20090102.ba v04_n235.bam.20090102 >From ???@??? Fri Jan 2 17:11:09 2009 -0600 Date: Fri, 2 Jan 2009 17:10:29 CST From: Old Tube Radios To: Old Tube Radios Subject: BOATANCHORS digest 4235 Message-Id: <20090102231032.43F3E10B0A3@srvr1.theporch.com> BOATANCHORS Digest 4235 Topics covered in this issue include: 1) Re: Galaxy Calibrator by Mike Steussy 2) New Material Posted- Cdn Marconi XG54 Series Receivers by Jerry Proc 3) Re: CHU Move by "Don Davis" 4) Re: CHU Move by "Arden Allen" 5) RE: CHU Move by "Ed Sieb" 6) RE: CHU Move by RICHARD SOLOMON 7) RE: CHU Move by Jerry Proc 8) Re: Insulated Gate Bipolar Transistors by "David Stinson" 9) Re: Insulated Gate Bipolar Transistors by "David Stinson" 10) Re: Insulated Gate Bipolar Transistors by "David Stinson" 11) Re: Insulated Gate Bipolar Transistors by "David Stinson" 12) Re: Insulated Gate Bipolar Transistors by "David Stinson" 13) 6146 Tubes by W9MWS@aol.com 14) Re: Insulated Gate Bipolar Transistors by "Arden Allen" 15) Re: CHU Move by "Arden Allen" 16) Re: Isolated Gate Bipolar Transistors by "Arden Allen" 17) Fw: Jan 2009 QST Article on ARC-5's by "JAMES HANLON" 18) RE: CHU Move by Scott Robinson 19) FS, a few Old Timers Bulletin back issues by john 20) Re: Insulated Gate Bipolar Transistors by "Arden Allen" ---------------------------------------------------------------------- Message-ID: <495D1714.9020905@cox.net> Date: Thu, 01 Jan 2009 14:18:44 -0500 From: Mike Steussy MIME-Version: 1.0 To: Old Tube Radios Subject: Re: Galaxy Calibrator Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit Bob, my Galaxy V came with a Knight kit calibrator nicely installed on the lid’s underside with black painted screws. Plugs into the octal socket and works FB. I like WA5JCI’s idea of building one from the schematic. I did that for my NCX-3. 73 es HNY! // Mike Steussy AE4R ------------------------------ Date: Thu, 1 Jan 2009 12:03:31 -0800 (PST) From: Jerry Proc Subject: New Material Posted- Cdn Marconi XG54 Series Receivers To: Old Tube Radios MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Message-ID: <523373.37810.qm@web90605.mail.mud.yahoo.com> Hello Everyone, I have posted a new document on the Canadian Marconi XG54 and XG54G series of single frequency receivers. http://www.jproc.ca/marconi/xg54.html I found this receiver type on the web quite accidently while searching around for something entirely different. Another item found for the virtual museum. -- Regards, Jerry Proc E-mail: jerry7proc@yahoo.com __________________________________________________________________ Be smarter than spam. See how smart SpamGuard is at giving junk email the boot with the All-new Yahoo! Mail. Click on Options in Mail and switch to New Mail today or register for free at http://mail.yahoo.ca ------------------------------ Message-ID: <79CF948D800B4570AF4F619F738242AE@hppav> From: "Don Davis" To: Old Tube Radios Cc: "Jerry Proc" Subject: Re: CHU Move Date: Thu, 1 Jan 2009 01:10:13 -0800 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit Why? ----- Original Message ----- From: To: "Old Tube Radios" Cc: "Jerry Proc" Sent: Wednesday, December 31, 2008 5:16 PM Subject: Re: CHU Move > CHU move- 7850kc, now theres a real dumb place to put it. > > ------------------------------ Message-ID: <000701c96c54$d6d1b4d0$1f9e480c@KB6NAX> From: "Arden Allen" To: Old Tube Radios Subject: Re: CHU Move Date: Thu, 1 Jan 2009 13:06:31 -0800 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit > Why? Cuz it's outside the band limits for our vintage ham banders |:-( Let's all build 7850kHz single frequency CHU monitors! Go cheap and build a converter for that unused AC/DC radio. Better yet, just convert the AC/DCer to a CHU receiver. Heat up the irons, chaps! Arden Allen KB6NAX ------------------------------ From: "Ed Sieb" To: Old Tube Radios Subject: RE: CHU Move Date: Thu, 1 Jan 2009 16:22:53 -0500 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit I can receive it fine on any number of my receivers - my 51J4, SP600, AR88, even my Trio 9R59 (Lafayette HE30). OK - so I can't recieve it on my HQ170, or my NC303. Oh well. Ed, VA3ES --------------------------------------------------------------------------- Arden Allen wrote: Cuz it's outside the band limits for our vintage ham banders |:-( Let's all build 7850kHz single frequency CHU monitors! Go cheap and build a converter for that unused AC/DC radio. Better yet, just convert the AC/DCer to a CHU receiver. Heat up the irons, chaps! Arden Allen KB6NAX ------------------------------ Message-ID: Content-Type: multipart/alternative; boundary="_82e95a0a-0310-4a0c-afed-fe2968e07bce_" From: RICHARD SOLOMON To: Old Tube Radios Subject: RE: CHU Move Date: Thu, 1 Jan 2009 22:54:47 +0000 MIME-Version: 1.0 --_82e95a0a-0310-4a0c-afed-fe2968e07bce_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable File under ..."you can't please all the folks=2C etc"... This is the B/A Reflector=2C so get an old ARC-5 Receiver and dedicate it to CHU. =20 73=2C Dick=2C W1KSZ> From: gumbear@pacbell.net> To: boatanchors@theporch.co= m> Subject: Re: CHU Move> Date: Thu=2C 1 Jan 2009 13:06:31 -0800> > > Why?>= > Cuz it's outside the band limits for our vintage ham banders |:-(> > Let= 's all build 7850kHz single frequency CHU monitors! Go cheap and build a> c= onverter for that unused AC/DC radio. Better yet=2C just convert the AC/DCe= r> to a CHU receiver. Heat up the irons=2C chaps!> > Arden Allen> KB6NAX> = --_82e95a0a-0310-4a0c-afed-fe2968e07bce_ Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ---REMAINDER OF MESSAGE TRUNCATED--- * * This post contains a forbidden message format * * (such as an attached file, a v-card, HTML formatting) * * Mail Lists at theporch.com only accept PLAIN TEXT * * If your postings display this message your mail program * * is not set to send PLAIN TEXT ONLY and needs adjusting * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * --_82e95a0a-0310-4a0c-afed-fe2968e07bce_-- ------------------------------ Date: Thu, 1 Jan 2009 19:42:42 -0800 (PST) From: Jerry Proc Subject: RE: CHU Move To: Old Tube Radios MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Message-ID: <456204.47918.qm@web90605.mail.mud.yahoo.com> Hello Everyone, Guess we have been spoiled by having CHU at 7.335 all these years since most of the ham band only receivers cannot pick up WWV. It seems to me that if all you are doing is setting your wristwatch for the correct time, why not try going to NIST for the offical time? http://nist.time.gov/ If my computer is on I can obtain the time faster than waiting 30 seconds for the filaments to warm up in a general coverage vacuum tube receiver. Nostalgia for things that glow has its place but computers are definitely better at serving us for other functions :-) -- Regards, Jerry Proc E-mail: jerry7proc@yahoo.com --- On Thu, 1/1/09, Ed Sieb wrote: > From: Ed Sieb > Subject: RE: CHU Move > To: "Old Tube Radios" > Received: Thursday, January 1, 2009, 1:22 PM > I can receive it fine on any number of my receivers - my > 51J4, SP600, AR88, > even my Trio 9R59 (Lafayette HE30). OK - so I can't > recieve it on my HQ170, > or my NC303. Oh well. > > Ed, VA3ES > --------------------------------------------------------------------------- > > Arden Allen wrote: > Cuz it's outside the band limits for our vintage ham > banders |:-( > Let's all build 7850kHz single frequency CHU monitors! > Go cheap and build a > converter for that unused AC/DC radio. Better yet, just > convert the AC/DCer > to a CHU receiver. Heat up the irons, chaps! > Arden Allen > KB6NAX __________________________________________________________________ Instant Messaging, free SMS, sharing photos and more... Try the new Yahoo! Canada Messenger at http://ca.beta.messenger.yahoo.com/ ------------------------------ Message-ID: From: "David Stinson" To: Old Tube Radios Subject: Re: Insulated Gate Bipolar Transistors Date: Thu, 1 Jan 2009 23:42:51 -0600 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=response Content-Transfer-Encoding: 7bit In case anyone was interested- Time for me to risk showing my considerable "ig-nurn-ss" again. I did some research on using the Insulated Gate Bipolar Transistor (IGBT) devices as a "Borg Implant" to plate modulate a high-power AM transmitter, for us "po-folks" who can't afford hundreds of bucks for a kilowatt transformer. I got the spec sheet on a tiny little device- http://www.supertex.com/pdf/datasheets/GN2470.pdf a Supertex GN2470- that can do 3.5 amps, CE breakdown 700 volts. There are "hefty-er" ones out there, but this will do for discussion. It has a low on-state voltage drop, so probably won't even need heat sinking at our low currents. And did I mention it's tiny? This little booger is a quarter of an inch square and a tenth of an inch thick. Now, I'm not the brightest candle on the cake- I just barely get by. But I think I understand what I'm looking at and hope you brighter lights can comment, and tell me where I'm wrong (or right). I promise you won't hurt my feelings ;-). I'm not addressing the audio filtering requirements yet- just the operating points. The Transfer Characteristics curve looks a lot like that for a triode with -grid bias, and only has a small amount of "bow" at the bottom near cut-off. I'm going to use some figures that are "above legal limit," but it's only for illustration to see just how full of "hooo-weee" I am. Let's say I want my big final to run, at full carrier, 2000 volts at 1 amp. I series eight or ten of these for a large breakdown margin and hook all the gates together. I can get away with that because the input capacitance of one of these is about 100 pFd, vs 2700 pFd for an IRF450 MOSFET; I think .03 mFds across my audio chain would make for some "bass-ee" audio ;-). I bias the things "full on" at 6 volts or more for tune-up, then back the bias down to 4.5 volts, lowering the current to about 400 mils on transmit with no modulation. Drive the audio to it about 2 V PTP, and the current swings from near cut-off, up to 1 amp at about 6 volts. The slight bow at the low end introduces some asymmetry, but doesn't look too bad, considering. This device takes more drive than the power MOSFET; about 2 V PTP for the swing I want vs. half a volt for something like the IRF450, and the curve is straighter and steeper for the MOSFET, but this is actually a "plus" on the side of the IGBT, because getting the bias exactly right on the MOSFET and keeping it there when you've only got a half a volt to play with is pretty tough. And getting a couple of volts drive to the IGBT thing is easy- the output of any old audio amp with a few watts "umph" should do nicely. What do you smart guys think? 73 D.S. ------------------------------ Message-ID: <4B1730D0FE4746E5872221D45D08528B@boudreaux> From: "David Stinson" To: Old Tube Radios Subject: Re: Insulated Gate Bipolar Transistors Date: Fri, 2 Jan 2009 01:36:21 -0600 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=response Content-Transfer-Encoding: 7bit Someone smarter than me said: >> 2000 volts at 1 amp. I series eight or ten of these for a large >> breakdown margin and hook all the gates together. >Won't you exceed the gate-emitter rating doing that? Each of the ten IGBTs >will have about 200 volts across it in a ladder. Doesn't that mean each >gate (grid) needs to be 200 volts up a ladder as well? DOH! (slapping forehead). ------------------------------ Message-ID: <4C224455E08D48CCA224275DAAF28BBE@boudreaux> From: "David Stinson" To: Old Tube Radios Subject: Re: Insulated Gate Bipolar Transistors Date: Fri, 2 Jan 2009 01:52:46 -0600 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=response Content-Transfer-Encoding: 7bit How about this: Instead of putting a chain of them in the B+ lead, how about one heavy duty one in the cathode DC return path? The gate would then be referenced to ground and you'd still get the current control to make it work. Imagine- a big 4-1000 tube, modulated by that little thing ;-) ------------------------------ Message-ID: <346EEF234000482C8261754F04A36C58@boudreaux> From: "David Stinson" To: Old Tube Radios Subject: Re: Insulated Gate Bipolar Transistors Date: Fri, 2 Jan 2009 07:49:04 -0600 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=response Content-Transfer-Encoding: 7bit Well, now hold on a sec.... The whole idea of these is that the Gate circuit is extremely hi-Z relative to the Collector/Emitter circuit. In the "ideal" device, the two circuits are completely isolated from each other. All of the Gates go to a pull-down resistor to ground. According to the specs, with the gate swinging it's absolute maximum of +/- 20 volts, the leakage current to the C/E circuit is about 100 nanoamps- pretty tiny. So if my pull-down is, say, a few K ohms, we've got a voltage divider of a few bizillion ohms C/E to G, with an itty-bitty fraction from G to ground, so even if the compound device should see the whole B+ at zero mod, it should never develop more than a few volts G to ground. I'd probably have to drive it harder, but that's no problem. I'm going to build a three-step device and do some DC measurements.... not ready to give up just yet ;-). 73 Dave S. ------------------------------ Message-ID: From: "David Stinson" To: Old Tube Radios Subject: Re: Insulated Gate Bipolar Transistors Date: Fri, 2 Jan 2009 08:01:34 -0600 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=response Content-Transfer-Encoding: 7bit > the compound device should see the whole B+ at zero mod, Duh! I mean full mod.... or.... ummm... Blast it...You know! ------------------------------ From: W9MWS@aol.com Message-ID: Date: Fri, 2 Jan 2009 09:21:17 EST Subject: 6146 Tubes To: Old Tube Radios MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1230906077" -------------------------------1230906077 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit 1 Selectron 6146B tube in JAN box ... used, tested good. $10 plus shipping 1 RCA 6146B tube in white box ... used, tested good. $10 plus shipping 1 RCA 6146 tube no box ... used, slightly loose at the base, tested OK. $5 plus shipping All three tubes for $20 plus $5 postage. Please contact me off list at n9qr at n9qr dot com or w9mws at arrl dot net Thank, 73 and Happy New Year 2009 Mike N9QR -------------------------------1230906077 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ---REMAINDER OF MESSAGE TRUNCATED--- * * This post contains a forbidden message format * * (such as an attached file, a v-card, HTML formatting) * * Mail Lists at theporch.com only accept PLAIN TEXT * * If your postings display this message your mail program * * is not set to send PLAIN TEXT ONLY and needs adjusting * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * -------------------------------1230906077-- ------------------------------ Message-ID: <002601c96cff$b70099e0$049e480c@KB6NAX> From: "Arden Allen" To: Old Tube Radios Subject: Re: Insulated Gate Bipolar Transistors Date: Fri, 2 Jan 2009 09:29:40 -0800 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit David, The two items you have not apparently tackled yet are *drain dissipation* and drive requirements. Drain dissipation is going to be the factor that decides how much you can get out of the thing. In the real solid state world multple lower power amps are fed into a combiner to get the power up to where it's wanted. Your little quarter inch device may do very well running legal limit in the citizens band (ouch!). That's if it can actually still produce reasonable power output at 27MHz. Why are you talking about "gates"? The input to the device is a *base*, the thing you find in bipolar transistors. Think "impedances, impedances, impedances....." You might get started in the right direction by studying class D amplfiers: http://users.ece.gatech.edu/~mleach/ece4435/f01/ClassD2.pdf Arden Allen KB6NAX ------------------------------ Message-ID: <002501c96cff$b5cbea70$049e480c@KB6NAX> From: "Arden Allen" To: Old Tube Radios Subject: Re: CHU Move Date: Fri, 2 Jan 2009 09:05:01 -0800 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit > If my computer is on I can obtain the time faster than waiting 30 seconds for the filaments to warm up in a general coverage vacuum tube receiver. Yeah, but how long does it take for the internet "filaments" to warm up? At least you know WWV or CHU time is accurate to within a second. If your wrist watch or station clock is cheating you the internet will just add to the confusion. (I always though they should have named it NITS ;-) Arden Allen KB6NAX ------------------------------ Message-ID: <006d01c96d01$63cd17b0$049e480c@KB6NAX> From: "Arden Allen" To: Old Tube Radios Subject: Re: Isolated Gate Bipolar Transistors Date: Fri, 2 Jan 2009 09:41:44 -0800 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit > Anyone familiar with the new Isolated Gate Bipolar Transistors (IGBT)? Somewhat, having worked on some switchmode power stuff before retiring. The advantage of the IGBT is the combination of low drive impedance via the bipolar transistor and low switching loss of the MOSFET, a very efficient combination. However the danger in trying to make these devices work in linear circuits is akin to doing the same thing with switching MOSFETS, poor characterization of linear drive requirements. The best approach would be to come up with a pulsewidth modulation scheme to excite your final tank, just like the big boys do nowadays. Linear is fast becoming a thing of the past in power. And then you gotta build an efficient output filter to clean up the harmonics. Gooooooood luck ;-) Happy new year to all you fine listers and especially to our jailkeeper in charge, Jack. Arden Allen KB6NAX ------------------------------ Message-ID: From: "JAMES HANLON" To: Old Tube Radios Cc: Subject: Fw: Jan 2009 QST Article on ARC-5's Date: Fri, 2 Jan 2009 11:54:26 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_00A2_01C96CD0.DCCCDAA0" This is a multi-part message in MIME format. ------=_NextPart_000_00A2_01C96CD0.DCCCDAA0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Y'all, As you can see from the string below, Don, W7WLL, is looking for some = help in identifying a piece of WW2 military gear for which he has only a = schematic. Can anyone help? Please contact Don at = w7wll@arrl.net . Thanks, Jim, W8KGI ----- Original Message -----=20 From: Don Tucker=20 To: JAMES HANLON=20 Sent: Friday, January 02, 2009 11:41 AM Subject: Re: Jan 2009 QST Article on ARC-5's That would be most helpful Jim. I've queried several of the locals who = are as old as I or have an interest in old mil equipment but none have = been able to help. The schematic is two sided and on one side the autotune network is shown = as hatched out, which leads to the obvious conclusion that there were = two versions of the unit. Any help appreciated. Don W7WLL ----- Original Message -----=20 From: JAMES HANLON=20 To: Don Tucker=20 Sent: Friday, January 02, 2009 9:34 AM Subject: Re: Jan 2009 QST Article on ARC-5's Don, I'm sorry for not replying earlier. Your message wound up in my Junk = Mail folder and I just now found it when I was cleaning the folder out. I don't recognize this particular piece of equipment. With your = permission I will forward your message to the "Boatanchors" reflector. = Perhaps someone there will know what it is or will forward it to one of = the Military Equipment reflectors. Jim, W8KGI ----- Original Message -----=20 From: Don Tucker=20 To: w8kgi@arrl.net=20 Sent: Tuesday, December 23, 2008 12:29 PM Subject: Jan 2009 QST Article on ARC-5's Boy did that bring back memories from my early '50's ham radio days. = Had=20 those, a BC-610 and some other old stuff. Still have a set of = ARC-5's buried=20 someplace and am getting ready to attack a pristine R-390A by = Collins. A question. Amongst all the ham junk (excuse me,things) collected = over the=20 last 50 years plus, I have a WWII era schematic that I've never been = able to=20 connect to a rig (nomenclature). There is no reference on the = schematic,=20 just the schematic itself. I'm trying to figure out what it is of = and=20 wonder if you can help? Power came from a D-601 dynamotor. (I used to use the PE-103 = dynamotor in my=20 old AM mobile). The tube lineup is a 12SG7 RF amp, 12SG7 mixer, 12SG7 Ist IF, the = same for=20 the 2nd IF, 12H6 limiter, 12SL7 each for the driver and detector = and AVC,=20 12SJ7 local osc, 12A6 audio output, 12SJ7 HF osc, and 12SG7 = multiplier=20 with two 12SJ7's in what is labeled a CFI Unit. It appears to have = 8=20 channels and an autotune control unit in one configuration and none = in=20 another. I can supply a copy of both sides of the schematic if you think you = could=20 help me track this down. Don W7WLL=20 ------=_NextPart_000_00A2_01C96CD0.DCCCDAA0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ---REMAINDER OF MESSAGE TRUNCATED--- * * This post contains a forbidden message format * * (such as an attached file, a v-card, HTML formatting) * * Mail Lists at theporch.com only accept PLAIN TEXT * * If your postings display this message your mail program * * is not set to send PLAIN TEXT ONLY and needs adjusting * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ------=_NextPart_000_00A2_01C96CD0.DCCCDAA0-- ------------------------------ Mime-Version: 1.0 Message-Id: Date: Fri, 2 Jan 2009 12:57:27 -0800 To: Old Tube Radios From: Scott Robinson Subject: RE: CHU Move Content-Type: text/plain; charset="us-ascii" ; format="flowed" >HI Jerry, Ah, but the stated tolerance on the site when I accessed it was +/- 15 seconds. I like prop time from Colorado to California much better, about 1000/186000 of a second. Peace, Scott >Hello Everyone, > >Guess we have been spoiled by having CHU at 7.335 all these years >since most of the ham band only receivers cannot pick up WWV. > >It seems to me that if all you are doing is setting your wristwatch >for the correct time, why not try going to NIST for the offical >time? http://nist.time.gov/ > >If my computer is on I can obtain the time faster than waiting 30 >seconds for the filaments to warm up in a general coverage vacuum >tube receiver. >Nostalgia for things that glow has its place but computers are >definitely better at serving us for other functions :-) > > ------------------------------ Message-Id: <6.2.1.2.2.20090102172356.0398bae0@pop-server.nc.rr.com> Date: Fri, 02 Jan 2009 17:27:44 -0500 To: Old Tube Radios From: john Subject: FS, a few Old Timers Bulletin back issues Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; format=flowed I have the following pack of duplicates available Vol 34 Feb May Aug Nov Vol 35 Feb Vol 37 May Vol 38 Feb 7 issues for $12 plus 2$ ship in US. Paypal preferred John ------------------------------ Message-ID: <002d01c96d2f$63cab7d0$7b9d480c@KB6NAX> From: "Arden Allen" To: Old Tube Radios Subject: Re: Insulated Gate Bipolar Transistors Date: Fri, 2 Jan 2009 14:55:01 -0800 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit OH, my red face! Alzheimers has taken it's toll. I got it all backwards. The MOSFET gate is at the input, the bipolar is what handles the current. Been a while since I worked on this stuff and IGBT's passed me by rather quickly. Most of what I worked on were bipolars driving MOSFETS. Belay all that rubbish I posted :-( Arden Allen KB6NAX ....... > David, > > The two items you have not apparently tackled yet are *drain dissipation* > and drive requirements. Drain dissipation is going to be the factor that > decides how much you can get out of the thing. In the real solid state > world multple lower power amps are fed into a combiner to get the power up > to where it's wanted. Your little quarter inch device may do very well > running legal limit in the citizens band (ouch!). That's if it can actually > still produce reasonable power output at 27MHz. Why are you talking about > "gates"? The input to the device is a *base*, the thing you find in bipolar > transistors. Think "impedances, impedances, impedances....." You might get > started in the right direction by studying class D amplfiers: > > http://users.ece.gatech.edu/~mleach/ece4435/f01/ClassD2.pdf > > Arden Allen > KB6NAX > ------------------------------ End of BOATANCHORS Digest 4235 ******************************