Date: Sun, 26 Dec 93 04:30:24 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 #144 To: Ham-Homebrew Ham-Homebrew Digest Sun, 26 Dec 93 Volume 93 : Issue 144 Today's Topics: - - television disruptor - - Charging Deep-Cycle Batteries from Automobile Crystal Radios (2 msgs) Needed: Simple TX Amp for FM Mic 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: 26 Dec 1993 09:47:09 GMT From: usc.edu!elroy.jpl.nasa.gov!bondi.jpl.nasa.gov!chu@network.ucsd.edu Subject: - - television disruptor - - To: ham-homebrew@ucsd.edu quixote@eskimo.com (Looking for Sancho) writes: > The intended use of this device is to be put with a timer > against the wall where my new neighbor has his television set. > He comes home around midnight and keeps his television > loud until 3 am almost every day. I wonder about the legality > of my idea, therefore I would like something with regulated > signal strength since I would not like to affect other neighbors. I had this problem with a neighbor in an apartment that I used to live in. I considered talking to her about her TV, but realized that it would have done no good since her snoring would actually come through, over the noise of the TV. I eventually moved into my own house, on a corner lot, with a tree farm behind me, and only one neighbor to the far side from my bedroom and audio room. I could boom well into the night if I wanted to (and did). I know this doesn't solve your problem, but I think the first step should be to talk to him. Failing that, talk to the apartment manager. Failing that, call the cops. If you go through with your TV jammer, it might just become him calling the cops on you. eyc ------------------------------ Date: Sat, 25 Dec 1993 14:46:35 GMT From: swrinde!emory!rsiatl!ke4zv!gary@network.ucsd.edu Subject: Charging Deep-Cycle Batteries from Automobile To: ham-homebrew@ucsd.edu In article eesnyder@beagle.Colorado.EDU (Eric E. Snyder) writes: >I have been thinking about battery setups for remote HF/VHF >station. From what I have read, the deep cycle marine/RV >batteries are the way to get a good strong 12 volt DC power >supply. Yes they are. They are designed for the deep discharges that rapidly kill auto cranking batteries, and they're relatively cheap. However, they are still messy wet cells that can outgas or leak. The *really* good batteries are the traction gel cells, but they are still seriously expensive. The 26 used in the GM Impact cost $1250 *each*. But they'll last 3 years and put out a combined 100 kW peak. >However, I am wondering what the best way to charge >such cells. Can I simply run a set of jumper cables from >my car battery to the cell while I am driving? Do I need any >sort of regulation or will my car's electrical system take >care of this? Well it might take *long* jumper cables if you're driving. :-) You can charge your deep cycle station batteries off an idling car, but that's rather inefficient, and the charging is not well controlled. Most of these batteries sulphate and boil off hydrogen if charged rapidly. It's better to slow charge them for long life. Their chemistry is enough different from cranking batteries that using the same methods isn't an ideal way of charging them. >Any suggestions or references would be greatly appreciated. >The reading I have done consists mainly of an article in QST >on solar-powered stations... so, of course, it didn't talk >a lot about other ways to charge the batteries. Write or call the major battery manufacturers. They have good application notes and catalogs that they will be happy to send you on how to treat their batteries for best results. In general, most will tell you that you should use a constant voltage charger with current limiting, and that there's really no substitute for wet hydrometers for monitoring cell state of charge. 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: Sat, 25 Dec 1993 18:01:18 GMT From: library.ucla.edu!agate!iat.holonet.net!kafka@network.ucsd.edu Subject: Crystal Radios To: ham-homebrew@ucsd.edu I am looking for any information on crystal radios. I will buy photocopies or originals of books/periodicals. If you know of any other sources for info let me know. Thanks ------------------------------ Date: Sat, 25 Dec 1993 18:54:50 GMT From: library.ucla.edu!agate!spool.mu.edu!torn!nott!cunews!freenet.carleton.ca!FreeNet.Carleton.CA!ab510@network.ucsd.edu Subject: Crystal Radios To: ham-homebrew@ucsd.edu In a previous article, kafka@iat.holonet.net (Marc McNulty) says: > >I am looking for any information on crystal radios. I will buy >photocopies or originals of books/periodicals. If you know of any other >sources for info let me know. > >Thanks > I have an interesting article on xtal sets from a popular book some years ago. it consists of 2 xtal sets "in series"- the second one generating voltage to fire up a single transistor audio amp to drive a spkr for the first set. If you are interested email your address and I will send you a paper copy. Cheers and Merry Xmas- George VE3KIA Ottawa, Canada. -- GEORGE ATTALLAH - VE3KIA -OTTAWA CANADA "THE LAST SURVIVOR OF THE GROUP OF ONE" "THE ONLY ONE IN CAPTIVITY" ------------------------------ Date: Sun, 26 Dec 1993 07:16:52 GMT From: usc.edu!howland.reston.ans.net!newsserver.jvnc.net!newsserver.technet.sg!ntuix!ntuvax.ntu.ac.sg!asirene@network.ucsd.edu Subject: Needed: Simple TX Amp for FM Mic To: ham-homebrew@ucsd.edu There are many simple FM mic type transmitter circuits out ther utilizing Hartley and Colpitts oscilators but most of these are quite weak in terms of power out put and yields a typical range of about 100 to 200 meters in built up areas. Does anyone out there know /have a simple to build amplifier which can say increase this to a few kilometers but retaining the simplicity of the oscillator section? A simple schematic would be nic without needing too many hard to get parts., maybe using a 2N3866 and air wound coils. Any one out there with design expertise? Help! 73s de 9VG Daniel ------------------------------ End of Ham-Homebrew Digest V93 #144 ****************************** ******************************