Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by klubnl.pl (8.14.4/8.14.4/Debian-8+deb8u2) with ESMTP id vBOIBKWN019098 for ; Sun, 24 Dec 2017 19:11:21 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1eTAfd-00045u-VI for rs_out_1@blacksheep.org; Sun, 24 Dec 2017 18:06:45 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1eTAfd-00045l-CF for rsgb_lf_group@blacksheep.org; Sun, 24 Dec 2017 18:06:45 +0000 Received: from mail-wm0-x229.google.com ([2a00:1450:400c:c09::229]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1eTAfZ-0005mG-66 for rsgb_lf_group@blacksheep.org; Sun, 24 Dec 2017 18:06:44 +0000 Received: by mail-wm0-x229.google.com with SMTP id y82so31042506wmg.1 for ; Sun, 24 Dec 2017 10:06:40 -0800 (PST) X-DKIM-Result: Domain=gmail.com Result=Good and Known Domain DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to; bh=nrfVWCk7uaxpG+/hXbbh0A3Hzg56HLM51+3XmRPkiTg=; b=E5MMEHIzv7blJoXk0Wnm+YSRkq96M5plhQIYMX6kOuEkCFEAVQzCD2TVXrdBjOQ1Wh rSHbr2ypYjmLAoRkIp8jcm9cQ0GhicfbopY0uGMSjXK2STe2YdzGpA7UmG8U6o4mtBar TIdV4zC6pnDg1DUDDec74q4yrYYl0QRiq0bCZt8ASSxvFhQRsj55e8CMivq1fFafKCnI IcK0WTuQFGlSnGaFTUetN3/75CQETMnN7+4pzqkOfJ0uNpgXBPtJZWWG58l4YDSHv4Eg 2yUdUJRPmbMBGbZa8aANEpCCufTW+5etunUTc6Y8LbVQSFCiubPBRydlM8/U9tdvF9We KMJg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to; bh=nrfVWCk7uaxpG+/hXbbh0A3Hzg56HLM51+3XmRPkiTg=; b=SOCCfIUz2/PeqMAYhQuNV0qz2r3JWfpAfoDID37ixZPyJpgnmA1uiAF/nFpk5rzvR4 7dUxPO09BW6iccp3qXy9cAs563AIWP1fcYWPzzqNL1kVJfr6VtRX2nCb7vbyYGQ2tnKQ hINvdm2VcqkT+AJqbP7jkgoi/mf4H7hUhDyhAU2Q0bg+elj+JWe6XS6cTunE4buY0mdF gnTqIc3Sm75D/+JMf5cvtPeMC66MEz80ahWAv/IWEM7R47P4jS6wWNTzqiHP3LxpSBiJ MX24b0PlEDQFQD0cdnQ69gaxlDfDwtvf7JIcJiI3Oe2yhZFEe9o9a05bMnPkXJfHfQrD yilQ== X-Gm-Message-State: AKGB3mKDiuPMqTubGD9v35ypgSuiPVYDLzLnCUEpMvLxIFD6XSqbe0fJ 3nQz7DEToklhN8WcTp4sZf2FuoDXGFEbXh7pjH7wWA== X-Google-Smtp-Source: ACJfBouhkTZ6UH1HkZXO3J3jVuZ3FyMtgDN/jnntXAC9QCIP6k0WglQKkGxVx0MzKkicGIHptdKH8C0bBTNE+7ig0x4= X-Received: by 10.80.146.77 with SMTP id j13mr24274192eda.298.1514138800063; Sun, 24 Dec 2017 10:06:40 -0800 (PST) MIME-Version: 1.0 Received: by 10.80.177.54 with HTTP; Sun, 24 Dec 2017 10:06:39 -0800 (PST) In-Reply-To: References: <4ffc7958-810a-e4d2-7745-258a58338934@n1bug.com> <5A3AE81B.9010205@posteo.de> <5A3B8FB1.1020403@posteo.de> <7ee833a8-04b4-4712-d927-7eccf37eec14@n1bug.com> <5A3D9BC1.1040609@posteo.de> <6fa587ef-d5b0-6a67-b604-ba94144444f7@n1bug.com> <5A3E77DD.4090908@posteo.de> <103A2C60B87B4930A99ED33442E477AF@StevePC> <792271d9-34bb-3fb1-140c-c322015e2e9b@n1bug.com> <5A3F9D04.90800@posteo.de> From: Andy Talbot Date: Sun, 24 Dec 2017 18:06:39 +0000 Message-ID: To: rsgb_lf_group@blacksheep.org X-Spam-Score: 0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: The other thing about that circuit that is wrong is the power out specification for the turns ratio / loading resistance. For a single ended PA, Pout max = Vdd ^2 / 2 / RL. With a 9:1 (3:1 turns) transformer RL = 50 / 9 = 5.6 ohms So for a 13.8V suply (ignoring Vsaturation) that means an absolute maximum power output possible of 13.8^ / 2 / 5.6 = 17 Watts into a true 50 ohms load on the transformer output. [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (andy.g4jnt[at]gmail.com) 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: 18c0ce4cbca80559a8b22b14cd653174 Subject: Re: LF: TXing 2200m WSPR Content-Type: multipart/alternative; boundary="94eb2c0c3a56518867056119e976" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.5 required=5.0 tests=HTML_20_30,HTML_MESSAGE, MAILTO_TO_SPAM_ADDR 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 --94eb2c0c3a56518867056119e976 Content-Type: text/plain; charset="UTF-8" The other thing about that circuit that is wrong is the power out specification for the turns ratio / loading resistance. For a single ended PA, Pout max = Vdd ^2 / 2 / RL. With a 9:1 (3:1 turns) transformer RL = 50 / 9 = 5.6 ohms So for a 13.8V suply (ignoring Vsaturation) that means an absolute maximum power output possible of 13.8^ / 2 / 5.6 = 17 Watts into a true 50 ohms load on the transformer output. In practice the device will saturate with a volt or so across it, lowering the voltage swing and keeping power out to a lower value. If the peak swing is 12V, Pmax now drops to 12^2/2/5.6 = 13 watts Riccardo, I assume you mean 1:4 turns ratio, or 1:16 impedance transformation. That Means RL = 50/16 = 3.1 ohms and at 12V swing gives 23 watts out as you state I made a push-pull PA using a similar type of FET, but used a 28V supply and 1+1:2 transformer. It gives 40 - 50 Watts over the frequency range 100kHz to 2MHz http://www.g4jnt.com/Linear_LF_PA3.pdf Andy G4JNT On 24 December 2017 at 17:33, Riccardo Zoli wrote: > > Hi Paul, Stefan > > my first PA for MF and LF, based on a IRF520, was similar. > However, I used a most appropriate 1:4 output transformer instead a 1:9. > With 13.8V, a 50mA bias current is more than adequate for AB class. You > could obtain about 20-22W max on output. > Obiviously, more supply voltage it means more power output. > > Merry XMAS & HNY! > > All the best > > > 73 de Riccardo IW4DXW > > > Il 24/Dic/2017 13:30, "DK7FC" ha scritto: > >> Hi Paul, >> >> Am 23.12.2017 23:36, schrieb N1BUG: >> >>> For anyone trying to follow along, this is my current version: >>> >>> http://n1bug.com/ASB_LF_Amp-20171223.jpg >>> >> >> The circuit looks good to me now. Maybe it helps to use a low pass filter >> in T configuration instead of a PI config. The T config starts with a >> series L. The PI config starts with a parallel C. That could make a >> significant difference for the harmonics. >> >> 73 and Merry christmas, Stefan >> >> --94eb2c0c3a56518867056119e976 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
The other thing about that circuit that is wrong is the po= wer out specification for the turns ratio / loading resistance.

For a single ended PA, Pout max =3D Vdd ^2 / 2 / RL.=C2=A0 =C2=A0Wi= th a 9:1 (3:1 turns) transformer RL =3D 50 / 9 =3D 5.6 ohms
So fo= r a 13.8V suply (ignoring Vsaturation) that means=C2=A0 an absolute maximum= power output possible of 13.8^=C2=A0 / 2 / 5.6 =3D 17 Watts into a true 50= ohms load on the transformer output.

In practice = the device will saturate with a volt or so across it, lowering the voltage = swing and keeping power out to a lower value.=C2=A0 =C2=A0If the peak swing= is 12V, Pmax now drops to 12^2/2/5.6 =3D 13 watts

=C2=A0Riccardo, I assume you mean 1:4 turns ratio,=C2=A0 or 1:16 impedance= transformation.=C2=A0 =C2=A0That Means RL =3D 50/16 =3D 3.1 ohms and at 12= V swing gives 23 watts out as you state

I made a p= ush-pull PA using a similar=C2=A0 type of FET, but used a 28V supply and 1+= 1:2 transformer.=C2=A0 It gives 40 - 50 Watts over the frequency range=C2= =A0 100kHz to 2MHz


Andy=C2=A0 G4JNT

On 24 December 2017 at 17:33, Riccardo Zoli <= riccardozoli80@gmail.com> wrote:

Hi Paul, Stefan=C2=A0

my first PA for MF and LF, based on a IRF520, was similar.
However, I used a most appropriate 1:4 output transforme= r instead a 1:9. With 13.8V, a 50mA bias current is more than adequate for = AB class. You could obtain about 20-22W max on output.
Obiviously, more supply voltage it means more power output.

Merry XMAS & HNY!

All the best
<= br>

73 de Riccardo IW4DX= W


Il 24/Dic/2017 13:30, "DK7FC" <selberdenken@posteo.de= > ha scritto:
Hi Paul,

Am 23.12.2017 23:36, schrieb N1BUG:
For anyone trying to follow along, this is my current version:

http://n1bug.com/ASB_LF_Amp-20171223.jpg

The circuit looks good to me now. Maybe it helps to use a low pass filter i= n T configuration instead of a PI config. The T config starts with a series= L. The PI config starts with a parallel C. That could make a significant d= ifference for the harmonics.

73 and Merry christmas, Stefan


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