Date: Sun, 21 Nov 93 04:30:09 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 #117 To: Ham-Ant Ham-Ant Digest Sun, 21 Nov 93 Volume 93 : Issue 117 Today's Topics: Archery Advice for An ARRL Handbook - HELP! Copper j-pole antenna - where? Helical antenna MFJ Counterpoise ? ? ? Mini-Products Mini-Quad Tower Guy Anchors What is it? 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: 20 Nov 93 17:22:24 GMT From: ogicse!emory!europa.eng.gtefsd.com!library.ucla.edu!agate!iat.holonet.net!pubcon.fort-worth.tx@network.ucsd.edu Subject: Archery Advice for An To: ham-ant@ucsd.edu if you are any good at fishing, a regular fishing pole with a reel and as sinker on the line works nicely also. plus, you have the option of reeling up the line when your finished. b. wb5kxw ------------------------------ Date: Wed, 17 Nov 1993 13:20:25 -0600 From: munnari.oz.au!spool.mu.edu!sol.ctr.columbia.edu!caen!hellgate.utah.edu!cc.usu.edu!sy_j.pgh.wec.com!user@network.ucsd.edu Subject: ARRL Handbook - HELP! To: ham-ant@ucsd.edu In article <2cdevo$6lj@hp-col.col.hp.com>, jms@col.hp.com (Mike Stansberry) wrote: > > Since you're in Colorado Springs, try Centennial Electronics on E. Bijou, > just across the street From Montgomery Wards. > > Mike, K0TER anybody knows a store in the Pittsburgh, PA area ? -- "Beware of bugs in the above code; I have only proved it correct, not tried it." -- Donald Knuth ------------------------------ Date: 16 Nov 1993 16:06:52 GMT From: usc!math.ohio-state.edu!darwin.sura.net!news-feed-2.peachnet.edu!concert!samba.oit.unc.edu!not-for-mail@network.ucsd.edu Subject: Copper j-pole antenna - where? To: ham-ant@ucsd.edu Anyone out there know what issue of 73 had the constructionarticle on a copper j-pole antenna? Thanks. Carty KA2Y cellis@brockvma.cc.brockport.edu -- The opinions expressed are not necessarily those of the University of North Carolina at Chapel Hill, the Campus Office for Information Technology, or the Experimental Bulletin Board Service. internet: laUNChpad.unc.edu or 152.2.22.80 ------------------------------ Date: 17 Nov 1993 18:45:01 GMT From: newsstand.cit.cornell.edu!newsstand.cit.cornell.edu!usenet@cu-arpa.cs.cornell.edu Subject: Helical antenna To: ham-ant@ucsd.edu In article Tony Mantler, tmantler@inqmind.bison.mb.ca writes: >hello all, > I'm planning on building a helical antenna, but I need the >formulas for the measurements. Also some tips on construction methods >would help. > >Thanx The handbook has some information, but the antenna book has more and the satellite experimenters handbook has some other stuff. I read both of the latter and everything else I could lay my hands on, then made up a spreadsheet to allow me to diddle the values (mostly to get round, reasonable dimensions on things like diameter, spacing, etc) and observe the effects on gain and beamwidth. I ended up building a 14 turn RHCP helix that has been doing yeoman duty for 3-4 years now on oscar 13 for me. I used the squashed turn radial match method on mine instead of the 1/4 matching section. Much easier to build and tune and it's flat from 420-450 mhz (and doesn't do too bad on ch14 either). I'd really recommend doing that for the matching. i built mine on two rails of 1x2, with a framework of more 1x2's at the rear to hold a hardware screen reflector. It's a bit heavy but it was easy to construct, cheap, and rugged. The dimensions on mine ended up with a 10 foot boom, 9 inch diameter, 7 inch (I think) turn spacing and 14 turns. Gain was calulated at about 16dbi, and it performs about equal to a KLM 40 cx except you can't switch polarity and it is about 6db heavier and 8 db cheaper. It provides good uplink at 25 watts to AO13. It's also fun on terrestrial communications although you throw away 3db to linear antennas. I use it a fair bit with ATV and it works well there. If you want a copy of my spreadsheet, email me and we'll see if we can figure out a way to exchange it. 73 de Kevin, WB2EMS fkf1@cornell.edu ------------------------------ Date: Fri, 19 Nov 1993 23:54:29 GMT From: netcomsv!netcom.com!greg@decwrl.dec.com Subject: MFJ Counterpoise ? ? ? To: ham-ant@ucsd.edu In article taylorjh@wmvx.dnet.dupont.com (John H. Taylor - K3ZKA) writes: >I operate HF from the second floor of my home with a pair of dipoles >co-fed. Although grounding is poor (non-existent), I am not aware of any >problems with RF in the shack. Nevertheless, I am interested in improving >the RF grounding situation. > >I have seen advertisements for the MFJ counterpoise which is dsigned for >situations such as this. Has anybody had operating experience with the MFJ >counterpoise and what do they think of it? I used it in a similar situation, but more RF-hostile. It really worked well! Greg ------------------------------ Date: Thu, 18 Nov 1993 07:48:37 GMT From: nntp.ucsb.edu!library.ucla.edu!agate!howland.reston.ans.net!cs.utexas.edu!utnut!nott!cunews!freenet.carleton.ca!Freenet.carleton.ca!aj467@network.ucsd.edu Subject: Mini-Products Mini-Quad To: ham-ant@ucsd.edu I'm looking for some help here, does anyone have a manual, or information showing design/construction for this little 6, 10, 15, 20 mtr beam. It is a quagi hybrid with capacitive whiskers and band coils. Please E-Mail to aj467@freenet.carleton.ca -- Bill VE3NJW Advanced Amateur Packet Address : VE3NJW@VE3KYT.#EON.ON.CAN Freenet Address: aj467@Freenet.Carleton.ca ------------------------------ Date: 17 Nov 1993 17:00:38 CST From: ftpbox!mothost!schbbs!maccvm.corp.mot.com!CSLE87@uunet.uu.net Subject: Tower Guy Anchors To: ham-ant@ucsd.edu The reason for tensioning to 10% of rated load is to be sure that the guy on the downwind side of the tower is always in tension. This is related to a mechanical phenomenon not usually explained in statics class- You can't push a rope! Applied to this situation, a loose guy provides absolutely no support to the structure. Warm temperatures will cause the guys to slacken because the guys are longer than the tower is tall, both have (almost) the same temperature coefficient of expansion. This is one more case where tight is better than loose. ------------------------- Original Article ------------------------- Newsgroups: rec.radio.amateur.antenna From: jayk@fc.hp.com (Jay Kesterson K0GU) Subject: Re: Tower Guy Anchors Date: Tue, 16 Nov 1993 16:19:45 GMT Reply-To: jayk@fc.hp.com References: <1993Nov4.162453.10770@ccd.harris.com> <1993Nov5.061202.27862@ke4zv. Nntp-Posting-Host: corona.fc.hp.com Gary Coffman (gary@ke4zv.atl.ga.us) wrote: : If you can get access to a cable tension gauge, set the guy tension to : 50-75 pounds depending on temperature, the tower will "grow" in warm : weather so use the higher tension setting then. The guys will loosen in : cold weather as the tower shrinks. : Gary The Rohn catalog says to tension the guys to 10 percent of their rated value (when using the proper size guys they recommend for various towers). I'm no expert on why, but thats what is says. 73, Jay K0GU jayk@fc.hp.com ------------------------------ Date: 17 Nov 1993 17:08:48 CST From: ftpbox!mothost!schbbs!maccvm.corp.mot.com!CSLE87@uunet.uu.net Subject: What is it? To: ham-ant@ucsd.edu This one sounds like any of a large number of CB base station antennas which were resonant in the 27 MHz range. Claimed gain ranged from 3 to 11 dB, while actual performance is about 2.1 dBi at best, due to poor dielectric and sloppy mechanical construction. ------------------------- Original Article ------------------------- From: johnz@utxvms.cc.utexas.edu Newsgroups: rec.radio.amateur.antenna Subject: What is it? Date: 16 Nov 93 16:42:28 CST I bought an antenna at a garage sale and am not sure what it was designed for. it is a vertical about 19 feet high with three 8 ft counterpoises at the bottom. It has 3 small wires at the top, each about 10in long. What frequency was it designed to operate at? ------------------------------ End of Ham-Ant Digest V93 #117 ****************************** ******************************