Date: Tue, 1 Feb 94 04:30:27 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 #16 To: Ham-Homebrew Ham-Homebrew Digest Tue, 1 Feb 94 Volume 94 : Issue 16 Today's Topics: Antenna Tuner Project Advice Needed Crazy VFO Reciprocal mixing at 25 kHz, ICF-2010 Help! The World's Smallest Receiver 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: 28 Jan 94 11:20:41 From: news.mentorg.com!hpcan240.mentorg.com!hpcan240!c2k@uunet.uu.net Subject: Antenna Tuner Project Advice Needed To: ham-homebrew@ucsd.edu In article <2i651o$pfd@hp-col.col.hp.com> jms@col.hp.com (Mike Stansberry) writes: Path: hpcan240.mentorg.com!news.mentorg.com!uunet!haven.umd.edu!news.umbc.edu!europa.eng.gtefsd.com!howland.reston.ans.net!usc!elroy.jpl.nasa.gov!newncar!csn!col.hp.com!jms From: jms@col.hp.com (Mike Stansberry) Newsgroups: rec.radio.amateur.homebrew Subject: Re: Antenna Tuner Project Advice Needed Date: 26 Jan 1994 16:16:56 GMT Organization: HP Colorado Springs Division Lines: 23 Message-ID: <2i651o$pfd@hp-col.col.hp.com> References: NNTP-Posting-Host: mssjms.col.hp.com X-Newsreader: TIN [version 1.2 PL0.7] Bruce Pea (pea@wri.com) wrote: : I'm getting ready to put a dipole up and use ladderline to : feed it. I'm going to need an antenna tuner so I can tune : this wire across 160-10m. : I thought building a tuner would be a nice winter project. : Do any of you have a favorite tuner project you would like : to point me to?? My rig is an ICOM IC-740, 100 watts out. : Thanks for the help! There are a lot of antenna coupler designs, and some folks have favorites that they defend quite strongly, however, I've had good luck with the 'Ultimate Transmatch' design that can be found in older ARRL Amateur Radio Handbooks. Another design that is supposed to be good is the 'Series Parallel Capacitance (SPC)' that is shown in newer handbooks. I tried it and couldn't get it to do what I wanted, so went back to the 'Ultimate'. I haven't given up on the SPC, though, and have plans to try it again. Mike, K0TER I'll second Mike's comments on the "Ultimate". I built one in the seventies, as did a friend. I tested mine in a configuration I expected to use and called it good. My friend tested it at 100 Watts on 20 meters into a coathanger hanging over the curtain rod. It CAUGHT THE CURTAINS ON FIRE! (but it did load...&-> ) Cheers, Carl -- ------------------------------------------------------------------- My opinions are mine, (all mine), and do not necessarily reflect those of my employer. Carl Ketcham carl_ketcham@mentorg.com WA7ZBV Mentor Graphics, Suite 300, 5295 South 300 West, Murray, Utah 84107 ------------------------------------------------------------------- ------------------------------ Date: 28 Jan 1994 18:20:36 GMT From: usc!howland.reston.ans.net!vixen.cso.uiuc.edu!sdd.hp.com!hpscit.sc.hp.com!rkarlqu@network.ucsd.edu Subject: Crazy VFO To: ham-homebrew@ucsd.edu In article <2iahed$k2u@olivea.atc.olivetti.com>, Roberto Valfredini wrote: >Now the problem is that if I put the vfo inside its metal box >to make it usable and connecting the box itself to the ground of the >vfo (as it should be ) etc etc ... >In a few words putting it in its >final state then it starts to become instable increasing or decreasing >its frequency of more than 800 or more Hz and trying to drift also after >more than 1 hour from power-up. > >IT IS DRIVING ME CRAZY !!!!!! Usually, I have found that "unexplainable" oscillator problems can be traced to UHF oscillations. Many colpitts oscillators have a capacitor from the base to ground. At UHF, the transistor becomes a grounded base amplifier, and you know how easily those things oscillate! Try putting a ferrite bead on the base lead of the transistor. Rick Karlquist N6RK rkarlqu@scd.hp.com ------------------------------ Date: 28 Jan 1994 23:44:14 GMT From: agate!doc.ic.ac.uk!pipex!howland.reston.ans.net!vixen.cso.uiuc.edu!sdd.hp.com!col.hp.com!srgenprp!news.dtc.hp.com!hpscit.sc.hp.com!rkarlqu@network.ucsd.edu Subject: Reciprocal mixing at 25 kHz, ICF-2010 Help! To: ham-homebrew@ucsd.edu In article <1994Jan29.071103.1@ntuvax.ntu.ac.sg>, wrote: >Hi, > > I am experiencing reciprocal mixing of signals on my SONY >ICF-2010/2001D at about 24 or 25 kHz above the actual signal image. >Is there something i can do to fix this? Tks. No. ------------------------------ Date: Fri, 28 Jan 1994 14:18:56 GMT From: nntp.ucsb.edu!library.ucla.edu!europa.eng.gtefsd.com!howland.reston.ans.net!torn!govonca!sivyerb@network.ucsd.edu Subject: The World's Smallest Receiver To: ham-homebrew@ucsd.edu Jeff Herman's post about the world's smallest transmitter seems to have stirred up considerable interest. Does anyone have a collection of simple receiver circuits that could be paired with Jeff's transmitters. I would like to build a QRP station but have been away from building things for some time. Maybe we can renew interest in construction projects. Bob -- ******************************************************************************** Bob Sivyer Phone:(519-661-2714) Systems Programmer/Analyst Internet: sivyerb@gov.on.ca West Science and Technology Transfer Unit EPO: sivyerbo@EPO@MHS@EPO Ministry of Natural Resources London, Ontario N6A 4L6 Ham Radio: VA3SI & VE3LDU ******************************************************************************* ------------------------------ End of Ham-Homebrew Digest V94 #16 ****************************** ******************************