Date: Mon, 7 Mar 94 04:30:40 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 #52 To: Ham-Homebrew Ham-Homebrew Digest Mon, 7 Mar 94 Volume 94 : Issue 52 Today's Topics: GPS Receiver Boards Help understanding FM and SSB Looking for Lex... Need info on Toshiba TC571000D-20 EPROM Power FET Gate Modulation - Need Info Ramsey SA-7 broadband preamp Tuner-tuner 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: 7 Mar 1994 04:47:08 GMT From: ihnp4.ucsd.edu!sdd.hp.com!hpscit.sc.hp.com!rkarlqu@network.ucsd.edu Subject: GPS Receiver Boards To: ham-homebrew@ucsd.edu The Motorola GPS receiver is less than $150 in 100's. It has six channels and just about all the features you would ever want. Rick Karlquist N6RK rkarlqu@scd.hp.com ------------------------------ Date: 1 Mar 94 15:59:24 GMT From: agate!usenet.ins.cwru.edu!howland.reston.ans.net!pipex!warwick!not-for-mail@ucbvax.berkeley.edu Subject: Help understanding FM and SSB To: ham-homebrew@ucsd.edu I've read the RSGB's RAE manual, and still have difficulty with their descriptions of FM and SSB. In FM, as I understand, the frequency of the carrier is modulated by the amplitude of the speech. So why does the bandwidth of the RF signal matter? If you have, say a 28Mhz carrier and the bandwidth of the Rf signal is 5kHz, why should that limit the audio bandwidth to 5Khz? If you send a 20kHz audio signal surely the RF signal would just oscillate between 28Mhz+-5kHz at 20kHz? I realise that filtering the output is important to remove any harmonics, but as you can see I'm quite confused about the bandwidth issue. The other thing is SSB. I get the general idea of using power more efficiently by sending half the audio waveform as the other half is going to be a mirror image, and removing the carrier as we want to concentrate power on the signal instead of the carrier. What I don't get is how one removes the carrier and then adds it back again. Can someone explain that, please? Cheers, Jason -- Jason L Saunders - President, Warwick Thrash n' Burn Society email: maupb@csv.warwick.ac.uk - PGP 2.2 key available on request snail: 57 Gordon Street, Earlsdon, Coventry CV1 3ET, ENGLAND "At least you know a sicko's committed" ------------------------------ Date: 3 Mar 94 18:08:27 GMT From: ihnp4.ucsd.edu!usc!cs.utexas.edu!convex!news.utdallas.edu!wupost!udel!news.sprintlink.net!connected.com!beauty!rwing!eskimo!mzenier@network.ucsd.edu Subject: Looking for Lex... To: ham-homebrew@ucsd.edu In <60290@uugate.wa7slg.ampr.org>, ka7oei@uugate.wa7slg.ampr.ORG wrote: : I'm looking for a Lexical Analyzer for DOS. : How about a 'port of "lex"? Does anyone know where one may be found? In my travels, I've run across at least 3 versions of Lex implemented in C. (And another that does Turbo Pascal.) First, there's AT&T Lex. You can't get the source to this. (A version of AT&T Yacc was out, but AT&T sicced their lawyers on people. No bit deal, Bison and Byacc are as good or better.) Next, there's a Lex written at University of Waterloo (by Charles Forsythe?) that was released on a DECUS souce code tape. It has an incompatible source languge format. This was available as a port to DeSmet C (a now obselete "classic" ie. Version 7 level compiler) from the C Users Group, sold (for a while) by the Austin Code Works, and is (I think) the lex in the MSDOS/C directory in the Simtel echos sites C. Finally, there's Flex. This is a souped up Lex written at UCB that is the most common. It gains its performance improvement at the expense of radically incompatible file input compared to AT&T Lex, but as it's now the defacto standard, this is the route to take. Available in the TXTUTL, GNUISH and DJGPP directories under MSDOS on a Simtel echo. Also just about every where else (Linux release, C Users Group, Austin Code Works, and wherever comp.sources.misc is archived ). Mark Zenier mzenier@eskimo.com markz@ssc.com ------------------------------ Date: 5 Mar 94 19:55:41 GMT From: nprdc!ihnp4.ucsd.edu!swrinde!cs.utexas.edu!convex!darwin.sura.net!rouge!agh0792@network.ucsd.edu Subject: Need info on Toshiba TC571000D-20 EPROM To: ham-homebrew@ucsd.edu I am working with a system that uses a TOSHIBA TC571000D-20 EPROM. I was only able to find a National Semiconductor EPROM chip - NM27C010Q200. The latter is a 1 meg (128Kx8) CMOS EPROM 200 ns. I was told that this chip would work as a substitute for the Toshiba chip. Can anyone verify that? I have the pin-out for the National Semiconductor chip. Does anyone have the pin-out / other info for the Toshiba Chip? Thanks in Advance. I need to know the answer this weekend if possible. Regards, aghill@usl.edu p.s. the chips each have 32 pins. . ------------------------------ Date: 6 Mar 1994 17:20:54 -0800 From: nntp.crl.com!crl.crl.com!not-for-mail@decwrl.dec.com Subject: Power FET Gate Modulation - Need Info To: ham-homebrew@ucsd.edu I would appreciate any information on the use of power type FETS (Hexfet, TMOS, etc.) in AM transmitter applications. I have some references for this but they are rather incomplete, I am particulary interested in gate modulation techniques to eliminate the sereis type modulator. Thanks Stephen Dunifer ------------------------------ Date: 5 Mar 1994 10:30:25 GMT From: ihnp4.ucsd.edu!usc!howland.reston.ans.net!usenet.ins.cwru.edu!cleveland.Freenet.Edu!eb795@network.ucsd.edu Subject: Ramsey SA-7 broadband preamp To: ham-homebrew@ucsd.edu Hello. I would like to know if any of you here on r.r.a.h have assembled and used the Ramsey SA-7 preamp. I am planning to get a few of them and use them for TV and FM DX. I will have one for FM, one for UHF, and one for VHF. I have three seperate antennas for those bands, and seperate feed lines too. Will it be difficult to design a filter system where only the de esired band(ie FM, or UHF TV) get amped by the SA-7? I plan on buying three of them, and I would like to know what I am getting into before I plunk down the $$$. By the way, here are some specs: freq range:100kHz to 1000mHz gain:>20dB noise figure: < 4dB NEC microwave transistors are used in the design. They are $14.95 each in kit form from Ramsey. Ramsey is at: (716)924-4560 Thanks. -- Eric Matthews eb795@cleveland.freenet.edu ------------------------------ Date: Sat, 5 Mar 1994 15:12:05 GMT From: ihnp4.ucsd.edu!swrinde!cs.utexas.edu!convex!news.utdallas.edu!wupost!csus.edu!netcom.com!tgm@network.ucsd.edu Subject: Tuner-tuner To: ham-homebrew@ucsd.edu Richard McAllister (rfm@urth.eng.sun.com) wrote: : 2. how can I build one? [this is why this is in r.r.a.homebrew and not .misc] You can build one for about $10 or so. It is just a variation on a noise bridge. My 1990 ARRL Handbook has a schematic. RadioKit also sells a noise bridge. Or you could get the MFJ noise bridge for about $50. Set the controls on the noise bridge to 0 reactance and 50 ohms resistance before you tune. I built one from the Ham Radio Magazine articles a few years ago. It really works. Thomas Ki4N ------------------------------ End of Ham-Homebrew Digest V94 #52 ****************************** ******************************