Return-Path: X-Spam-DCC: paranoid 1290; Body=3 Fuz1=3 Fuz2=3 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-0.2 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_40_50,HTML_MESSAGE,RATWARE_GECKO_BUILD,SPF_PASS autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id u3QFZCMo026855 for ; Tue, 26 Apr 2016 17:35:12 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1av4uc-0006vq-8z for rs_out_1@blacksheep.org; Tue, 26 Apr 2016 16:28:30 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1av4ub-0006vh-Tl for rsgb_lf_group@blacksheep.org; Tue, 26 Apr 2016 16:28:29 +0100 Received: from mailfe05.swip.net ([212.247.154.129] helo=swip.net) by relay1.thorcom.net with esmtp (Exim 4.87) (envelope-from ) id 1av4uZ-0006pG-K2 for rsgb_lf_group@blacksheep.org; Tue, 26 Apr 2016 16:28:28 +0100 X-T2-Spam-Status: No, hits=0.9 required=5.0 tests=BAYES_50, HTML_MESSAGE Received: from [81.224.101.198] (account cxu-dcw-tyr@tele2.se HELO [192.168.1.8]) by mailfe05.swip.net (CommuniGate Pro SMTP 5.4.4) with ESMTPSA id 659916796 for rsgb_lf_group@blacksheep.org; Tue, 26 Apr 2016 17:28:26 +0200 References: <57101A93.9050904@posteo.de> <8D364FDC57083E1-13C0-757EEB@webmail-vm186.sysops.aol.com> <5710A5DD.7040300@abelian.org> <5710BCBA.60901@posteo.de> <5711387D.7070600@abelian.org> <57134ADA.1020309@abelian.org> <5713EABF.70601@abelian.org> <5713EE10.3000008@posteo.de> <571BA7FE.6080601@posteo.de> <571F86BF.5050403@tele2.se> To: rsgb_lf_group@blacksheep.org From: Johan Bodin Message-ID: <571F891B.3010109@tele2.se> Date: Tue, 26 Apr 2016 17:28:27 +0200 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.7.2 MIME-Version: 1.0 In-Reply-To: <571F86BF.5050403@tele2.se> X-HELO-Warning: Remote host 212.247.154.129 (mailfe05.swip.net) used invalid HELO/EHLO swip.net - verification failed X-Scan-Signature: ab7de7439a3fce0b74220375dc6f18e8 Subject: Re: LF: TXing on VLF again, my first homemade linear PA! :-) Content-Type: multipart/alternative; boundary="------------000206060908080806040900" 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-Scanned-By: MIMEDefang 2.56 on 10.1.3.11 Status: O X-Status: X-Keywords: X-UID: 7858 This is a multi-part message in MIME format. --------------000206060908080806040900 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Even more linear QRO for dreamer's band: http://www.ti.com/lit/ds/symlink/tas5630b.pdf Den 2016-04-26 kl. 17:18, skrev Johan Bodin: > Hi Stefan > > I thought about your 9kHz PA efforts when I found this class D PWM > chip capable of ~300W up to 100kHz with very low distorsion. Amazing > performance from such a small $6 SMD chip! > > http://www.ti.com/lit/ds/symlink/tpa3251.pdf > > 73 de > Johan SM6LKM > > Den 2016-04-23 kl. 18:51, skrev DK7FC: >> Hi all, >> >> Since about 16 UTC i'm transmitting on 8270.00500 Hz again. The >> antenna current is about 200 mA. It is a first test over a longer >> time with my new PA. >> >> I have been off the air for a few days now becuase i destroyed my >> audio amp that i used as a VLF PA. Somehow i started to like the idea >> of a clean sine wave coming from the PA. Low pass filters are hard to >> design for VLF, you know. Since i don't like buying and since i >> didn't find another one in the trash, i 'had to' (actually /wanted/) >> to build my own. It is a class-AB PA now running at 20V DC using 2x >> IRFP064N against ground. Opposite phase drive signals are generated >> by a small blue ferrite core with 20 quadfilar turns. On the primary >> side, 2 of these 4 windings are in series. On the scope, the signal >> looks quite good. The 3rd harmonic is at about -20 dBc, certainly >> improvable. But it's just version 0.2 now ;-) >> A large ferrite core is used to up-transform the voltage to about >> 220V rms for this power level (i'm not spot on the resonance), also >> providing galvanic decoupling. >> >> A photo can be found at >> https://dl.dropboxusercontent.com/u/19882028/VLF/20160423_184046.jpg >> https://dl.dropboxusercontent.com/u/19882028/VLF/20160423_184059.jpg >> >> The PA consumes 3.6A at 20V DC now. Improvements will follow... >> >> The signal will stay on air for a few hours now. >> >> 73, Stefan > --------------000206060908080806040900 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 8bit Even more linear QRO for dreamer's band:

  http://www.ti.com/lit/ds/symlink/tas5630b.pdf


Den 2016-04-26 kl. 17:18, skrev Johan Bodin:
Hi Stefan

I thought about your 9kHz PA efforts when I found this class D PWM chip capable of ~300W up to 100kHz with very low distorsion.  Amazing performance from such a small $6 SMD chip!

http://www.ti.com/lit/ds/symlink/tpa3251.pdf

73 de
Johan SM6LKM

Den 2016-04-23 kl. 18:51, skrev DK7FC:
Hi all,

Since about 16 UTC i'm transmitting on 8270.00500 Hz again. The antenna current is about 200 mA. It is a first test over a longer time with my new PA.

I have been off the air for a few days now becuase i destroyed my audio amp that i used as a VLF PA. Somehow i started to like the idea of a clean sine wave coming from the PA. Low pass filters are hard to design for VLF, you know. Since i don't like buying and since i didn't find another one in the trash, i 'had to' (actually wanted) to build my own. It is a class-AB PA now running at 20V DC using 2x IRFP064N against ground. Opposite phase drive signals are generated by a small blue ferrite core with 20 quadfilar turns. On the primary side, 2 of these 4 windings are in series. On the scope, the signal looks quite good. The 3rd harmonic is at about -20 dBc, certainly improvable. But it's just version 0.2 now ;-)
A large ferrite core is used to up-transform the voltage to about 220V rms for this power level (i'm not spot on the resonance), also providing galvanic decoupling.

A photo can be found at
https://dl.dropboxusercontent.com/u/19882028/VLF/20160423_184046.jpg
https://dl.dropboxusercontent.com/u/19882028/VLF/20160423_184059.jpg

The PA consumes 3.6A at 20V DC now. Improvements will follow...

The signal will stay on air for a few hours now.

73, Stefan


--------------000206060908080806040900--