Date: Mon, 8 Nov 93 04:30:25 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 #97 To: Ham-Homebrew Ham-Homebrew Digest Mon, 8 Nov 93 Volume 93 : Issue 97 Today's Topics: How to calibrate a DVM My home brew.. (2 msgs) Radio Shack WeatherRadio Modification/Schematic Rewinding transformers 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: Fri, 5 Nov 1993 00:53:12 GMT From: news.kpc.com!amd!amdahl!netcomsv!netcom.com!btoback@decwrl.dec.com Subject: How to calibrate a DVM To: ham-homebrew@ucsd.edu In article rem@tc.fluke.COM (Randy Mather) writes: >In article <2b3ol3$nph@gdls.gdls.com> turini@gdls.com (Bill Turini) writes: > >>I have three digital voltmeters in my shack, none of which agree with the >>others. >> >>The problem I have is how to calibrate the voltage. I have heard that >>mercury cells like those used in cameras are quite stable and consistent >>in voltage and that they can be used to calibrate a meter. Has anyone had >>experience with this? Will it work? Is there a better way? > >One thing you can do is find a meter that has been calibrated recently >say from a friend or at work and check the meters against it. Using >mercury cells can be tricky and not all meters are alike. One other thing you can do is send one of the three DVMs to a calibration lab and pay the $50 or so they'll charge you. Then calibrate the other two using the first as a standard. Not cheap or clever, but straightforward. -- Bruce Toback ------------------------------ Date: Sat, 6 Nov 1993 21:53:58 GMT From: sdd.hp.com!math.ohio-state.edu!sol.ctr.columbia.edu!news.kei.com!ub!csn!teal.csn.org!dfeldman@network.ucsd.edu Subject: My home brew.. To: ham-homebrew@ucsd.edu Well I just sampled the last of my 3 batches of home brew and they all came out great (an ale, a bock, and a wheat). I just want to know why my homebrew radio projects don't improve with age... 73 - wb0gaz ------------------------------ Date: 7 Nov 1993 14:12:00 GMT From: sdd.hp.com!cs.utexas.edu!usc!elroy.jpl.nasa.gov!news.larc.nasa.gov!grissom.larc.nasa.gov!kludge@network.ucsd.edu Subject: My home brew.. To: ham-homebrew@ucsd.edu In article dfeldman@teal.csn.org (Dave Feldman) writes: >Well I just sampled the last of my 3 batches of home brew and they all >came out great (an ale, a bock, and a wheat). I just want to know why >my homebrew radio projects don't improve with age... 73 - wb0gaz Oh, they do, they do. A few hundred hours of burn-in, and that PTO will be a lot more stable. On a more interesting note, I got my first international contact with the $10 Teenage Mutant Ninja Turtle HT, recrystalled for 6M and with an added amplification stage on the output for almost half a watt of power. Okay, so it was only Canada, but it's still going to be a lot of fun to fill out the EQUIPMENT: field on the QSL card. --scott -- "C'est un Nagra. C'est suisse, et tres, tres precis." ------------------------------ Date: 8 Nov 93 00:41:23 GMT From: att-out!cbnewsh!mrb1@rutgers.rutgers.edu Subject: Radio Shack WeatherRadio Modification/Schematic To: ham-homebrew@ucsd.edu Hi --- The library where my wife works went out and bought a Radio Shack WeatherRadio Alert, Model 12-140 to let them know when there will be bad weather, etc. Unfortunately, the person purchasing it did not get the instruction book. Well, they did manage to set it up and get it to work OK but they find the alert noise to be too unnerving (especially in a quiet place like a library). What they really need is for the darn thing to stay muted until there is an alert, and then the speaker unmutes and everyone can hear the message .... not the way it presently works where it squeals away until someone presses the WEATHER button to hear the announcement. My first thought was to open it up and clip a lead on the little piezoelectric sounder or whatever is in there that makes the alert noise. But upon opening it up carefully, it appears as though the alert noise is summed with the receiver audio before amplification & going out the speaker. And without a schematic, I'm a bit reluctant to do much more. Plus how would you know there was an alert so you could hit the WEATHER button and hear it ?! So here's the question(s) --- There's a little switch on the back bottom plate marked "ALERT LOCK" --- will this make the receiver do what I want? What does it do? -and/or- Does anyone have a schematic who can tell me what lead to lift to kill the alert tone & make the speaker unmute instead ? -and/or- Can someone with a schematic advise where the alert tone audio is generated and summed in, so I can attenuate to a bearable level ? I would appreciate any and all replies (and anyone suggesting a modification is absolved of all responsibility). E-mail preferred as I am posting to several relevant groups. Thank you in advance, Maurice R. Baker, WA3ZXO ATT&T Bell Labs, Holmdel NJ reply to mrbaker at attmail.com (or this message) ------------------------------ Date: Fri, 5 Nov 1993 19:21:34 GMT From: dog.ee.lbl.gov!agate!howland.reston.ans.net!math.ohio-state.edu!cs.utexas.edu!utnut!torn!csd.unb.ca!garfield.csd.unbsj.ca!robert@network.ucsd.edu Subject: Rewinding transformers To: ham-homebrew@ucsd.edu Hi, Ok, it was a long and bloody battle (blood from occasionally slipping and jabbing my hands on a corner of the lamination!), but I have emerged victorious! Now comes the rough spot...unwinding and rewinding. And as most pointed out, don't forget to re-varnish the laminations. Thanks to all those to posted and e-mailed. 73 de VE1RKF -- ====================== Robert Ford (VE1RKF) robert@unbsj.ca ====================== ------------------------------ Date: Sun, 7 Nov 1993 18:59:42 GMT From: agate!usenet.ins.cwru.edu!magnus.acs.ohio-state.edu!csn!teal.csn.org!dfeldman@ames.arpa To: ham-homebrew@ucsd.edu References , <2bivng$ieo@reznor.larc.nasa.gov>, -st Subject : Re: My home brew.. In article andrews@fms.com (Andrew Sargent N8OFS) writes: >In article <2bivng$ieo@reznor.larc.nasa.gov> kludge@grissom.larc.nasa.gov (Scott Dorsey) writes: >>In article dfeldman@teal.csn.org (Dave Feldman) writes: >>>Well I just sampled the last of my 3 batches of home brew and they all >BTW (for DAVE), I've been drinking alot of micro-brewrey beer. It's >all over the place. Of course, you can always send me a bottle and >I'll tell ya how it rates... You really wouldn't want to mess with my latest project -- a 2 meter transverter for a ten-tec argonaut - but I'll let it age 6 months and maybe next spring you can give it a try... I also would like to see the info on the 6M QRP xcvr... 73 (belch)! ------------------------------ End of Ham-Homebrew Digest V93 #97 ****************************** ******************************