Date: Wed, 4 May 94 04:30:21 PDT From: Ham-Homebrew Mailing List and Newsgroup Errors-To: Ham-Homebrew-Errors@UCSD.Edu Reply-To: Ham-Homebrew@UCSD.Edu Precedence: Bulk Subject: Ham-Homebrew Digest V94 #118 To: Ham-Homebrew Ham-Homebrew Digest Wed, 4 May 94 Volume 94 : Issue 118 Today's Topics: FTP site with 16,000 CIRCUIT references Idea, 10-10 members.... index R2 T2 pcb source wanted Screen voltage on 4CX250B's: One more question... SEARCHING FOR LOW POWER FM TRANSMITTER for BROADCAST BAND (2 msgs) Vertical yagi mounting Send Replies or notes for publication to: Send subscription requests to: Problems you can't solve otherwise to brian@ucsd.edu. Archives of past issues of the Ham-Homebrew Digest are available (by FTP only) from UCSD.Edu in directory "mailarchives/ham-homebrew". We trust that readers are intelligent enough to realize that all text herein consists of personal comments and does not represent the official policies or positions of any party. Your mileage may vary. So there. ---------------------------------------------------------------------- Date: 29 Apr 1994 16:37:16 GMT From: ihnp4.ucsd.edu!agate!howland.reston.ans.net!torn!nermal.cs.uoguelph.ca!herman.cs.uoguelph.ca!psawatzk@network.ucsd.edu Subject: FTP site with 16,000 CIRCUIT references To: ham-homebrew@ucsd.edu Thought this group would be a good place to make it known that we have a database of about 16,000 bibliographic references (from over 350 magazines/journals) of articles/papers containing practical electronic circuit designs. Just ftp gaitlab1.uwaterloo.ca Directory /pub/circuits/demo contains a small demo. Directory /pub/circuits/main has the big one (~3Mbytes before unzipping, ~9Mbyte after) [be sure to give a bin command before getting the binary files] The database has a front end for searches on title, device numbers (eg 741, 2N3904, MC1496, etc.), and circuit descriptions. The individual files are also dBASE-compatible, so if you don't like the front end you can use many other utilities to extract data. Subject matter covers just about every field, including RF, audio, computers, interfacing, DSP, etc. Copyrights are honored (registered with CCC - the Copyright Clearance Center), so if anyone needs hard copy of articles from those periodicals that qualify, they can get them. We're hoping to update annually or semi-annually. Any comments and suggestions are welcome. -- ============================================================================== Peter Sawatzky >>> e-mail psawatzk@uoguelph.ca <<< ------------------------------ Date: Tue, 3 May 1994 19:10:20 GMT From: darwin.sura.net!rsg1.er.usgs.gov!news.cs.indiana.edu!noose.ecn.purdue.edu!constellation.ecn.purdue.edu!wb9omc@seismo.css.gov Subject: Idea, 10-10 members.... To: ham-homebrew@ucsd.edu I'd like to gauge the interest among members of 10-10 International who are on the Internet for a group, possibly called: rec.radio.amateur.1010 The purpose of the group would be multiple: 1) to help disseminate information of general interest to 10-10 members who have access to Internet. 2) to help 10-10 members set up skeds, nets and other communications events. 3) to help develop interest in not only 10-10 International but to maintain interest in 10 meters in *spite* of the current lull in the band. 4) to help develop computer operating aids for 10-10 contests and paperchasing. 5) to serve as one focal point for 10-10 members to discuss the organization, contest rules, awards rules, etc. 6) other future purposes realted to Amateur Radio and 10-10. *********** I think that emailing me would probably be preferred to clogging up a number of newsgroups with "me too!" kinds of mail. If you are interested or have a *brief* thought on the subject, please email: wb9omc@harbor.ecn.purdue.edu flames and/or mail bombs will be ignored, deleted, /dev/null'ed, etc. :-) If interest seems positive enough, I will make some contacts with the officers of 10-10 to find out in what ways, if at all, they would like to make contact and maintain contact with such a newsgroup. 73 Duane, WB9OMC ------------------------------ Date: Tue, 3 May 94 14:14:00 -0400 From: elroy.jpl.nasa.gov!swrinde!cs.utexas.edu!utnut!torn!uunet.ca!uunet.ca!portnoy!canrem.com!noel.reyes@ames.arpa Subject: index To: ham-homebrew@ucsd.edu index quit ------------------------------ Date: 3 May 1994 08:13:02 -0400 From: hp81.prod.aol.net!search01.news.aol.com!not-for-mail@uunet.uu.net Subject: R2 T2 pcb source wanted To: ham-homebrew@ucsd.edu In article , rohrwerk@orac.holonet.net (John Seboldt) writes: >Source for R2 T2 Boards and parts I spoke with Rick Campbell in January after sending an order to Applied Radio Science in November 93. He was very pleasant, and said that the QST articles had unleashed a torrent of orders, suggestions and comments. The poor guy wasn't planning to make a living mailing out PC boards, and was trying to get everyone taken care of. He asked me to be patient, said there were some changes being made to the art work and that they would be along. He was right. In mid-April, the very nicely made boards arrived, along with updated schematics and complete parts lists, including catalog numbers from DigiKey, Mouser and other sources. I do not know if the rumor that he is no longer accepting orders is true. But he has honored the orders of everyone that I know of -- sometimes it just takes a while. Jonathan Cain N4SUP ------------------------------ Date: Mon, 2 May 1994 12:38:33 GMT From: ihnp4.ucsd.edu!usc!math.ohio-state.edu!darwin.sura.net!mlb.semi.harris.com!controls.ccd.harris.com!drs@network.ucsd.edu Subject: Screen voltage on 4CX250B's: One more question... To: ham-homebrew@ucsd.edu NX7U (nx7u@aol.com) wrote: : In article , dgf@netcom.com (David Feldman) writes: : >Or should I give up on the whole mess and go for grounded grid ;-) : My input: on the smaller tetrodes like the 4CX250B, grounded grid does not : absolve you from supplying screen voltage. Many, many times have the EIMAC : guys written that you don't tie grid and screen together in cathode-driven with : small tetrodes, because that darn screen will still draw current and melt down. : You can (of course) do it with "higher perveance" tubes like 4-400A, 4-1000A, : etc. But, unfortunately, you're still stuck with the screen supply! -- I must have missed the original post for this. I understand that it is best to provide both screen voltage and grid bias voltages for a cathode driven 4CX250 tube (grounded grid). I'm not sure what the ideal voltages are, but would guess that at 2kv plate voltage, you might want something about -100 grid and +250 screen. The data sheets would tell you for sure. --------------------------- | Doug Snowden | | N4IJ | | email: drs@ccd.harris.com | --------------------------- ------------------------------ Date: 3 May 94 20:18:28 GMT From: sdd.hp.com!hp-pcd!hpspkla!darsmith@hplabs.hpl.hp.com Subject: SEARCHING FOR LOW POWER FM TRANSMITTER for BROADCAST BAND To: ham-homebrew@ucsd.edu : : If you buy the kit from Ramsey Electronics, you'll get part of the : regulations. OK, please post the number or address for Ramsey Electronics. Thanks Daryl Smith darsmith@hpspkla.spk.hp.com ------------------------------ Date: 29 Apr 1994 23:29:50 -0600 From: ihnp4.ucsd.edu!mvb.saic.com!MathWorks.Com!yeshua.marcam.com!charnel.ecst.csuchico.edu!xmission!u.cc.utah.edu!not-for-mail@network.ucsd.edu Subject: SEARCHING FOR LOW POWER FM TRANSMITTER for BROADCAST BAND To: ham-homebrew@ucsd.edu Rich Krinsky (rich@cmc) wrote: Chopped and Edited at will....... : I am interested in designing an FM transmitter for broadcast in the FM band. : The device will be digitally tuned (not with a screwdriver!). : 1. Does anyone have any design information for such a product? You can order a complete kit or just schematic from Rasmey Electronics. : 3. Has anyone taken the guts of a cordless phone and modified it for this? It would seem that : this would be the most "elegant & inexpensive solution". Wouldn't be worth the effort, you could make one eaiser. And, much cheaper. : 4. Does anyone know where I can download a copy of the FCC regs regarding broadcast in the FM : band? I believe that is: TITLE 47, PART 15. If you buy the kit from Ramsey Electronics, you'll get part of the regulations. Mike Miles ------------------------------ Date: Tue, 3 May 1994 11:01:55 GMT From: ihnp4.ucsd.edu!dog.ee.lbl.gov!agate!howland.reston.ans.net!pipex!bbc!ant!boyer@network.ucsd.edu Subject: Vertical yagi mounting To: ham-homebrew@ucsd.edu William P. Osborne (wosborne@nmsu.edu) wrote: : On Thu, 28 Apr 1994 20:55:12 GMT, : Paul H. Bock wrote: : > In a recent on-the-air discussion, I pointed out the error : >of mounting a two-meter yagi in the vertically-polarized : >position while using a metal mast (assuming that the antenna : >mounts from the center of the boom and not at one end, the : >latter being common for 3- and 4-element yagis). : Paul: This is an excellent problem for testing with the newer versions of : MIninec or NEC on the market. I have done a good bit of modeling of : stacked and interlaced 10/15/20 meter yagis and can confirm that a 20 meter : element in the middle of a 15 meter yagi is bad news in that it can cost : you 1 to 1.5 dB of gain, change the input Z some and cause most anything to : happen to the front to back. I have not tried a random length mast but I : would expect the same sort of results. 73 Bill I did a little modelling with NEC. I first constructed a rough 4 ele yagi and got a resonable pattern. Then I added a long vertical pole roughly in the center of the yagi. This really buggered the pattern. Ok so I did this at Band II where I have a good idea of the size of things off the top of my head, but it still applies to 2m. Here is my NEC input file. CM vertical Yagi CM CM CE GW1,25,0.,0.,-.9,-.,0.,.9,.01, GW2,25,.76,0.,-.76,.76,0.,.76,.01, GW3,25,1.3,0.,-.6,1.3,0.,.6,.01, GW4,10,1.9,0.,-.6,1.9,0.,.6,.01, GW5,25,1.,0.,-2.65,1.,0.,.35,.03, GE0,0,0., EX0,2,13,00,1.,0., FR0,1,0,0,96.,0.,0., RP0,1,359,1010,90.,0.,0.,1.,0.,0., EN So I guess the answer is don't use a metal pole with a vetical yagi. John B John.boyer@rd.eng.bbc.co.uk ------------------------------ End of Ham-Homebrew Digest V94 #118 ******************************