Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-da02.r1000.mx.aol.com (Internet Inbound) with ESMTP id 3DA1338000095; Tue, 5 Feb 2013 08:47:55 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1U2irG-0000gH-JS for rs_out_1@blacksheep.org; Tue, 05 Feb 2013 13:46:46 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1U2irF-0000g8-TX for rsgb_lf_group@blacksheep.org; Tue, 05 Feb 2013 13:46:45 +0000 Received: from out1.ip01ir2.opaltelecom.net ([62.24.128.237]) by relay1.thorcom.net with esmtp (Exim 4.77) (envelope-from ) id 1U2irC-0007N4-VU for rsgb_lf_group@blacksheep.org; Tue, 05 Feb 2013 13:46:44 +0000 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Al8JAD8MEVFcF/xB/2dsb2JhbABFFoIzpSsDlmIEgQEXc4IaBQEBAwEBCAEBA0kCJgYBAQMFAgEDEQQBAQolFAEECBIGFggGEwoBAgIBAYduAwkKCKoMhkgNiVaMFoEdBRmECgOIMIVXhkIEgnGKIoUTgn4 X-IronPort-AV: E=Sophos;i="4.84,602,1355097600"; d="scan'208,217";a="418156248" Received: from host-92-23-252-65.as13285.net (HELO xphd97xgq27nyf) ([92.23.252.65]) by out1.ip01ir2.opaltelecom.net with SMTP; 05 Feb 2013 13:46:22 +0000 Message-ID: <003d01ce03a7$2c9b4c80$0401a8c0@xphd97xgq27nyf> From: "mal hamilton" To: References: <002801ce039a$adff7510$0401a8c0@xphd97xgq27nyf> <1360070559.34662.YahooMailNeo@web133206.mail.ir2.yahoo.com> Date: Tue, 5 Feb 2013 13:46:17 -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-Spam-Score: 2.3 (++) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Pete I have built and used class E amps for years and have always succeeded in getting a rounded off trailing edge presentation on the scope. If the amp is aligned properly as per Sokai instructions the perfect Drain wave is achievable otherwise the voltage spikes present will kill the Fet eventually. If it is used in a QRP rig of a few watts with a hefty FET I expect you will get away with it but then it is not really class E. g3kev [...] Content analysis details: (2.3 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 SPF_PASS SPF: sender matches SPF record 0.0 HTML_MESSAGE BODY: HTML included in message 2.3 AXB_XMAILER_MIMEOLE_OL_024C2 AXB_XMAILER_MIMEOLE_OL_024C2 X-Scan-Signature: 94b4899eb522d3cd83a8c4d63d16b91e Subject: Re: LF: Re: My transmit converter description Content-Type: multipart/alternative; boundary="----=_NextPart_000_003A_01CE03A7.2C3BEE70" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.8 required=5.0 tests=HTML_30_40,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: 3039ac1d404a51110d8a49cb 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_003A_01CE03A7.2C3BEE70 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Pete I have built and used class E amps for years and have always succeeded = in getting a rounded off trailing edge presentation on the scope. If the amp is aligned properly as per Sokai instructions the perfect = Drain wave is achievable otherwise the voltage spikes present will kill = the Fet eventually. If it is used in a QRP rig of a few watts with a = hefty FET I expect you will get away with it but then it is not really = class E. g3kev ----- Original Message -----=20 From: M0FMT=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Tuesday, February 05, 2013 1:22 PM Subject: Re: LF: Re: My transmit converter description Hi Mal and group The Drain wave trailing edge spike is shown clearly in this PDF on = microwave Class e amps although microwave the principle applies to MF as = well. In the PDF, Nathan O. Sokal author, has produced a IMHO cool chart = to track the changes necessary to produce the near perfect Drain wave. = To save reading the whole thing scroll to the end of the article and see = the chart. I have played with the drain wave on one or two HB amps and the chart = works as advertised.... no sums just cut and try! = http://www.cs.berkeley.edu/~culler/AIIT/papers/radio/Sokal%20AACD5-powera= mps.pdf 73 es GL Pete M0FMT IO91UX From: mal hamilton To: rsgb_lf_group@blacksheep.org=20 Sent: Tuesday, 5 February 2013, 12:16 Subject: LF: Re: My transmit converter description Dimitris Your 'scope shot of the signal after the low pass filter shows a = Voltage spike which should not be there for a class E amplifier. This needs = to be smoothed out otherwise you wil eventually Zap the PA Fet. You need to adjust L2 to correct this problem. de Mal/G3KEV ----- Original Message ----- From: "Dimitrios Tsifakis" To: Sent: Tuesday, February 05, 2013 12:50 AM Subject: LF: My transmit converter description > Hello group, > > My transmit converter is now finished and tested - it survived two > sessions of 50% duty cycle WSPR transmissions on 475 kHz and the > results are great. I thought others may find this useful, so I = have > put a write-up on my web page: > > http://people.physics.anu.edu.au/~dxt103/472/nltt/ > > It is a 50 W class-e PA designed for 50 ohm impedance, so there is = no > need for an impedance transformer. Doesn't get simpler than that = :-) > The driving circuit is based on G3XBM Roger's design with the > difference of a 10 MHz OCXO LO and the addition of a beefy MOSFET > driver. > > 73, Dimitris VK1SV > ------=_NextPart_000_003A_01CE03A7.2C3BEE70 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Pete
I have built and used class E amps for years and = have=20 always succeeded in getting a rounded off  trailing edge = presentation on=20 the scope.
If the amp is aligned properly as per Sokai = instructions=20 the perfect Drain wave is achievable otherwise the voltage spikes = present will=20 kill the Fet eventually. If it is used in a QRP rig of a few watts with = a hefty=20 FET I expect you will get away with it but then it is not really class=20 E.
g3kev
 
 
----- Original Message -----
From:=20 M0FMT
Sent: Tuesday, February 05, = 2013 1:22=20 PM
Subject: Re: LF: Re: My = transmit=20 converter description

Hi Mal and=20 group
 
The Drain=20 wave trailing edge spike is shown clearly in this PDF on = microwave Class=20 e amps although microwave the principle applies to MF as well. In = the=20 PDF, Nathan O. Sokal author, has produced a IMHO cool = chart to=20 track the changes necessary to produce the near perfect Drain wave. To = save=20 reading the whole thing scroll to the end of the article and see the=20 chart.
I have played with the drain = wave on one=20 or two HB amps and the chart works as advertised.... no sums just cut = and=20 try!   http://www.cs.berkeley.edu/~culler/AIIT/papers/radio/Sok= al%20AACD5-poweramps.pdf
73 es GL Pete M0FMT IO91UX
From:=20 mal hamilton <g3kevmal@talktalk.net>
To: = rsgb_lf_group@blacksheep.org=20
Sent: Tuesday, 5 = February=20 2013, 12:16
Subject: LF:=20 Re: My transmit converter = description

Dimitris
Your=20 'scope shot of the signal after the low pass filter shows a = Voltage
spike=20 which should not be there for a class E amplifier. This needs to=20 be
smoothed out otherwise you wil eventually Zap the PA = Fet.
You need=20 to adjust L2 to correct this problem.
de Mal/G3KEV

----- = Original=20 Message -----
From: "Dimitrios Tsifakis" <dtsifakis@gmail.com>
To:= =20 <rsgb_lf_group@blacksheep.= org>
Sent:=20 Tuesday, February 05, 2013 12:50 AM
Subject: LF: My transmit = converter=20 description


> Hello group,
>
> My transmit = converter is now finished and tested - it survived two
> = sessions of=20 50% duty cycle WSPR transmissions on 475 kHz and the
> results = are=20 great. I thought others may find this useful, so I have
> put = a=20 write-up on my web page:
>
> http://people.physics.anu.edu.au/~dxt103/472/nltt/>
>=20 It is a 50 W class-e PA designed for 50 ohm impedance, so there is=20 no
> need for an impedance transformer. Doesn't get simpler = than that=20 :-)
> The driving circuit is based on G3XBM Roger's design = with=20 the
> difference of a 10 MHz OCXO LO and the addition of a = beefy=20 MOSFET
> driver.
>
> 73, Dimitris=20 = VK1SV
>




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