Return-Path: Received: from rly-md01.mx.aol.com (rly-md01.mail.aol.com [172.20.29.139]) by air-md10.mail.aol.com (v125.7) with ESMTP id MAILINMD104-8e44b0d4991376; Wed, 25 Nov 2009 10:13:39 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-md01.mx.aol.com (v125.7) with ESMTP id MAILRELAYINMD014-8e44b0d4991376; Wed, 25 Nov 2009 10:13:23 -0500 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NDJXI-0003UP-Ee for rs_out_1@blacksheep.org; Wed, 25 Nov 2009 15:12:04 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NDJXH-0003UG-UB for rsgb_lf_group@blacksheep.org; Wed, 25 Nov 2009 15:12:03 +0000 Received: from out1.ip09ir2.opaltelecom.net ([62.24.128.245]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1NDJXH-0001zE-42 for rsgb_lf_group@blacksheep.org; Wed, 25 Nov 2009 15:12:03 +0000 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AuAEAA7YDEtcGuLt/2dsb2JhbACCIS+LPgbIBYQyBA X-IronPort-AV: E=Sophos;i="4.47,286,1257120000"; d="scan'208,217";a="246962254" Received: from unknown (HELO xphd97xgq27nyf) ([92.26.226.237]) by out1.ip09ir2.opaltelecom.net with SMTP; 25 Nov 2009 15:11:57 +0000 Message-ID: <000b01ca6de1$9fb6b1a0$0401a8c0@xphd97xgq27nyf> From: "mal hamilton" To: References: <000c01ca6db1$04873810$0301a8c0@your91hoehfy9g> Date: Wed, 25 Nov 2009 15:11:54 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 X-Karma: unknown: X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: Class E pa Content-Type: multipart/alternative; boundary="----=_NextPart_000_0008_01CA6DE1.9F5C0E80" 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-IP: 193.82.116.20 ------=_NextPart_000_0008_01CA6DE1.9F5C0E80 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Tony The G3YXM designs are class D and not class E. I do not know of any am= ateur using class E except myself. There could be others of course but most favour class D probably becau= se they are more flexible as far as frequency is concerned. Class E is= a very narrow frequency PA design and more critical to set up, but on= ce adjusted properly using a scope to get the drain waveform perfected= it is a vy reliable PA. De Mal/G3KEV=20 ----- Original Message -----=20 From: Anton B=E4rtschi=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Wednesday, November 25, 2009 11:47 AM Subject: Re: LF: Class E pa Hi Mal I'm still using a Derivative of the Design from G3YXM's class E 1KW= TX on LF. Recently I've built a TX for 500 kHz using the same princip= le. It works great and delivers up to 500W. Unfortunately only into a= dummy load, because 500 kHz is still not allowed here in Switzerland.= But at least - I will be ready ;-) 73 de Toni, HB9ASB 2009/11/25 mal hamilton Ref recent discussion on the subject. I use a class E pa on 500 kcs and never get any trouble. As a general guide use high voltage fets and the fet V should be= rated at about 5 times the supply V and current about 3 times. You arrive at class E by careful design not by accident.=20 Having designed and built the PA for the required power and load= R usually 50 ohms adjust into a DL for correct waveform as displayed= on a 'scope, this is important otherwise V spikes and instability wil= l kill the fet.=20 Install a suitable antenna and match it with a suitable atu to 50= ohms so when you connect the TX/PA to the antenna they both match. Check the wave form again and any slight mismatch should be adjust= ed by the antenna atu and NOT the pa.=20 The load does not have to be 50 ohms but this is convenient when= testing with available test gear. High V fets give more realistic C and Inductor and R values. A goo= d range for fets is a psu giving 40 - 100 volts ie fets 500volts and= a suitable current rating depending on your power. requirements ie if= you need to draw 5 amps the fet should be rated 15 amps. These are the general guidelines and work well for me. Most amateurs seem to use class D amps whereas class E are rare. de Mal/G3KEV ------=_NextPart_000_0008_01CA6DE1.9F5C0E80 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Tony
The G3YXM designs are class D and not= class E. I do=20 not know of any amateur using class E except myself.
There could be others of course but= most favour=20 class D probably because they are more flexible as far as frequency=20 is concerned. Class E is a very narrow frequency PA design= and more=20 critical to set up, but once adjusted properly using a scope to get th= e drain=20 waveform perfected it is a vy reliable PA.
De Mal/G3KEV
 
----- Original Message -----
From:=20 Anton= B=E4rtschi=20
Sent: Wednesday, November 25,= 2009 11:47=20 AM
Subject: Re: LF: Class E pa

Hi Mal
I'm still using a Derivative of the Design= from=20 G3YXM's class E 1KW TX on LF. Recently I've built a TX for 500 kHz= using the=20 same principle. It works great and delivers up to 500W. Unfortunatel= y only=20 into a dummy load, because 500 kHz is still not allowed here in Swit= zerland.=20 But at least - I will be ready ;-)
73 de Toni, HB9ASB

2009/11/25 mal hamilton <= ;g3kevmal@talktalk.net>
Ref recent discussion on the=20 subject.
 
I use a class E pa on 500 kcs and= never get any=20 trouble.
As a general guide use high volta= ge fets and=20 the fet V should be rated at  about 5 times the supply V and= current=20 about 3 times.
You arrive at class E by careful= design not by=20 accident.
Having designed and built the PA= for the=20 required power and load R usually 50 ohms adjust into a= DL for=20 correct waveform as displayed on a 'scope, this is important other= wise V=20 spikes and instability will kill the fet.
Install a suitable antenna and ma= tch it with a=20 suitable atu to 50 ohms so when you connect the TX/PA to the anten= na they=20 both match.
Check the wave form again and any= slight=20 mismatch should be adjusted by the antenna atu and NOT the pa.
The load does=20 not have to be 50 ohms but this is convenient when testing with av= ailable=20 test gear.
High V fets give more realistic= C and Inductor=20 and R values. A good range for fets is a psu giving 40 - 100 volts= ie fets=20 500volts and a suitable current rating depending on your power. re= quirements=20 ie if you need to draw 5 amps the fet should be rated 15 amps.
These are the general guidelines= and work well=20 for me.
Most amateurs seem to use class= D amps whereas=20 class E are rare.
 
de Mal/G3KEV
 

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