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[195.171.43.25]) by mx.google.com with ESMTP id ur6si15950273wjc.38.2013.12.29.10.42.08 for ; Sun, 29 Dec 2013 10:42:08 -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 1VxL2a-0007hw-QB for rs_out_1@blacksheep.org; Sun, 29 Dec 2013 18:24:44 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1VxL2a-0007hn-6b for rsgb_lf_group@blacksheep.org; Sun, 29 Dec 2013 18:24:44 +0000 Received: from blu0-omc1-s19.blu0.hotmail.com ([65.55.116.30]) by relay1.thorcom.net with esmtp (Exim 4.77) (envelope-from ) id 1VxL2Y-0003Wh-0A for rsgb_lf_group@blacksheep.org; Sun, 29 Dec 2013 18:24:43 +0000 Received: from BLU180-W62 ([65.55.116.8]) by blu0-omc1-s19.blu0.hotmail.com with Microsoft SMTPSVC(6.0.3790.4675); Sun, 29 Dec 2013 10:24:40 -0800 X-TMN: [EZEr1BxF6aG86Ryo2AJL4BwUpkesAi8g] X-Originating-Email: [rjraide@hotmail.com] Message-ID: From: Bob Raide To: "rsgb_lf_group@blacksheep.org" Date: Sun, 29 Dec 2013 13:24:39 -0500 Importance: Normal In-Reply-To: <52C0630C.8090407@iup.uni-heidelberg.de> 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> <52C05731.3060401@freenet.de>,<52C0630C.8090407@iup.uni-heidelberg.de> MIME-Version: 1.0 X-OriginalArrivalTime: 29 Dec 2013 18:24:40.0160 (UTC) FILETIME=[3CC34E00:01CF04C3] X-Spam-Score: 1.2 (+) 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: Stefan; Is this amp shown capable of handling 300 + volts like your 137 amp that I believe is similar in design? Bob > Date: Sun, 29 Dec 2013 18:59:40 +0100 > From: Stefan.Schaefer@iup.uni-heidelberg.de > To: rsgb_lf_group@blacksheep.org > Subject: LF: MF PA > > Hi Wolf, > > What type of FETs are you using? The standard IRFPs? Many of them have > internal Z diodes, so no addional RC network or Z idode is needed. The > losses are there anyway, of course. > > In some older projects i also played with that critical working point, > i.e. where one FET shuts down and the other opens. I've tried simple RC > networks (series R, parallel C) with an 100 Ohm trimmer. That worked > reasonably but usually it is not even necessary. My small MF PA is using > a simple ICL7667 and 2x IRFZ48N (Reichelt...) without problems. > My large PA generates up to 1.2 kW, which is also enough to reach 1 W > ERP, https://dl.dropboxusercontent.com/u/19882028/MF/mod%20MF%20PA.jpg. > It was designed for field experiments (Field day) where MUCH more > inefficient antennas will be tested, e.g. in France, next year, if they > have the allocation then... > > 73, GL, Stefan/DK7FC > > Am 29.12.2013 18:09, schrieb wolf_dl4yhf: > > 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 [...] Content analysis details: (1.2 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [65.55.116.30 listed in list.dnswl.org] 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (rjraide[at]hotmail.com) 1.6 SUBJ_ALL_CAPS Subject is all capitals -0.0 SPF_PASS SPF: sender matches SPF record -0.4 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain 0.0 HTML_MESSAGE BODY: HTML included in message X-Scan-Signature: d5ac66e7920295f519efeb68ecc59e6f Content-Type: multipart/alternative; boundary="_fd6c6ae9-4646-4357-9ad9-ff0b354db0e6_" Subject: RE: LF: MF PA X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.6 required=5.0 tests=FORGED_HOTMAIL_RCVD, HTML_MESSAGE,SUBJ_ALL_CAPS,TO_ADDRESS_EQ_REAL 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: 1538 --_fd6c6ae9-4646-4357-9ad9-ff0b354db0e6_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Stefan=3B Is this amp shown capable of handling 300 + volts like your 137 amp that I = believe is similar in design? Bob =20 > Date: Sun=2C 29 Dec 2013 18:59:40 +0100 > From: Stefan.Schaefer@iup.uni-heidelberg.de > To: rsgb_lf_group@blacksheep.org > Subject: LF: MF PA >=20 > Hi Wolf=2C >=20 > What type of FETs are you using? The standard IRFPs? Many of them have=20 > internal Z diodes=2C so no addional RC network or Z idode is needed. The= =20 > losses are there anyway=2C of course. >=20 > In some older projects i also played with that critical working point=2C= =20 > i.e. where one FET shuts down and the other opens. I've tried simple RC=20 > networks (series R=2C parallel C) with an 100 Ohm trimmer. That worked=20 > reasonably but usually it is not even necessary. My small MF PA is using= =20 > a simple ICL7667 and 2x IRFZ48N (Reichelt...) without problems. > My large PA generates up to 1.2 kW=2C which is also enough to reach 1 W=20 > ERP=2C https://dl.dropboxusercontent.com/u/19882028/MF/mod%20MF%20PA.jpg.= =20 > It was designed for field experiments (Field day) where MUCH more=20 > inefficient antennas will be tested=2C e.g. in France=2C next year=2C if = they=20 > have the allocation then... >=20 > 73=2C GL=2C Stefan/DK7FC >=20 > Am 29.12.2013 18:09=2C schrieb wolf_dl4yhf: > > Hi Stefan=2C > > > > > > > Hmm=2C P ~ 300W? :-) > > > > Not really... the design goal was driving the PA with the 13.8 V=2C "20= =20 > > ampere" power supply. There actually is some stray inductance (despite= =20 > > using 17 mm wide copper foil) so the load "seen" by the drains is a=20 > > bit higher than 12 V / 20 A =3D 0.6 Ohm. The max DC input current is no= w=20 > > about 15 A=2C but that's ok for me. Also=2C after adding the first lowp= ass=20 > > (which transforms from 12.5 to 50 Ohms=2C at very 'moderate' RF=20 > > currents)=2C the waveform at the drains isn't such a nice square wave=20 > > but the HUF75343 can 'absorb' the very narrow spikes (80 ns long=2C and= =20 > > over 55 V) when none of the two FETs conduct for a very short time.=20 > > According to the datasheet (where the FET are mistreated by driving an= =20 > > inductive load=2C as a test) they should survive this=2C even without a= n=20 > > 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.=20 > > From experience with the old PA (in which the FETs were biased into=20 > > 'almost linear operation'=2C at the expense of efficiency)=2C it should= be=20 > > possible. > > > > > > 73=2C > > Wolf . > > > > > > > > > > > >> An alternative to the foil could be: 4x=20 > >> http://www.reichelt.de/index.html?ACTION=3D3=3BARTICLE=3D57209=3BSEARC= H=3DCLI=20 > >> 200/120 > >> > >> 73=2C Stefan > > >=20 = --_fd6c6ae9-4646-4357-9ad9-ff0b354db0e6_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Stefan=3B
Is this amp shown c= apable of handling 300 + volts like your 137 amp that I believe is similar = in design? Bob
 =3B
>=3B Date: Sun=2C 29 Dec 2013 18:59:40= +0100
>=3B From: Stefan.Schaefer@iup.uni-heidelberg.de
>=3B To: = rsgb_lf_group@blacksheep.org
>=3B Subject: LF: MF PA
>=3B
>= =3B Hi Wolf=2C
>=3B
>=3B What type of FETs are you using? The st= andard IRFPs? Many of them have
>=3B internal Z diodes=2C so no addio= nal RC network or Z idode is needed. The
>=3B losses are there anyway= =2C of course.
>=3B
>=3B In some older projects i also played wi= th that critical working point=2C
>=3B i.e. where one FET shuts down = and the other opens. I've tried simple RC
>=3B networks (series R=2C = parallel C) with an 100 Ohm trimmer. That worked
>=3B reasonably but = usually it is not even necessary. My small MF PA is using
>=3B a simp= le ICL7667 and 2x IRFZ48N (Reichelt...) without problems.
>=3B My larg= e PA generates up to 1.2 kW=2C which is also enough to reach 1 W
>=3B= ERP=2C https://dl.dropboxusercontent.com/u/19882028/MF/mod%20MF%20PA.jpg. =
>=3B It was designed for field experiments (Field day) where MUCH mor= e
>=3B inefficient antennas will be tested=2C e.g. in France=2C next = year=2C if they
>=3B have the allocation then...
>=3B
>=3B= 73=2C GL=2C Stefan/DK7FC
>=3B
>=3B Am 29.12.2013 18:09=2C schri= eb wolf_dl4yhf:
>=3B >=3B Hi Stefan=2C
>=3B >=3B
>=3B &g= t=3B
>=3B >=3B >=3B Hmm=2C P ~ 300W? :-)
>=3B >=3B
>= =3B >=3B Not really... the design goal was driving the PA with the 13.8 V= =2C "20
>=3B >=3B ampere" power supply. There actually is some stra= y inductance (despite
>=3B >=3B using 17 mm wide copper foil) so th= e load "seen" by the drains is a
>=3B >=3B bit higher than 12 V / 2= 0 A =3D 0.6 Ohm. The max DC input current is now
>=3B >=3B about 15= A=2C but that's ok for me. Also=2C after adding the first lowpass
>= =3B >=3B (which transforms from 12.5 to 50 Ohms=2C at very 'moderate' RF =
>=3B >=3B currents)=2C the waveform at the drains isn't such a nice= square wave
>=3B >=3B but the HUF75343 can 'absorb' the very narro= w spikes (80 ns long=2C and
>=3B >=3B over 55 V) when none of the t= wo FETs conduct for a very short time.
>=3B >=3B According to the d= atasheet (where the FET are mistreated by driving an
>=3B >=3B indu= ctive load=2C as a test) they should survive this=2C even without an
&g= t=3B >=3B RC snubber network or an extra Zener diode.
>=3B >=3B I = will find out soon - also if P ~ 150 W is enough to reach 1 W ERP.
>= =3B >=3B From experience with the old PA (in which the FETs were biased i= nto
>=3B >=3B 'almost linear operation'=2C at the expense of effici= ency)=2C it should be
>=3B >=3B possible.
>=3B >=3B
>= =3B >=3B
>=3B >=3B 73=2C
>=3B >=3B Wolf .
>=3B >= =3B
>=3B >=3B
>=3B >=3B
>=3B >=3B
>=3B >=3B
= >=3B >=3B>=3B An alternative to the foil could be: 4x
>=3B >= =3B>=3B http://www.reichelt.de/index.html?ACTION=3D3=3BARTICLE=3D57209=3B= SEARCH=3DCLI
>=3B >=3B>=3B 200/120
>=3B >=3B>=3B
>= =3B >=3B>=3B 73=2C Stefan
>=3B >=3B
>=3B
=
= --_fd6c6ae9-4646-4357-9ad9-ff0b354db0e6_--