Return-Path: Received: from rly-df12.mx.aol.com (rly-df12.mail.aol.com [172.19.156.25]) by air-df08.mail.aol.com (v123.4) with ESMTP id MAILINDF082-59249d468f0e1; Thu, 02 Apr 2009 03:28:03 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-df12.mx.aol.com (v123.4) with ESMTP id MAILRELAYINDF121-59249d468f0e1; Thu, 02 Apr 2009 03:27:47 -0400 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1LpHKS-00009N-7N for rs_out_1@blacksheep.org; Thu, 02 Apr 2009 08:27:12 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1LpHKR-00009E-Qd for rsgb_lf_group@blacksheep.org; Thu, 02 Apr 2009 08:27:11 +0100 Received: from mail.cz.gmc.net ([77.48.211.230]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1LpHKO-0004qp-Qb for rsgb_lf_group@blacksheep.org; Thu, 02 Apr 2009 08:27:11 +0100 Received: from Lenovo (192.168.100.32) by dove.gmc.net (192.168.40.18) with Microsoft SMTP Server id 8.1.358.0; Thu, 2 Apr 2009 09:26:40 +0200 Message-ID: From: =?iso-8859-1?Q?Petr_Mal=FD?= To: Date: Thu, 2 Apr 2009 09:26:22 +0200 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Windows Mail 6.0.6001.18000 X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6001.18049 X-Karma: unknown: X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: LF: Tune and match the ant for 50kHz...550kHz Content-Type: multipart/alternative; boundary="----=_NextPart_000_0098_01C9B375.164F96B0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.9 required=5.0 tests=HTML_30_40,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-IP: 193.82.116.20 ------=_NextPart_000_0098_01C9B375.164F96B0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi all, I want to make a small transmatch (RX, TX up to 10 Watts, or so) to tune LW=20= 41 m (or smaller T-ant) in the range 50 ... 550 kHz. I am not too good in theory... but I believe that the most efficient system=20= is the popular loading coil (home made variometer, and taps to find 50 Ohms=20= match). The simple variometer (cylindrical coil in another cylindrical coil) is easy= to make and works fine on 136kHz. However, it is possible to change inducta= nce in the range about 1:2 or 1:3 only, not much better. Therefore the redud= ant inductance is too high to fetch the ant to resonance on 550 kHz. Solution would be to make a more sophisticated variometer (best: sphere in s= phere) to reach the ratio 1:10 or so. Or, to use a different kind of network. Pi network, L network or T network.=20= BTW I would also prefer to use a rotary switch and solder twenty condensers=20= rather than to make twenty taps on a coil wound with litz wire... How did you solve this yourself? Thanks, 73, Petr, OK1FIG ------=_NextPart_000_0098_01C9B375.164F96B0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Hi all,

I want to make a small transmatch (RX, TX u= p to 10=20 Watts, or so) to tune LW 41 m (or smaller T-ant) in the range 50 ... 550=20 kHz.

I am not too good in theory... but I believ= e that=20 the most efficient system is the popular loading coil (home made=20 variometer, and taps to find 50 Ohms match).

The simple variometer (cylindrical coil in=20= another=20 cylindrical coil) is easy to make and works fine on 136kHz. However, it is=20 possible to change inductance in the range about 1:2 or 1:3 only, not much=20 better. Therefore the redudant inductance is too high to fetch the ant to=20 resonance on 550 kHz.

Solution would be to make a more sophistica= ted=20 variometer (best: sphere in sphere) to reach the ratio 1:10 or so.

Or, to use a different kind of network. Pi=20= network,=20 L network or T network. BTW I would also prefer to use a rotary switch and=20 solder twenty condensers rather than to make twenty taps on a coil= =20 wound with litz wire...

How did you solve this yourself?

Thanks, 73, Petr, OK1FIG

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