, hits=2.9 required=5.0 tests=HTML_30_40,HTML_MESSAGE, MISSING_OUTLOOK_NAME,WEIRD_PORT 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: 0:2:431084032:93952408 X-AOL-SCOLL-URL_COUNT: 0 X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-d307.2 ; domain : gmail.com DKIM : fail x-aol-sid: 3039ac1dc1494e48074227da 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_0340_01CC5AB9.192163D0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Stefan, LF Not my own design, I don=E2=80=99t remember exactly where I got it but I = am pretty sure I stole the idea =E2=80=98from the Internet=E2=80=99 and = possible made some changes. The bc337 was used as I have a lot of them = lying around, and they are much better than for instance the bc547 (my = other jellybean transistor). The reason I used a -43 type toroid is because I built it for use on 500 = KHz and up. Especially for 80 and 40 meters. Type-43 is better here = than Type-77. On HF this loop is _much, much_ better than my end-fed TX = wire in terms of S/N. The wire picks up a lot of noise from the house = (and from my neighbors houses). The loop is placed to null- out this QRM = as much as possible. 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. 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 !! Needed more = turns ofcourse. On the other hand the Q of this toroid is not very = important here as it is used as a broad-band transformer. This is only my hobby=E2=80=A6 Originally I am a Civil Engineer (but my = job now is in IT). 73=E2=80=99s Minto pa3bca -------------------------------------------------------------------------= - Ceterum censeo Carthaginem delendam esse From: Stefan Sch=C3=A4fer=20 Sent: Sunday, August 14, 2011 19:03 To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: Re: 137 grabbers This looks like a very good design. Fascinating easy!! Is it completely = grown in your head or have you seen it somewhere in the web? What is the gain, about? I know the BC337 as a low noise NPN transistor. Your loop is 2m diameter? How many dBs is the background noise abovethe = soundcard noise? Another question: Why are the T37-43 (the 43 types in general) preferred = to the 77 types? The 77 types have a higher AL value and should come out = with less turns. I tried to wind a band pass coil with but of the types = (T50-43 and T50-77) and achieved about the same Q. Is it just a question = of an available distributor? And what is your job? Do you have to design electrical circuits? ;-) 73, Stefan/DK7FC Am 14.08.2011 18:07, schrieb Minto Witteveen:=20 Loop antenna: = http://www.pa3bca.nl/index.php?option=3Dcom_content&view=3Darticle&id=3D1= 0&Itemid=3D14 From: Minto Witteveen=20 Sent: Sunday, August 14, 2011 18:03 To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: 137 grabbers Mal, LF, I am now using a single-turn loop in the backyard (hight abt 2 meters) = instead of the miniwhip.=20 One of these days I will test again with the miniwhip. First = impression (testing the noise against DCF39) was that they dont differ = very much. 73=E2=80=99s Minto pa3bca (grabber at http://pa3bca.pa3bca.nl:8181)=20 = -------------------------------------------------------------------------= - Ceterum censeo Carthaginem delendam esse From: mal hamilton=20 Sent: Sunday, August 14, 2011 17:51 To: rsgb=20 Subject: LF: 137 grabbers LF My signal seems consistant on the PA3PCA grabber but varies a lot on = the DK7FC grabber, sometimes stronger on this grabber and others like = now barely visible. Could it be the type of antenna in use ie one is = more prone to noise es qsb than the other? de mal/g3kev ------=_NextPart_000_0340_01CC5AB9.192163D0 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable

Stefan, LF

Not my own design, I don=E2=80=99t remember exactly where = I got it but I am=20 pretty sure I stole the idea =E2=80=98from the Internet=E2=80=99 and = possible made some changes.=20 The bc337 was used as I have a lot of them lying around, and they are = much=20 better than for instance the bc547 (my other jellybean = transistor).
The=20 reason I used a -43 type toroid is because I built it for use on 500 KHz = and up.=20  Especially for 80 and 40 = meters.=20 Type-43 is better here than Type-77. On HF this loop is _much, much_ = better than=20 my end-fed TX wire in terms of S/N. The wire picks up a lot of noise = from the=20 house (and from my neighbors houses). The loop is placed to null- out = this QRM=20 as much as possible.
Above 10 MHz the gain drops off rapidly, it is = nearly=20 useless at 14 MHz. a -77 type would be much worse there I think.
As = for the=20 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=20 =E2=80=93 with a lower Al - was 140 !! Needed more turns ofcourse. On = the other hand the=20 Q of this toroid is not very important here as it is used as a = broad-band=20 transformer.

This is only my hobby=E2=80=A6 Originally I am a Civil = Engineer (but my job=20 now is in IT).

73=E2=80=99s Minto = pa3bca

 
-------------------------------------------------------------------= -------
Ceterum=20 censeo Carthaginem delendam esse
 
From: Stefan = Sch=C3=A4fer
Sent: Sunday, August 14, 2011 19:03
Subject: Re: LF: Re: 137 grabbers
 
This=20 looks like a very good design. Fascinating easy!! Is it completely grown = in your=20 head or have you seen it somewhere in the web?
What is the gain, = about? I=20 know the BC337 as a low noise NPN transistor.
Your loop is 2m = diameter? How=20 many dBs is the background noise abovethe soundcard = noise?

Another=20 question: Why are the T37-43 (the 43 types in general) preferred to the = 77=20 types? The 77 types have a higher AL value and should come out with less = turns.=20 I tried to wind a band pass coil with but of the types (T50-43 and = T50-77) and=20 achieved about the same Q. Is it just a question of an available=20 distributor?

And what is your job? Do you have to design = electrical=20 circuits? ;-)

73, Stefan/DK7FC




Am 14.08.2011 = 18:07,=20 schrieb Minto Witteveen:=20
Loop antenna: http://www.pa3bca.nl/index.php?option=3Dcom_cont= ent&view=3Darticle&id=3D10&Itemid=3D14
Sent: Sunday, August 14, 2011 18:03
Subject: Re: LF: 137 grabbers
 
Mal, LF,
 
I am now using a single-turn loop in the backyard (hight abt 2 = meters)=20 instead of the miniwhip.
One of these days I will test again with = the=20 miniwhip. First impression (testing the noise against DCF39) was that = they=20 dont differ very much.
 
73=E2=80=99s Minto pa3bca (grabber at http://pa3bca.pa3bca.nl:8181)
 
-------------------------------------------------------------------= -------
Ceterum=20 censeo Carthaginem delendam esse
 
From: mal = hamilton=20
Sent: Sunday, August 14, 2011 17:51
To: rsgb=20
Subject: LF: 137 grabbers
 
LF
My signal seems consistant on the PA3PCA = grabber but=20 varies a lot on the DK7FC grabber, sometimes stronger on this grabber = and=20 others like now barely visible. Could it be the type of antenna in use = ie one=20 is more prone to noise es qsb than the other?
de
mal/g3kev
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