Date: Mon, 6 Dec 93 04:30:21 PST From: Ham-Ant Mailing List and Newsgroup Errors-To: Ham-Ant-Errors@UCSD.Edu Reply-To: Ham-Ant@UCSD.Edu Precedence: Bulk Subject: Ham-Ant Digest V93 #134 To: Ham-Ant Ham-Ant Digest Mon, 6 Dec 93 Volume 93 : Issue 134 Today's Topics: 50 ohm coax to 75 ohm coax transformer (2 msgs) electrical codes First antenna for 160 meters Phone No. for Andrew Cable wanted. Rugged 2 meter antenn (2 msgs) What is a beverage antenna? (2 msgs) 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-Ant Digest are available (by FTP only) from UCSD.Edu in directory "mailarchives/ham-ant". 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: Thu, 2 Dec 1993 17:01:24 GMT From: elroy.jpl.nasa.gov!usc!howland.reston.ans.net!usenet.ins.cwru.edu!news.ecn.bgu.edu!willis1.cis.uab.edu!spam.dom.uab.edu!user@ames.arpa Subject: 50 ohm coax to 75 ohm coax transformer To: ham-ant@ucsd.edu > Michael A Cecere (mac20@namaste.cc.columbia.edu) wrote: > : oh yeah, at 900MHz. would this be terribly complicated to homebrew? > > : I want to go from f-type connector 75-ohm "cable" coax to, get this, > : 9913 N-type coax. (the section of 75 ohm is just to match to the transceiver, > : the 9913 has to run over 100') An alternative for long runs for low loss is to go to twin lead, using a 4:1 balun and a quarter wave impedence matching twin lead. I recognize this is something completely different, and may not work at all in tha appliction. I used such a system for feeding an antenna suspended from a balloon 200 feet up and it worked nicely. The impedence matching section of twin lead was made of two pieces of 1/4 inch OD copper tubing held one inch apart on center. The 4:1 balun transformed the impedence from 50 to 200 ohm, and the quarter wave transformer matched 200 to 300 ohms. The graph of impedence vs. wire spacing is in the ARRL handbook. Steve Holland ------------------------------ Date: Thu, 2 Dec 1993 17:04:50 GMT From: nntp.ucsb.edu!library.ucla.edu!agate!howland.reston.ans.net!usenet.ins.cwru.edu!news.ecn.bgu.edu!willis1.cis.uab.edu!spam.dom.uab.edu!user@network.ucsd.edu Subject: 50 ohm coax to 75 ohm coax transformer To: ham-ant@ucsd.edu > Michael A Cecere (mac20@namaste.cc.columbia.edu) wrote: > : oh yeah, at 900MHz. would this be terribly complicated to homebrew? > > : I want to go from f-type connector 75-ohm "cable" coax to, get this, > : 9913 N-type coax. (the section of 75 ohm is just to match to the transceiver, > : the 9913 has to run over 100') Another thought is to go from 50 ohm coax to a 4:1 quarter wave balun to 200 ohm, connect to a quarter wave section of 1/4 inch copper tubing spaced 1 inch center to center, which will bring you to 300 ohms, then through another 4:1 quarter wave balun to 75 ohm. Steve Holland ------------------------------ Date: Sat, 4 Dec 1993 06:28:38 GMT From: mvb.saic.com!unogate!news.service.uci.edu!usc!math.ohio-state.edu!darwin.sura.net!spool.mu.edu!agate!iat.holonet.net!pubcon!brian.oakley@network.ucsd.edu Subject: electrical codes To: ham-ant@ucsd.edu hi, tom. i used to work as an electrician and from what i understood was that all local codes had to AT LEAST meet nec codes, but can exceed them with extra requirements if deemed necessary. ive been out of the business for about 8 years so it could have changed since then. someone enlighten me please. 73 brian. wb5kxw ------------------------------ Date: 2 Dec 1993 17:06:44 GMT From: nntp.ucsb.edu!library.ucla.edu!agate!howland.reston.ans.net!pipex!uknet!doc.ic.ac.uk!bright.ecs.soton.ac.uk!pdh@network.ucsd.edu Subject: First antenna for 160 meters To: ham-ant@ucsd.edu I realise this isn't one bit helpful but ;^) My first 160m antenna was an indoor dipole. (honest!) -- Peter Harris G4BDQ | Unusual exploding disclaimer -> (}|){//) Fibre Optics *-----------------------------------------------------(--PAF !-) Southampton University| "Get those feet dancin'" (/}|{\\) pdh@ecs.soton.ac.uk | Geoffrey Boycott ||| ------------------------------ Date: 3 Dec 1993 10:07:55 CST From: ftpbox!mothost!schbbs!maccvm.corp.mot.com!CSLE87@uunet.uu.net Subject: Phone No. for Andrew Cable wanted. To: ham-ant@ucsd.edu The phone numbers for Andrew are 1-800-255-1479 or 708-349-3300 ------------------------------ Date: Sun, 5 Dec 1993 10:10:08 GMT From: mentor.cc.purdue.edu!sage.cc.purdue.edu!blumb@purdue.edu Subject: Rugged 2 meter antenn To: ham-ant@ucsd.edu In article <931204075944230@pubcon.fort-worth.tx.us> brian.oakley@pubcon.fort-worth.tx.us (BRIAN OAKLEY) writes: >anyone ever uses a mag mount 5/8 wave 2 meter whip stuck on a bike book >rack? looks like this would work ok. i have not tried this yet but >seems a simple way to put an antenna on a bicycle. 73 wb5kxw It'll work ok, if you don't mind a little RF danger. -- Bill Blum N9VLS blumb@sage.cc.purdue.edu Purdue University, W. Lafayette, IN Reality is for those who can't handle subscribing to IASFM and Model Railroader ------------------------------ Date: Sat, 4 Dec 1993 06:19:29 GMT From: mvb.saic.com!unogate!news.service.uci.edu!usc!howland.reston.ans.net!agate!iat.holonet.net!pubcon!brian.oakley@network.ucsd.edu Subject: Rugged 2 meter antenn To: ham-ant@ucsd.edu anyone ever uses a mag mount 5/8 wave 2 meter whip stuck on a bike book rack? looks like this would work ok. i have not tried this yet but seems a simple way to put an antenna on a bicycle. 73 wb5kxw ------------------------------ Date: 6 Dec 93 00:02:38 GMT From: ogicse!emory!kd4nc!ke4zv!gary@network.ucsd.edu Subject: What is a beverage antenna? To: ham-ant@ucsd.edu In article <1993Dec2.192459.20436@dale.ksc.nasa.gov> rsumperl@dale.ksc.nasa.gov (Ray Sumperl) writes: > Can someone please post or email me what a beverage antenna is? The Beverage is of a class of antennas called travelling wave antennas. It's primarily a receiving antenna for use at MW frequencies. It's normally very long, 8-10 wavelengths, mounted close to the ground, about 2 meters, and terminated at the far end in a resistance, typically 500-1000 ohms depending on ground conductivity. It is directional in the direction toward the termination, and it favors low angle radiation. It depends on the proximity to fairly poorly conductive soil to achieve the wave bending needed for it's travelling wave action. It has excellent suppression of high angle radiation, off axis radiation, and atmospheric and manmade noise. Gary -- Gary Coffman KE4ZV | Where my job's going, | gatech!wa4mei!ke4zv!gary Destructive Testing Systems | I don't know. It might | uunet!rsiatl!ke4zv!gary 534 Shannon Way | wind up in Mexico. | emory!kd4nc!ke4zv!gary Lawrenceville, GA 30244 | -NAFTA Blues | ------------------------------ Date: Thu, 2 Dec 1993 19:24:59 GMT From: dale.ksc.nasa.gov!rsumperl@ames.arpa Subject: What is a beverage antenna? To: ham-ant@ucsd.edu Greetings all... Can someone please post or email me what a beverage antenna is? Thanks, Ray ------------------------------ Date: Thu, 02 Dec 1993 20:30:26 GMT From: mustang.mst6.lanl.gov!nntp-server.caltech.edu!news.claremont.edu!paris.ics.uci.edu!csulb.edu!library.ucla.edu!agate!usenet.ins.cwru.edu!magnus.acs.ohio-state.edu!csn!yuma!@@nntp.ucsb.edu To: ham-ant@ucsd.edu References <1993Dec2.012544.22087@news.unr.edu>, <1993Dec2.150441.24957@news.cs.tut.fi>, <2dl7b4$5oh@bright.ecs.soton.ac.uk>du Subject : Re: First antenna for 160 meters(continuously loaded???) I've thought about a continuously loaded (read: slinky style) vertical or possibly a cont loaded dipole for 160. The dipole version could be made small enough to rotate! Has anyone done something like this beyond the sparse articles in ARRL literature???? Just wondering, Galen, KF0YJ ------------------------------ End of Ham-Ant Digest V93 #134 ****************************** ******************************