Return-Path: Received: from mtain-da06.r1000.mx.aol.com (mtain-da06.r1000.mx.aol.com [172.29.64.78]) by air-mb05.mail.aol.com (v126.13) with ESMTP id MAILINMB051-a3834b4c58402e8; Tue, 12 Jan 2010 06:08:48 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-da06.r1000.mx.aol.com (Internet Inbound) with ESMTP id C5F9B38000275; Tue, 12 Jan 2010 06:08:46 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NUeb3-0008Rm-Kx for rs_out_1@blacksheep.org; Tue, 12 Jan 2010 11:07:37 +0000 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NUeb3-0008Rd-6I for rsgb_lf_group@blacksheep.org; Tue, 12 Jan 2010 11:07:37 +0000 Received: from out1.ip09ir2.opaltelecom.net ([62.24.128.245]) by relay3.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1NUeb1-0005Bk-27 for rsgb_lf_group@blacksheep.org; Tue, 12 Jan 2010 11:07:37 +0000 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: ArcEAGbmS0tOlCMj/2dsb2JhbACNSQbIW4QwBA X-IronPort-AV: E=Sophos;i="4.49,261,1262563200"; d="scan'208,217";a="421434920" Received: from unknown (HELO your91hoehfy9g) ([78.148.35.35]) by out1.ip09ir2.opaltelecom.net with SMTP; 12 Jan 2010 11:07:26 +0000 Message-ID: <003a01ca9377$6c872d30$0301a8c0@your91hoehfy9g> From: "mal hamilton" To: "rsgb" Date: Tue, 12 Jan 2010 11:07:26 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: LF: class E amp Content-Type: multipart/alternative; boundary="----=_NextPart_000_0037_01CA9377.6C4457D0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_20_30,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-sid: 3039ac1d404e4b4c583e2036 X-AOL-IP: 193.82.116.20 ------=_NextPart_000_0037_01CA9377.6C4457D0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Andy and Co To take advantage of ur 50V 25A psu for a class E amp the component va= lues for 1.25Kw would be C1 =3D 0.067164uF, C2 =3D 0.086306uF in serie= s with L1 =3D 1.57936uH. RL =3D 0.99234ohms, then a suitable step up transformer for say 50 ohm= s to match a suitable antenna via a LPF (several poles at this power= to supress the harmonic content).=20 A couple of suitable FETS in parallel wouldn do the trick. I built a= class E using 60V ht some years ago for LF and it is still going wel= l. Push pull as you know helps reduce the 2nd harmonic but maybe not as= much as you think, therefore a single ended approach is more robust= with a good LPF. I am sure you have all this information anyway for class E design.The= most critical part is setting the amp up using a 'scope to avoid V sp= ikes,=20 I have no protective ccts in place but my antenna is very stable and= unaffected by the WX. =20 73 de mal/g3kev ------=_NextPart_000_0037_01CA9377.6C4457D0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Andy and Co

To take advantage of ur 50V 25A psu= for a class E=20 amp the component values for 1.25Kw would be C1 =3D 0.067164uF, C2 =3D= 0.086306uF in=20 series with L1 =3D 1.57936uH.

RL =3D 0.99234ohms, then a suitable= step up=20 transformer for say 50 ohms to match a suitable antenna via a LPF (sev= eral poles=20 at this power to supress the harmonic content).

A couple of suitable FETS in parallel= wouldn=20 do the trick. I built a class E using 60V ht some= years=20 ago for LF and it is still going well.

Push pull as you know helps redu= ce the 2nd=20 harmonic but maybe not as much as you think, therefore a single= ended=20 approach is more robust with a good LPF.

I am sure you have all this info= rmation anyway=20 for class E design.The most critical part is setting the amp up using= a=20 'scope to avoid V spikes,

I have no protective ccts in place bu= t my=20 antenna is very stable and unaffected by the WX.

73 de mal/g3kev

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