But Class E transmitters don't glow in the dark. You have to put Xmas lights in them. Parts are not that difficult to find if you're willing to spend the time to find them. To me, Class E (asy) lacks the traditional nostalgia that many of us feel in a tube-based transmitter. As someone already pointed out, there are lots of great circuits in the older ARRL Handbooks, Radio and Engineers' Handbook, etc. The ARRL has a new book just out called "RF Amplifier Classics" and includes two-dozen projects and articles from the pages of QST and QEX, published between 1980 and 2003. There are amps for HF, MF, VHF and microwave. Pete, wa2cwa
On Tue, 28 Sep 2004 19:10:27 -0400 Neal Newman <[EMAIL PROTECTED]> writes: > Build a Class E transmitter. > Parts for building a tube transmitter is getting harder to find > everyday... > > [EMAIL PROTECTED] wrote: > > >Hello All: > > > >I'd like to build my own AM transmitter. > >Tube style; more than 200 watts. > > > >Sure a heck of a lot to choose from...but I'd like to hear what you > think. > > > > > >OR...if someone knows of a home brew for sale.... > > > >Tnx, > >Steve > >WA2TAK From [EMAIL PROTECTED] Wed Sep 29 08:36:52 2004 Return-Path: <[EMAIL PROTECTED]> Delivered-To: [email protected] Received: from pmesmtp03.mci.com (unknown [199.249.20.32]) by mailman.qth.net (Postfix) with ESMTP id E8990859BFD for <[email protected]>; Wed, 29 Sep 2004 08:36:35 -0400 (EDT) Received: from pmismtp05.wcomnet.com ([166.38.62.53]) by firewall.mci.com (Iplanet MTA 5.2) with ESMTP id <[EMAIL PROTECTED]> for [email protected]; Wed, 29 Sep 2004 12:29:11 +0000 (GMT) Received: from pmismtp05.wcomnet.com by pmismtp05.mcilink.com (iPlanet Messaging Server 5.2 HotFix 1.14 (built Mar 18 2003)) with SMTP id <[EMAIL PROTECTED]> for [email protected]; Wed, 29 Sep 2004 12:29:11 +0000 (GMT) Received: from XS118V2451242A ([166.32.178.164]) by pmismtp05.mcilink.com (iPlanet Messaging Server 5.2 HotFix 1.14 (built Mar 18 2003)) with ESMTP id <[EMAIL PROTECTED]> for [email protected]; Wed, 29 Sep 2004 12:29:11 +0000 (GMT) Date: Wed, 29 Sep 2004 08:29:10 -0400 From: Brett gazdzinski <[EMAIL PROTECTED]> Subject: RE: [AMRadio] Home Brew In-reply-to: <[EMAIL PROTECTED]> To: 'Discussion of AM Radio' <[email protected]> Message-id: <[EMAIL PROTECTED]> MIME-version: 1.0 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1441 X-Mailer: Microsoft Outlook, Build 10.0.4510 Content-type: text/plain; charset=us-ascii Content-transfer-encoding: quoted-printable Importance: Normal X-Priority: 3 (Normal) X-MSMail-priority: Normal X-BeenThere: [email protected] X-Mailman-Version: 2.1.4 Precedence: list Reply-To: Discussion of AM Radio <[email protected]> List-Id: Discussion of AM Radio <amradio.mailman.qth.net> List-Unsubscribe: <http://mailman.qth.net/mailman/listinfo/amradio>, <mailto:[EMAIL PROTECTED]> List-Archive: <http://mailman.qth.net/mailman/private/amradio> List-Post: <mailto:[email protected]> List-Help: <mailto:[EMAIL PROTECTED]> List-Subscribe: <http://mailman.qth.net/mailman/listinfo/amradio>, <mailto:[EMAIL PROTECTED]> X-List-Received-Date: Wed, 29 Sep 2004 12:36:52 -0000 A very good choice! Build it right, and it works like a Swiss watch, and is quiet, no fans or blowers needed. 250 to 300 watts out easy, with plenty of audio to go with the carrier. The tubes are easy to find and cheap, there were many surplus = transformers that would power the setup nicely, mod transformer size is reasonable. Fair radio used to sell a Collins solder sealed power transformer that would give about 1000 volts at 600 ma full wave center tapped choke input, small size, 110 or 220 volt primary, used to go for $30.00! Variac it and it does 0 to 1500 volts, and will do the rf and mod decks if you want to keep things really simple. I have tried 812a's, 811a's, 572b's in the rf deck, and they all work fine and act the same as far as modulation, drive, and power output go. I have 3 old RCA mod transformers that work with this combo very well, and also work well with the pair of 813's and 4x150a's. 10,500 to 4350 ohms I think they are, and large! =20 They are around, a friend has a garage full of them. I retired the cvm5, as the freq response was quite poor. Building a homebrew rig is incredibly fun, and quite a source of pride if you take the time to build it RIGHT so it works trouble free for years and years, and looks nice. To get parts, you have to network hams, look on ebay, go to fests, buy old homebrew pieces of crap for the parts, and use some of the vendors that sell rf stuff. Even building receivers has not been a problem for me, parts are around, you just have to dig for them instead of going to one place like in the old days. Often, the prices are very reasonable, I picked up a bunch of nice oil filled caps for $10.00 each at Gaithersburg fest last year. I got about 6 of them. They still make new ones, but they wanted $120.00 each! The two big fun points are the chassis chess part, where you Figure out just where things are going, and how you are going to keep things symmetrical, rf and front panel, and the initial testing. Building something, and firing it up and finding it works great is quite fun, and the fun continues every time you use the rig. It also gives plenty to talk about, there is not a lot to say about a rice box into an amp. Old vintage ham gear like Johnson 500, Collins 30k-1, globe king = 400/500, and military surplus like the T368, art13, and others can be fun to play with, and sometimes turn up at reasonable prices (but not on ebay). 80 meter night time is hard to break into, and needs good power levels, but 40 in the daytime is very friendly and you can do nicely with 100 watts and up. Valliant's, the Collins 32v series, dx100's, and others in that power = class do very well on 40 meters, are fun to play with, and can be got at reasonable prices. People think they are expensive because they used to get them at fests for $10 or $20, but if you pay $500.00 for a 32v3, I think you got a lot of rig (and fun) for the money. The same money gets you an old crappy plastic rice box. Pay $3000.00 for a 30k-1 or some other bigger rig, and you have a lot of fun for the money, people spend that on little plastic boxes that put out 25 or 50 watts! For a lot of guys, playing with the equipment is as much fun as yakking into it. Brett N2DTS =20 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of John Coleman Sent: Tuesday, September 28, 2004 7:08 PM To: 'Discussion of AM Radio' Subject: RE: [AMRadio] Home Brew If I were going to build with tubes again and two hundred watts was the carrier output that I wanted. I would use a pair of 812s in push = pull class C and modulate with a pair of 811As push pull class B. Run about = 1500 volts @ 200 ma for 300 watts plate input on the 812s. Find a Modulation XFMR to match the output of 811A class B (about 12500 ohms as I = remember) to the 7500 ohm class C final.=20 John, WA5BXO
