Date: Thu, 31 Mar 94 04:30:28 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 V94 #80 To: Ham-Homebrew Ham-Homebrew Digest Thu, 31 Mar 94 Volume 94 : Issue 80 Today's Topics: Building WWV time decoder Ramsey kits Semiconductor specs and equivalencies 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, 29 Mar 1994 22:04:28 GMT From: hookup!news.kei.com!eff!news.umbc.edu!europa.eng.gtefsd.com!howland.reston.ans.net!cs.utexas.edu!csc.ti.com!tilde.csc.ti.com!ticipa!asic.sc.ti.com!news@tcgould.tn.cornell.edu Subject: Building WWV time decoder To: ham-homebrew@ucsd.edu I know that WWV broadcasts the current time in a digital coded format. I would like to find information on this format. Better yet I would like to find a schematic for decoder circuit. Any info leading me in the right direction would be helpful. Thanks, Clay Timmons KB5SXS e-mail: ctimmons@asic.sc.ti.com ------------------------------ Date: Wed, 30 Mar 1994 10:00:21 GMT From: ihnp4.ucsd.edu!dog.ee.lbl.gov!agate!howland.reston.ans.net!gatech!wa4mei!ke4zv!gary@network.ucsd.edu Subject: Ramsey kits To: ham-homebrew@ucsd.edu In article drumhell@claudette.nrl.navy.mil (David Drumheller) writes: > I'm interested in getting on 440 mHz ... cheaply. So I would consider >building a Ramsey kit. (They cost about $160.) Questions: How easy are >they to build? Do they sell enclosures for them? How well to the radios >perform? How much test equipment do I need to calibrate and tune the >radio? Oh, oh, here we go again. The Ramsey kit is fairly easy to build, and yes they sell a cabinet. They don't perform that well, and you need sophisticated equipment, at least a spectrum analyzer, to tune them up properly. (Maximum output and cleanest output aren't even in the same ballpark) It's not a horrible choice if you have access to the right equipment. But you'd certainly come out cheaper, and have a higher performance radio, if you convert ex-commercial surplus radios such as Motorola or GE to amateur service. There'll be tons of those in the upcoming Dayton fleamarket for $50 or less. Gary -- Gary Coffman KE4ZV | You make it, | gatech!wa4mei!ke4zv!gary Destructive Testing Systems | we break it. | uunet!rsiatl!ke4zv!gary 534 Shannon Way | Guaranteed! | emory!kd4nc!ke4zv!gary Lawrenceville, GA 30244 | | ------------------------------ Date: Tue, 29 Mar 1994 18:37:11 GMT From: ihnp4.ucsd.edu!dog.ee.lbl.gov!agate!howland.reston.ans.net!usenet.ins.cwru.edu!news.ysu.edu!malgudi.oar.net!witch!ted!mjsilva@network.ucsd.edu Subject: Semiconductor specs and equivalencies To: ham-homebrew@ucsd.edu In article , John J Welch (jwelch@acsu.buffalo.edu) writes: >Dear Net: > >This seems like the relevant area to post since it is likely to be >read by both amateur and professional electronics people who work hands-on >everyday with semiconductors of all sorts, if another group would be >more appropriate, please email me. > >Question: Is there a resource which one can consult, preferably online, to >get design specifications on semiconductor components and to determine >equivalencies between components for purposes of substitution? > >I am familiar with semiconductor catalogs which list chips from each >manufacturer, but this seems like an archaic way to go about searching. >In addition to the awkwardness of thumbing through these tomes, it would >seem too expensive to maintain libraries of these catalogs and keep them >up to date. > >I am interested only from the perspective of a hobbiest trying to maximize >the utility of his junk collection. There are several projects I would like >to try, but years after the projects have been written up, parts numbers >change, better substitutes come out, etc. > > I don't have any knowledge of an online source, but one very good reference for mystery parts are the NTE, ECG and SK catalogs/cross-reference guides. These guides will cross-reference just about any semi you have to an equivalent (or slightly superior) device, and you can read the thumbnail specs on that device in the guide. You soon learn some of the part numbers by heart (e.g. the NTE 123A is your basic 2N3904/PN2222/etc). These guides cost $3-$4 and are readily available. Of course, the more exotic the device the less likely it is to be listed, but for hobby purposes we're generally using more common, available devices anyway. Another point to be aware of is that the equivalent devices may have slightly better specs than the device you're looking up (higher voltage, higher gain, etc). This might get you into trouble if you cross-reference desired part AAAA to (e.g.) ECG part BBBB and find that the BBBB is also the cross for a part CCCC, which you just happen to have. The CCCC may not be as "good" as the AAAA, depending. Most of the time, though, you should be OK. BTW, I think some of these companies now have their cross-references on disk also. 73, Mike, KK6GM ------------------------------ End of Ham-Homebrew Digest V94 #80 ****************************** ******************************