Date: Thu, 11 Nov 93 04:30:36 PST 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 V93 #100 To: Ham-Homebrew Ham-Homebrew Digest Thu, 11 Nov 93 Volume 93 : Issue 100 Today's Topics: Ferrite Transformers LM2941 Sources Looking for dials ... Opto-isolator keying Phase-lock to WWV ? Rewinding transformers What do i need to get started? 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: Tue, 09 Nov 1993 16:20:50 GMT From: yuma!galen@purdue.edu Subject: Ferrite Transformers To: ham-homebrew@ucsd.edu In article perry@fc.hp.com (Perry Scott) writes: >Has anyone else tried prying apart one of those ferrite transformers >found in switching power supplies? Seems they are one amorphous mass >of ferrite, copper, transformer tape, and varnish. Ferrite is an >especially brittle substance. >I've tried pulling a few apart and have little ferrite shards all over >the shack. >Perry Scott >AA0ET The ferrites I've been able to get out of switching supplies didn't work too well at RF (I was on 6m, they may be OK at MF or HF). They were very lossy. I soaked the xfmr in a solvent to dissolve the tape adhesive and varnish. Then (wearing rubber gloves) I peeled off what I could and cut the rest with some big wire cutters, finally ending up with a core that was almost useless at the frequencies I was on. I've since broken down and bought an experimenter's kit from Amidon. I, too, have ferrite shards in the corners of the shack. Wear goggles! Galen, KF0YJ ------------------------------ Date: 8 Nov 1993 22:29:57 GMT From: olivea!charnel!yeshua.marcam.com!news.kei.com!sol.ctr.columbia.edu!howland.reston.ans.net!gatech!swrinde!cs.utexas.edu!cs.utexas.edu!geraldo.cc.utexas.edu!phmac118.ph.utexas.edu!bsn@@.. Subject: LM2941 Sources To: ham-homebrew@ucsd.edu Does anyone know of a source of LM2941T voltage regulators? This is a variable output voltage device with with a series PNP pass transistor. Barry Newberger, W5KH Inst. for Fusion Studies, UT-Austin Austin, TX 78712-1060 tel (512) 471-3726 fax (512) 471-6715 ------------------------------ Date: Wed, 10 Nov 1993 00:07:26 GMT From: munnari.oz.au!bruce.cs.monash.edu.au!trlluna!titan!pcies4.trl.OZ.AU!drew@uunet.uu.net Subject: Looking for dials ... To: ham-homebrew@ucsd.edu In article dmb@abacus.demon.co.uk (David Byrne) writes: >From: dmb@abacus.demon.co.uk (David Byrne) >Subject: Looking for dials ... >Date: Fri, 5 Nov 1993 11:29:23 +0000 > >Any homebrewers (esp. in the UK) know of a source for dials ? I'm building >a SW superhet, and looking for a decent dial/reduction drive to use for the >vfo, ideally something with about 36:1 reduction. I remember seeing a >reduction drive with selectable 6:1 and 36:1 ratios years ago, but can't >seem to get anything better than 10:1 these days. I could use a second >variable cap. in parallel with the primary cap. for electronic bandspread >I suppose, but I'd prefer to stay mechanical because I think calibrating >the freq. display dial will be easier. > >Any help appreciated, > >-David. >-- >David Byrne, Abacus Software, London, UK Tel: +44 71 930 4884 >Email: dmb@abacus.demon.co.uk Fax: +44 71 839 7445 >Here's a koan: If you have ice-cream I will give you some. If you have none, > I will take it away from you. (it's an ice-cream koan). Hello David. Similar problem here in Australia (any manufacturers reading this- great opportunity for a highly desirable item here- believe Ten Tec dials are rather good- how about it?). Second-hand at hamfests is about all you can hope for in the way of a really good unit- perhaps a nice Eddystone or Millen. Ocean State Electronics in Rohde Island USA (can supply address if you wish) still supply a good copy of the original Jackson Bros. 6:1 planetary drive. You can tandem two of them to get your 36:1 reduction with pretty good smoothness and acceptable backlash, provided you insert a good flexible coupler between drive and capacitor shaft. 73 Drew, VK3XU. ------------------------------ Date: 10 Nov 93 13:16:27 GMT From: news-mail-gateway@ucsd.edu Subject: Opto-isolator keying To: ham-homebrew@ucsd.edu Hi, My friend is building a keyer circuit using the Curtis Keyer chiip. He is trying to reduce the size and power cnsumption so he would like to use an opto isolator instead of a relay or transistor type circit for the output stage. His rig is a Kenwood TS-140S. He is interested in circuits which use opto-isolators to key transmitters and use little current. Any suggestions or references? Thanks and 73 Tom, kv2x -- ------------------------------------------------------------- | Thomas J. Jennings | Tel: (716) 273 7071 Development Engineer | Fax: (716) 273 7262 | ABB Process Automation | Post Office Box 22685 | Rochester, New York 14692-2685 | | ------------------------------------------------------------- Internet: jennings@jennings.rochny.uspra.abb.com ------------------------------------------------------------- ------------------------------ Date: 10 Nov 93 17:56:08 GMT From: ogicse!uwm.edu!vixen.cso.uiuc.edu!moe.ksu.ksu.edu!matt.ksu.ksu.edu!news@network.ucsd.edu Subject: Phase-lock to WWV ? To: ham-homebrew@ucsd.edu Ed Ellers writes: >Interestingly enough, since WWV's master clock site in Boulder doesn't have a >clear line of sight to the transmitters in Fort Collins, they have an >arrangement >with one of the Denver TV stations; they microwave a clock signal over to that >station (I've forgotten which one) and have gear there to phase-lock the color >subcarrier to it. At the WWV Fort Collins site they then take the signal off >air and phase-lock all their frequency standards to the burst; audio gets >there over a leased phone line from Boulder. When I went to NIST this summer and took their self-guided tour, I also picked up some time-reference documentation. It claims they use a microwave link to the transmitters in Fort Collins. It also says the WWV/WWVB clocks are compensated for the path delay. I would really doubt a goverment agency would use a commercial TV station for a time reference. -Steve Schallehn KB0AGD Kansas State University ------------------------------ Date: Tue, 09 Nov 1993 03:57:39 GMT From: nwnexus!ole!ssc!markz@uunet.uu.net Subject: Rewinding transformers To: ham-homebrew@ucsd.edu Michael Moroney (moroney@world.std.com) wrote: : The Radio Amateur's Handbook (at least older versions) give tips on : rewinding power transformers. I've never bothered rewinding one, but another good book is "Practical Transformer Design Handbook" by Lowdon. The old edition was from Sams, but I saw in an ad that the second edition is available from TAB Professional Books. Mark Zenier markz@ssc.wa.com markz@ssc.com ------------------------------ Date: 9 Nov 93 00:12:27 GMT From: organpipe.uug.arizona.edu!news@uunet.uu.net Subject: What do i need to get started? To: ham-homebrew@ucsd.edu I need to know what sort of equiptment i need in order to broadcast a signal that the FCC will ignore. My campus radio station only broadcasts over cable, and we are sick of it, so we are going to try going pirate, but we need some equiptment first. I've heard that there is a little transmitter that could be used to send a short signal, and you can place more antennaes around in order to get a bigger area within range-I NEED SOME ADVISE!! what do i need to get started? todd ------------------------------ Date: 9 Nov 1993 08:01:33 -0700 From: orca.es.com!cnn.sim.es.com!moons.sim.es.com!not-for-mail@uunet.uu.net To: ham-homebrew@ucsd.edu References <2bivng$ieo@reznor.larc.nasa.gov>, , -mail Reply-To : datwyler@moons.sim.es.com Subject : Re: My home brew.. Mutant Ninja 6m. Sounds fun. Pass the info please. TNX 73 -- Douglas L. Datwyler, WR7O Evans & Sutherland Computer Corp. preferred e-mail: datwyler@moons.sim.es.com ------------------------------ End of Ham-Homebrew Digest V93 #100 ****************************** ******************************