Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dk03.r1000.mx.aol.com (Internet Inbound) with ESMTP id 61441380000A3; Fri, 29 Jun 2012 09:08:48 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Skav3-0001fm-Sa for rs_out_1@blacksheep.org; Fri, 29 Jun 2012 14:07:29 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Skav2-0001fd-Nf for rsgb_lf_group@blacksheep.org; Fri, 29 Jun 2012 14:07:28 +0100 Received: from out1.ip03ir2.opaltelecom.net ([62.24.128.239]) by relay1.thorcom.net with esmtp (Exim 4.77) (envelope-from ) id 1Skauy-000484-PN for rsgb_lf_group@blacksheep.org; Fri, 29 Jun 2012 14:07:27 +0100 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AosFAPCn7U9Ok8ZS/2dsb2JhbABFAwqCOIJGT5sEk1kBAYIdgQiCEwUBAQUIAQECARYzAiwBAQMFAgEBAhEEAQEKFwEGAwICFAEEGgYNCQgGEwoBAgIBAYdsAw8HpSaDTYQqjxSKU2QFBRABhF2BEgONTpJohQCCX4Ff X-IronPort-AV: E=Sophos;i="4.77,498,1336345200"; d="scan'208,217";a="391391792" Received: from host-78-147-198-82.as13285.net (HELO xphd97xgq27nyf) ([78.147.198.82]) by out1.ip03ir2.opaltelecom.net with SMTP; 29 Jun 2012 14:07:22 +0100 Message-ID: <004a01cd55f8$1e6b47d0$0401a8c0@xphd97xgq27nyf> From: "mal hamilton" To: References: <4FEB8A2F.3030504@iup.uni-heidelberg.de> <7E7DFBB4D102A04DB5ADC88D66628A4A0FAB65D1@ICTS-S-MBX5.luna.kuleuven.be> <82ECFF6D94B94BED9D93B5580549A409@Extensa> <1340872602.49196.YahooMailNeo@web171602.mail.ir2.yahoo.com> <4FEC18F4.9050608@online.fr> <1340875355.96079.YahooMailNeo@web171602.mail.ir2.yahoo.com> <1340876781.29716.YahooMailNeo@web171601.mail.ir2.yahoo.com> <4FEC7DDF.8050906@iup.uni-heidelberg.de>,<1340908899.62897.YahooMailNeo@web171605.mail.ir2.yahoo.com> <7E7DFBB4D102A04DB5ADC88D66628A4A0FAB71D7@ICTS-S-MBX5.luna.kuleuven.be> <1340969485.35762.YahooMailNeo@web171603.mail.ir2.yahoo.com> Date: Fri, 29 Jun 2012 13:07:21 -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: 3.1 (+++) 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 find for a class E PA or class C with series resonant cct at frequency of interest you do not need a LPF. To resonate the PA use an Air core inductor and fixed capicator ie for 500 Khz use 5nF in series with 20uH inductor. Adjust inductor slightly up/down in value to resonate at exact freq of interest. Use an old LOPT core 8 turns Prim 24 turns Sec. The wire does not have to be Litz. Prim 2.5mm elec wire and Sec 1mm. I have used both litz and elec wire and find no difference. A couple of hours should build this type of TX [...] Content analysis details: (3.1 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [62.24.128.239 listed in list.dnswl.org] 0.0 FSL_XM_419 Old OE version in X-Mailer only seen in 419 spam -0.0 SPF_PASS SPF: sender matches SPF record 0.0 HTML_MESSAGE BODY: HTML included in message 1.6 FSL_UA FSL_UA 1.5 AXB_XMAILER_MIMEOLE_OL_024C2 AXB_XMAILER_MIMEOLE_OL_024C2 X-Scan-Signature: 6b82e6b293537342548040dfe5d175a5 Subject: Re: LF: Re: RE: 472 kHz PA running at 12 VDC Content-Type: multipart/alternative; boundary="----=_NextPart_000_0047_01CD55F8.1E393B50" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.4 required=5.0 tests=HTML_50_60,HTML_FONTCOLOR_BLUE, HTML_FONT_BIG,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-SCOLL-SCORE: 1:2:508620352:93952408 X-AOL-SCOLL-URL_COUNT: 1 x-aol-sid: 3039ac1db4074feda8df1d88 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_0047_01CD55F8.1E393B50 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Pete I find for a class E PA or class C with series resonant cct at frequency = of interest you do not need a LPF. To resonate the PA use an Air core inductor and fixed capicator ie for = 500 Khz use 5nF in series with 20uH inductor. Adjust inductor slightly = up/down in value to resonate at exact freq of interest. Use an old LOPT = core 8 turns Prim 24 turns Sec. The wire does not have to be Litz. Prim = 2.5mm elec wire and Sec 1mm. I have used both litz and elec wire and = find no difference. A couple of hours should build this type of TX g3kev =20 ----- Original Message -----=20 From: M0FMT=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Friday, June 29, 2012 11:31 AM Subject: Re: LF: Re: RE: 472 kHz PA running at 12 VDC Hi Rik Many thanks for your very useful information. I hope others find this = as well. Yes I said in an earlier mail what the PA and driver would cost from = E-bay (my supplier of choice... :o)) but at least they are obtainable. The current hold are the Ferrites or the Iron Dust toriods. This is = the usual problem because one black iron ring looks very much like = another. Once you have it in your hands you can do a test. What I do is = to put a few turns on an unknown core and measure the inductance then = compare the results with the theoretical value obtained from a range of = cores with the same dimensions using "Mini Core" SW. At the moment I = have a source for the T1 core but not the choke. And surprisingly I = can't find the T80-2s they were every where once upon a time. Anyway I = do have a variety of cores that will probably do for the O/P filtre. One = day I will find a design I can kit perfectly. I like your transverter, I am getting torn between projects right now. = Q6 / Q7 driver as you say can be reproduced for each FET gate cheaply in = fact I have the parts! I will now crawl into my cave and start to build. Thanks to you and = Stefan. 73 es GL Pete M0FMT IO91UX From: Rik Strobbe To: "rsgb_lf_group@blacksheep.org" =20 Sent: Friday, 29 June 2012, 8:49 Subject: RE: LF: Re: RE: 472 kHz PA running at 12 VDC =20 Hello Pete, I assume that the more exotic parts are the power FET (IRFZ48N) and = the driver IC (ICL7667). The IRFZ48N is a 55V / 64A / 0.014 Ohm device. For a first try you = could replace it by far more common IRF460 that is 100V / 28A / 0.06 = Ohm. A bit of reverse engineering: Stefan states 50W output at 80% = efficiency =3D 62.5W input =3D 5.2A at 12V. So with a 28A device you are on the safe side. The larger Ron (0.06 Ohm vs 0.014 Ohm) will (in theory) reduce the = efficiency. But 5.2A in 0.014 Ohm is only about 0.4W loss (for a = IRFZ48N). For a IRF460 it is 5.2A in 0.06 Ohm =3D 1.6W loss. So the losses (12.5W) are probably more due to the non perfect = switching than due to the Ron of the FETs. An alternative for the ICL7667 is a TC4426 or a homebrew driver (see = http://www.pa3bca.nl/images/stories/500KHz/500khz_transverter_full.gif/im= ages/stories/500KHz/500khz_transverter_full.gif). 73, Rik ON7YD - OR7T Van: owner-rsgb_lf_group@blacksheep.org = [owner-rsgb_lf_group@blacksheep.org] namens M0FMT [m0fmt@yahoo.co.uk] Verzonden: donderdag 28 juni 2012 20:41 Aan: rsgb_lf_group@blacksheep.org Onderwerp: Re: LF: Re: RE: 472 kHz PA running at 12 VDC Hi Stefan I like this and would like to make to make it. I so far have tracked = down most bits but as usual the Unobtainium of so many construction = projects that fall at the last hurdle unless they are Kits........ no = chance of that I suppose? There will be those who tell me its easy to get the bits but unless = you work for a company that uses this stuff it can not be slipped = through the "Purchasing" it becomes a positive stop!!=20 Like the Litz I just put that in one of our big outfits with min = orders and it said it had over one hundred thousand Litz and promptly = collapsed. But they have one of the toroids (T1) wow and its not a min = order either double wow! Litz can be fabricated from 0.125 Cu/En? Hmm = it's plaited ? Wima caps are available from Maplin haven't checked in depth but they = usually are. I like the idea of using a DDS or Transceiver as a master osc source = div. by four. Generally I buy my power FETs by the hand full off E-bay they may not = be ideal but are cheap!! 50P (eer 60Ec) (Never mind the quality but feel = the width... principle) and the drivers TC range for slightly more. I'll keep searching for a bit but if anyone has a kitting list (UK = source) may be they could publish it?=20 And thanks Stefan nothing under the Sun is "New" but in context it is = new and worth while thanks! 73 es GL Pete M0FMT IO91UX From: Stefan Sch=C3=A4fer To: rsgb_lf_group@blacksheep.org=20 Sent: Thursday, 28 June 2012, 16:53 Subject: Re: LF: Re: RE: 472 kHz PA running at 12 VDC Hi MF,=20 Late at night, i made draw the schematic. Here it is: = https://dl.dropbox.com/u/19882028/MF/100W%20475kHz%20PA.png (picture of = prototype = https://dl.dropbox.com/u/19882028/MF/DK7FC%20472%20kHz%20PA%2015W%2B100W.= JPG) Most of the parts are not critical.=20 The ferrite cores are the blue EPCOS types, N30 material. Details are = in the image. But you may use a FT140-77 alternatively and double the = primary and secondary number of turns. There are many alternatives, also to the FETs. Instead of the IRZF48N = you may try a IRF1405. This one has a lower on-resistance but a higher = input capacity. Maybe it works even better, i didn't try to many parts. = Switching times are not critical. So you need to find a compromise = between low on resistance and input capacity while the Drain-Source = voltage should be 55V for a 12V supply. Instead of RF litz wire (i use this one: = http://www.reichelt.de/index.html?ACTION=3D3;ARTICLE=3D57206;SEARCH=3DCLI= %20200%2F30 ) you can also use 1mm diam. enamel. Cu wire or better = 5x0.4mm or what you have. It just affects the efficiency, more or less. The overall dimensions of this prototype are 15cm x 10cm x 3cm, so it = is quite compact and since it runs from a 12V battery you can use it for = /p tests. Also you can of course use more than 2 power steps by using a = multi step switch and more taps. A DDS signal generator with rectangular wave form or a sine signal = coming from a HF TX may be used. The waveform doesn't matter as long as = the peak input voltage exceeds 5 Vp. 73, Stefan/DK7FC PS: Yes, it is nothing new and someone has done it before! Am 28.06.2012 11:46, schrieb M0FMT:=20 Hi again Stefan The Litz is too, only by the Km or 10Kg reel.......... :@(( Do you create your own I have 0.125 solid C/E guess that could be = stranded up to make a synth? =20 73 es GL Pete M0FMT IO91UX From: M0FMT mailto:m0fmt@yahoo.co.uk To: mailto:rsgb_lf_group@blacksheep.org = mailto:rsgb_lf_group@blacksheep.org=20 Sent: Thursday, 28 June 2012, 10:22 Subject: Re: LF: Re: RE: 472 kHz PA running at 12 VDC Hi Stefan = http://www.ebay.co.uk/itm/IRFZ24N-Transistor-x-1-pieces-IRFZ24-/160818253= 496?pt=3DUK_BOI_Electrical_Components_Supplies_ET&hash=3Ditem257183ceb8 Just over =C2=A35 a pop! = http://www.ebay.co.uk/itm/NEW-ICL7667CPA-MAXIM-IC-DRIVER-MOSFET-DUAL-PWR-= 8-DIP-1-PIECE-B7-/160779362423?pt=3DLH_DefaultDomain_0&hash=3Ditem256f326= 077 Just over =C2=A36 a pop! But what is the =E2=80=9CUnobtainium=E2=80=9D ferrite? = =E2=80=A6=E2=80=A6 ;0) Chees Pete FMT From: Jean-Pierre M=C3=A9r=C3=A9 mailto:jpm.f1afj@online.fr To: rsgb_lf_group@blacksheep.org=20 Sent: Thursday, 28 June 2012, 9:42 Subject: Re: LF: Re: RE: 472 kHz PA running at 12 VDC Hello Stephan , Me too=20 73 , Jean-Pierre F1AFJ =20 Le 28/06/2012 10:36, M0FMT a =C3=A9crit : Hi Stephan Me Too 73 es GL Pete M0FMT IO91UX From: "PA1SDB, Peter" mailto:pa1sdb@amsat.org To: rsgb_lf_group@blacksheep.org=20 Sent: Thursday, 28 June 2012, 9:12 Subject: LF: Re: RE: 472 kHz PA running at 12 VDC like ----- Original Message -----=20 From: Rik Strobbe=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Thursday, June 28, 2012 6:35 AM Subject: LF: RE: 472 kHz PA running at 12 VDC If someone is interested i may convert the circuit from my mind = into a schematic as a png file. Always interested ;-) 73, Rik ON7YD - OR7T ------=_NextPart_000_0047_01CD55F8.1E393B50 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable =EF=BB=BF
Pete
I find for a class E PA or class C with series = resonant=20 cct at frequency of interest you do not need a LPF.
To resonate the PA use an Air core inductor and = fixed=20 capicator ie for 500 Khz use 5nF in series with 20uH inductor. Adjust = inductor=20 slightly up/down in value to resonate at exact freq of interest. Use an = old LOPT=20 core 8 turns Prim 24 turns Sec. The wire does not have to be Litz. Prim = 2.5mm=20 elec wire and Sec 1mm. I have used both litz and elec wire and find no=20 difference.
A couple of hours should build this type of=20 TX
 
g3kev
 
 
----- Original Message -----
From:=20 M0FMT
Sent: Friday, June 29, 2012 = 11:31=20 AM
Subject: Re: LF: Re: RE: 472 = kHz PA=20 running at 12 VDC

Hi Rik
 
Many thanks for your very useful information. I hope others = find=20 this as well.
Yes I said in an earlier mail what the PA and driver would = cost=20 from E-bay (my supplier of choice... :o)) but at least they are=20 obtainable.
 
The current hold are the Ferrites or the Iron Dust = toriods.=20 This is the usual problem because one black iron ring looks very much = like=20 another. Once you have it in your hands you can do a test. What I do = is to put=20 a few turns on an unknown core and measure the inductance then compare = the=20 results with the theoretical value obtained from a range of cores with = the=20 same dimensions using "Mini Core" SW. At the moment I have a = source for the T1 core but not the choke. And = surprisingly=20 I can't find the T80-2s they were every where once upon a time. Anyway = I do=20 have a variety of cores that will probably do for the O/P filtre. = One day=20 I will find a design I  can kit perfectly.
 
I like your transverter, I am getting torn between projects = right=20 now. Q6 / Q7 driver as you say can be reproduced for each FET gate = cheaply in=20 fact I have the parts!
 
I will now crawl into my cave and start to build. Thanks to you = and=20 Stefan.
 
73 es GL Pete M0FMT IO91UX
From: Rik=20 Strobbe <Rik.Strobbe@fys.kuleuven.be>
To: = "rsgb_lf_group@blacksheep.org"=20 <rsgb_lf_group@blacksheep.org>
Sent: Friday, 29 June 2012,=20 8:49
Subject: RE: = LF: Re: RE:=20 472 kHz PA running at 12 VDC
 

Hello Pete,
 
I assume that the more exotic parts are the = power FET (IRFZ48N) and the driver IC=20 (ICL7667).
The IRFZ48N = is a 55V / 64A / 0.014 Ohm=20 device. For a first try you could replace it by far = more common IRF460 that = is 100V / 28A / 0.06=20 Ohm.
A bit of reverse=20 engineering: Stefan states 50W output at 80% efficiency =3D 62.5W input =3D 5.2A at 12V.
So with = a 28A device you are on the = safe side.
The larger = Ron (0.06=20 Ohm vs 0.014 Ohm) will (in theory) reduce the efficiency. But 5.2A in 0.014 = Ohm=20 is only about 0.4W loss = (for a IRFZ48N). For = a IRF460 it = is 5.2A in 0.06 Ohm =3D 1.6W=20 loss.
So the losses (12.5W) are probably=20 more due to the non = perfect switching than due to the Ron of the FETs.
An alternative for the ICL7667 is=20 a TC4426 or=20 a homebrew driver (see http://www.pa3bca.nl/images/stories/500KHz/500khz_transver= ter_full.gif/images/stories/500KHz/500khz_transverter_full.gif).
 
73, Rik  ON7YD -=20 OR7T
 
Van: = owner-rsgb_lf_group@blacksheep.org=20 [owner-rsgb_lf_group@blacksheep.org] namens M0FMT=20 [m0fmt@yahoo.co.uk]
Verzonden: donderdag 28 juni 2012=20 20:41
Aan: rsgb_lf_group@blacksheep.org
Onderwerp: = Re: LF:=20 Re: RE: 472 kHz PA running at 12 VDC

Hi Stefan
 
I like this and would like to make to make = it. I so=20 far have tracked down most bits but as usual the Unobtainium of so many construction = projects=20 that fall at the last hurdle unless they are Kits........ no chance of = that I=20 suppose?
 
There will be those who tell me its easy to = get the=20 bits but unless you work for a company that uses this stuff it = can not be=20 slipped through the "Purchasing" it becomes a positive stop!!=20
Like the Litz I just put that in one of our = big=20 outfits with min orders and it said it had over one hundred thousand = Litz and = promptly=20 collapsed. But = they have=20 one of the toroids (T1) wow and its not a min = order=20 either double wow! Litz can be fabricated from 0.125=20 Cu/En?  Hmm=20 it's plaited ?
Wima caps are available from Maplin = haven't checked=20 in depth but they usually are.
 
I like the idea of using a DDS or Transceiver as a = master osc = source div. by=20 four.
 
Generally I buy my power FETs by = the hand full=20 off E-bay they may not be ideal but are cheap!! 50P (eer = 60Ec) = (Never mind the=20 quality but feel the width... principle) and the drivers TC range = for=20 slightly more.
 
I'll keep searching for a bit but if anyone has a = kitting=20 list (UK source) may be they could publish it? 
 
And thanks Stefan nothing under the Sun is "New" = but in=20 context it is new and worth while thanks!
73 es GL Pete M0FMT IO91UX
 =20
From: Stefan Sch=C3=A4fer=20 <Stefan.Schaefer@iup.uni-heidelberg.de>
To: = rsgb_lf_group@blacksheep.org=20
Sent: Thursday, 28 = June=20 2012, 16:53
Subject: Re: LF:=20 Re: RE: 472 kHz PA running at 12 VDC

Hi MF,=20

Late at night, i made draw the schematic. Here it is: https://dl.dropbox.com/u/19882028/MF/100W%20475kHz%20PA.pn= g =20 (picture of prototype https://dl.dropbox.com/u/19882028/MF/DK7FC%20472%20kHz%20P= A%2015W%2B100W.JPG)

Most=20 of the parts are not critical.

The ferrite cores are the blue = EPCOS = types, N30=20 material. Details are in the image. But you may use a FT140-77 = alternatively=20 and double the primary and secondary number of turns.

There are = many=20 alternatives, also to the FETs. Instead of the IRZF48N = you may try a=20 IRF1405. This=20 one has a lower on-resistance but a higher input capacity. Maybe it = works even=20 better, i didn't try to many parts. Switching times are not critical. = So you=20 need to find a compromise between low on resistance and input capacity = while=20 the Drain-Source voltage should be 55V for a 12V = supply.

Instead of RF=20 litz wire (i=20 use this one: http://www.reichelt.de/index.html?ACTION=3D3;ARTICLE=3D572= 06;SEARCH=3DCLI%20200%2F30=20 ) you can also use 1mm diam. enamel. Cu wire or better 5x0.4mm or what = you=20 have. It just affects the efficiency, more or less.

The overall = dimensions of this prototype are 15cm x 10cm x 3cm, so it is quite = compact and=20 since it runs from a 12V battery you can use it for /p tests. Also you = can of=20 course use more than 2 power steps by using a multi step switch and more = taps.

A=20 DDS signal generator with rectangular wave form or a sine signal = coming from a=20 HF TX may be used. The waveform doesn't matter as long as the peak = input=20 voltage exceeds 5 Vp.

73, Stefan/DK7FC

PS: Yes, it=20 is nothing new and someone has done it = before!






Am=20 28.06.2012 11:46, schrieb M0FMT:=20
Hi again Stefan
 
The Litz is too, only by the Km or = 10Kg=20 reel.......... :@((
 
Do you create your own I have 0.125 solid C/E guess that could = be=20 stranded up to make a synth?

 
73 es GL=20 Pete M0FMT IO91UX
From: M0FMT mailto:m0fmt@yahoo.co.uk
<= SPAN=20 style=3D"FONT-WEIGHT: bold">To: mailto:rsgb_lf_group@blac= ksheep.org=20 mailto:rsgb_lf_group@blac= ksheep.org=20
Sent: Thursday, = 28 June=20 2012, 10:22
Subject: Re:=20 LF: Re: RE: 472 kHz PA running at 12 VDC

Hi Stefan
http://www.ebay.co.uk/itm/IRFZ24N-Transistor-x-1-pieces-IRFZ24-/= 160818253496?pt=3DUK_BOI_Electrical_Components_Supplies_ET&hash=3Dite= m257183ceb8
Just over =C2=A35 a pop!
http://www.ebay.co.uk/itm/NEW-ICL7667CPA-MAXIM-IC-DRIVER-MOSFET-= DUAL-PWR-8-DIP-1-PIECE-B7-/160779362423?pt=3DLH_DefaultDomain_0&hash=3D= item256f326077
Just over =C2=A36 a pop!
But what is the =E2=80=9CUnobtainium=E2=80=9D = ferrite?  =20 =E2=80=A6=E2=80=A6 ;0)
Chees Pete = FMT
   From: Jean-Pierre = M=C3=A9r=C3=A9 mailto:jpm.f1afj@online.fr
= To: rsgb_lf_group@blacksheep.= org=20
Sent: Thursday, = 28 June=20 2012, 9:42
Subject: Re: LF:=20 Re: RE: 472 kHz PA running at 12 VDC

Hello Stephan ,
Me too
73  , Jean-Pierre = F1AFJ =20



Le 28/06/2012 10:36, M0FMT = a=20 =C3=A9crit :
Hi Stephan
 
Me Too

73 es GL Pete M0FMT IO91UX
From: "PA1SDB, Peter" mailto:pa1sdb@amsat.org
To: rsgb_lf_group@blacksheep.= org=20
Sent: = Thursday, 28 June=20 2012, 9:12
Subject: LF:=20 Re: RE: 472 kHz PA running at 12 VDC

like
 
-----=20 Original Message -----
From:=20 Rik Strobbe =
To:=20 rsgb_lf_group@blacksheep.= org=20
Sent:=20 Thursday, June 28, 2012 6:35 AM
Subject:=20 LF: RE: 472 kHz PA running at 12 VDC

If someone = is interested=20 i may convert the=20 circuit from my mind into a schematic as = a png=20 file.
 
Always interested = ;-)
 
73, Rik  ON7YD -=20 = OR7T






<= /DIV>





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