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[195.171.43.25]) by mx.google.com with ESMTP id z18si16612818wij.82.2013.12.29.09.26.03 for ; Sun, 29 Dec 2013 09:26:03 -0800 (PST) Received-SPF: neutral (google.com: 195.171.43.25 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) client-ip=195.171.43.25; Authentication-Results: mx.google.com; spf=neutral (google.com: 195.171.43.25 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) smtp.mail=owner-rsgb_lf_group@blacksheep.org Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1VxJtz-0006tI-M8 for rs_out_1@blacksheep.org; Sun, 29 Dec 2013 17:11:47 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1VxJtz-0006t9-7D for rsgb_lf_group@blacksheep.org; Sun, 29 Dec 2013 17:11:47 +0000 Received: from mout0.freenet.de ([195.4.92.90]) by relay1.thorcom.net with esmtps (UNKNOWN:AES256-GCM-SHA384:256) (Exim 4.77) (envelope-from ) id 1VxJtx-0003Ez-Eb for rsgb_lf_group@blacksheep.org; Sun, 29 Dec 2013 17:11:46 +0000 Received: from [195.4.92.142] (helo=mjail2.freenet.de) by mout0.freenet.de with esmtpa (ID dl4yhf@freenet.de) (port 25) (Exim 4.80.1 #4) id 1VxJtw-0002ap-E4 for rsgb_lf_group@blacksheep.org; Sun, 29 Dec 2013 18:11:44 +0100 Received: from localhost ([::1]:47120 helo=mjail2.freenet.de) by mjail2.freenet.de with esmtpa (ID dl4yhf@freenet.de) (Exim 4.80.1 #4) id 1VxJtw-0007aH-6X for rsgb_lf_group@blacksheep.org; Sun, 29 Dec 2013 18:11:44 +0100 Received: from mx6.freenet.de ([195.4.92.16]:33889) by mjail2.freenet.de with esmtpa (ID dl4yhf@freenet.de) (Exim 4.80.1 #4) id 1VxJrQ-0006ql-Mc for rsgb_lf_group@blacksheep.org; Sun, 29 Dec 2013 18:09:08 +0100 Received: from blfd-4d080c18.pool.mediaways.net ([77.8.12.24]:2605 helo=[192.168.178.21]) by mx6.freenet.de with esmtpsa (ID dl4yhf@freenet.de) (TLSv1:DHE-RSA-CAMELLIA256-SHA:256) (port 465) (Exim 4.80.1 #4) id 1VxJrQ-0001Ip-81 for rsgb_lf_group@blacksheep.org; Sun, 29 Dec 2013 18:09:08 +0100 Message-ID: <52C05731.3060401@freenet.de> Date: Sun, 29 Dec 2013 18:09:05 +0100 From: wolf_dl4yhf User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:17.0) Gecko/20130620 Thunderbird/17.0.7 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <20C550A7D07741688C6A26E73CBCF741@White> <52BF4895.8080502@iup.uni-heidelberg.de> <52BF7E2A.9000002@iup.uni-heidelberg.de> <52BFD963.8020300@freenet.de> <8C09023FA2074CB380BC9CF1E7A514E3@White> <52C00514.4030805@freenet.de> <52C04A0A.5070101@iup.uni-heidelberg.de> In-Reply-To: <52C04A0A.5070101@iup.uni-heidelberg.de> X-Originated-At: 77.8.12.24!2605 X-Spam-Score: -0.4 (/) 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: Hi Stefan, > Hmm, P ~ 300W? :-) Not really... the design goal was driving the PA with the 13.8 V, "20 ampere" power supply. There actually is some stray inductance (despite using 17 mm wide copper foil) so the load "seen" by the drains is a bit higher than 12 V / 20 A = 0.6 Ohm. The max DC input current is now about 15 A, but that's ok for me. Also, after adding the first lowpass (which transforms from 12.5 to 50 Ohms, at very 'moderate' RF currents), the waveform at the drains isn't such a nice square wave but the HUF75343 can 'absorb' the very narrow spikes (80 ns long, and over 55 V) when none of the two FETs conduct for a very short time. According to the datasheet (where the FET are mistreated by driving an inductive load, as a test) they should survive this, even without an RC snubber network or an extra Zener diode. I will find out soon - also if P ~ 150 W is enough to reach 1 W ERP. From experience with the old PA (in which the FETs were biased into 'almost linear operation', at the expense of efficiency), it should be possible. [...] Content analysis details: (-0.4 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [195.4.92.90 listed in list.dnswl.org] 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (dl4yhf[at]freenet.de) -0.4 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain X-Scan-Signature: 739d4fb39bd02fc5a2de5437a39bb056 Subject: Re: LF: VLF exciter Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=none 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 Status: O X-Status: X-Keywords: X-UID: 3162 Hi Stefan, > Hmm, P ~ 300W? :-) Not really... the design goal was driving the PA with the 13.8 V, "20 ampere" power supply. There actually is some stray inductance (despite using 17 mm wide copper foil) so the load "seen" by the drains is a bit higher than 12 V / 20 A = 0.6 Ohm. The max DC input current is now about 15 A, but that's ok for me. Also, after adding the first lowpass (which transforms from 12.5 to 50 Ohms, at very 'moderate' RF currents), the waveform at the drains isn't such a nice square wave but the HUF75343 can 'absorb' the very narrow spikes (80 ns long, and over 55 V) when none of the two FETs conduct for a very short time. According to the datasheet (where the FET are mistreated by driving an inductive load, as a test) they should survive this, even without an RC snubber network or an extra Zener diode. I will find out soon - also if P ~ 150 W is enough to reach 1 W ERP. From experience with the old PA (in which the FETs were biased into 'almost linear operation', at the expense of efficiency), it should be possible. 73, Wolf . > An alternative to the foil could be: 4x > http://www.reichelt.de/index.html?ACTION=3;ARTICLE=57209;SEARCH=CLI > 200/120 > > 73, Stefan