Date: Thu, 3 Feb 94 04:30:19 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 V94 #22 To: Ham-Ant Ham-Ant Digest Thu, 3 Feb 94 Volume 94 : Issue 22 Today's Topics: 60' sloper Antenna pre-amps. Are MFJ Antennas Any Good? Biconical Antenna Design BV2CH Dipole supplies (3 msgs) How far wire antenna from power lines (2 msgs) Ideas ? GAP Challenger DX-VI mininec source code new Radio Communications mailing list Quagi part 2 RG-58 and Discone ant. problem at VHF RS Rotor (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: 31 Jan 94 20:14:00 -0500 From: blkcat!1-109-239-0!Paul.Brzonkala@uunet.uu.net Subject: 60' sloper To: ham-ant@ucsd.edu for sale with two baluns. 50' coax.... (703) 816-7823. $45.00 ------------------------------ Date: Sun, 30 Jan 1994 16:11:34 GMT From: agate!howland.reston.ans.net!newsserver.jvnc.net!raffles.technet.sg!ntuix!ntuvax.ntu.ac.sg!asirene@network.ucsd.edu Subject: Antenna pre-amps. To: ham-ant@ucsd.edu In article , dtiller@cscsun.rmc.edu (Dave Tiller) writes: > asirene@ntuvax.ntu.ac.sg wrote: > : Hi, > > : Can anyone tell me the disadvantages/advantages of using an antenna > : pre-amp? > > Advantages: Better apparent noise figure since the coax attenuation is > no longer a factor (for antenna mounted amps), much higher signal levels, > inproved copy on waek signals. What about for non-masthead pre-amps? Got any good circuits? 73 de 9V Daniel > > Disadvantages: Your transmitter output must backwash thru the thing - either > the amp itself must detect the inbound RF and switch itself away, or you > must provide a switching relay and the appropriate signal to do it manually. > Additional risk of lightning damage since you've got to run power up the > coax or a separate cable, and now there's a sensitive little GasFET up there > waiting for a strike. Greater chance of front end overload on relatively > strong signals (not an issue with an RF gain control.) > > -- > David Tiller | Network Administrator | Voice: (804) 752-7373 | > dtiller@rmc.edu | Randolph-Macon College| Fax: (804) 752-7231 | > n2kau@wa4ong.va.usa.na | P.O. Box 5005 | This space for rent. | > ICBM: 37 45N 77 45W | Ashland, Va 23005 | | ------------------------------ Date: 31 Jan 94 12:03:10 -0800 From: library.ucla.edu!csulb.edu!nic-nac.CSU.net!nic.csu.net!vax.sonoma.edu!butler@network.ucsd.edu Subject: Are MFJ Antennas Any Good? To: ham-ant@ucsd.edu I'm considering ordering a couple antennas from MFJ - specifically the 5/8 2m base (1750) and the 5/8 2m moblie (1728). I'd like to hear about any experiences, comments, or suggestions that might help make my decision. Thanks, -Bob Butler, KE6EHO (butler@sonoma.edu) ------------------------------ Date: Sun, 30 Jan 1994 04:42:50 GMT From: agate!library.ucla.edu!csulb.edu!nic-nac.CSU.net!usc!cs.utexas.edu!geraldo.cc.utexas.edu!slip-2-5.ots.utexas.edu!rfsimon@network.ucsd.edu Subject: Biconical Antenna Design To: ham-ant@ucsd.edu Does anyone have info on design parameters for a biconical antenna for use on 30 to 88 Mhz for both transmit and receive? I have heard that this type of antenna acn maintain a reasonable SWR over several octaves of bandwidth. Maybe someone with military commo experience can help. The design needs to be similar to a DOD OE-254 antenna. Thanks. ------------------------------ Date: Tue, 1 Feb 1994 23:09:56 GMT From: ucsnews!sol.ctr.columbia.edu!howland.reston.ans.net!cs.utexas.edu!oakhill!victorc@network.ucsd.edu Subject: BV2CH To: ham-ant@ucsd.edu This is a testing from BV2CH. ------------------------------ Date: Sun, 30 Jan 1994 15:06:13 GMT From: world!dts@decwrl.dec.com Subject: Dipole supplies To: ham-ant@ucsd.edu In article <2ige7m$eij@charm.magnus.acs.ohio-state.edu> wvanhorn@magnus.acs.ohio-state.edu (William E Van Horne) writes: > > > >Julian Macassey wrote: > >> And finally the $64,000.00 question. What is recommended as >>the best "rope" to hold up my cheesy antennas? It should be rot and UV >>proof. Nylon I believe will rot in the sun, as will polyester. What is >>the definative word? Any Plastics men on the net who can answer this? > >ANY organic material (plastics, hemp, human skin :-) ) is damaged by >UV. Plastics can be doped with "UV retardant" additives, but that only >slows down the deterioration, it doesn't stop it. The best "UV >retardant" of all is carbon-black, a pigment that totally absorbs all >light of all wavelengths. All black plastic (I think) is loaded with >carbon-black pigment, so that is the key. > >One source of black polyester rope is Synthetic Textiles, Inc., 2472 >Eastman Avenue, Bldg 21-22, Ventura, CA 93003, (805) 658-7903. I have >never dealt with them, but received their literature. For myself, I use >plain nylon rope and replace it every couple of years. I have two spools of dacron line from Synthetic Textiles. The product is great, and the service was very good. Be sure to cut the rope with a hot knife (effectively melting it) rather than cutting. This keeps the ends sealed (same rule applies to any synthetic rope like nylon, etc.). -- --------------------------------------------------------------- Daniel Senie Internet: dts@world.std.com Daniel Senie Consulting n1jeb@world.std.com 508-365-5352 Compuserve: 74176,1347 ------------------------------ Date: Mon, 31 Jan 1994 13:45:33 GMT From: netcomsv!netcom.com!greg@decwrl.dec.com Subject: Dipole supplies To: ham-ant@ucsd.edu >One source of black polyester rope is Synthetic Textiles, Inc., 2472 >Eastman Avenue, Bldg 21-22, Ventura, CA 93003, (805) 658-7903. Another is Home Depot or practically any other hardware store. Greg ------------------------------ Date: Mon, 31 Jan 1994 13:42:08 GMT From: netcomsv!netcom.com!greg@decwrl.dec.com Subject: Dipole supplies To: ham-ant@ucsd.edu In article <1994Jan28.201536.11492@bongo.tele.com> julian@bongo.tele.com (Julian Macassey) writes: > > And finally the $64,000.00 question. What is recommended as >the best "rope" to hold up my cheesy antennas? It should be rot and UV >proof. Nylon I believe will rot in the sun, as will polyester. What is >the definative word? Any Plastics men on the net who can answer this? It may not be definitive, but among the riggers who work on tall ships the ONLY type of line which they will trust with their lives is the black polypropylene (often with an orange stripe) which truckers use to secure their loads. If this line 'looks' good it generally *is* good. This is in marked contrast to other types, which can look great but fail abruptly under load, once exposed to the rigors of the atmosphere. Greg ------------------------------ Date: 1 Feb 1994 15:19:57 GMT From: mvb.saic.com!unogate!news.service.uci.edu!usc!howland.reston.ans.net!vixen.cso.uiuc.edu!ux2.cso.uiuc.edu!ignacy@network.ucsd.edu Subject: How far wire antenna from power lines To: ham-ant@ucsd.edu Do any regulations exists that tell how far away the wire antenna should be from the power lines? I know that the proximity results in line noise, so it is best to keep it as far away as possible. Ignacy Misztal, NO9E ignacy@uiuc.edu ------------------------------ Date: Tue, 1 Feb 1994 20:32:19 GMT From: ucsnews!sol.ctr.columbia.edu!howland.reston.ans.net!usenet.ins.cwru.edu!agate!library.ucla.edu!csulb.edu!nic-nac.CSU.net!usc!elroy.jpl.nasa.gov!newncar!csn!col.hp.com!srgenprp!alanb@@. Subject: How far wire antenna from power lines To: ham-ant@ucsd.edu Ignacy Misztal (ignacy@ux2.cso.uiuc.edu) wrote: : Do any regulations exists that tell how far away the wire antenna should be : from the power lines? I know that the proximity results in line noise, : so it is best to keep it as far away as possible. You should call up your local Planning Department to get the scoop on zoning regulations. As far as safety goes, be sure that there is no way the antenna could ever fall on the power lines, or that the power lines could ever fall on the antenna. AL N1AL ------------------------------ Date: Tue, 1 Feb 1994 15:50:40 +0000 From: ucsnews!sol.ctr.columbia.edu!howland.reston.ans.net!pipex!demon!dis.demon.co.uk!paddocks.demon.co.uk!andrew@network.ucsd.edu Subject: Ideas ? GAP Challenger DX-VI To: ham-ant@ucsd.edu Does anyone have any ideas please ? I installed a GAP Challenger DX-VI antenna in the summer of 92 and it has worked reasonably well up to a few months ago. Although the match is still about the same and it still hears pretty well I seem to be getting very poor reports (if reports at all). Friends using other verticals aroud this location seem to get through to the stations I am calling but not me ! I've had the antenna down and checked connections but nothing seems to help. Any ideas ? Has anyone actually tried an A/B comparrison with the GAP and an R7, HF6V or AP8 ? I feel ready to junk the GAP and try something else. -- +-------------------------------+------------------------------------------+ | Andrew Gawthrope G0RVM | internet : andrew@paddocks.demon.co.uk | | | compuserve : 100113,3062 | +-------------------------------+------------------------------------------+ ------------------------------ Date: 31 Jan 1994 19:55:23 GMT From: library.ucla.edu!europa.eng.gtefsd.com!howland.reston.ans.net!noc.near.net!sunfish.hi.com!brainiac.hi.com!user@network.ucsd.edu Subject: mininec source code To: ham-ant@ucsd.edu I found the source for mininec in the /pub/rander/NEC directory on netcom.com. Thanks to Ray Anderson WB6TPU for maintaining this site. Steve Byan internet: steve@hicomb.hi.com Hitachi Computer Products (America), Inc. 1601 Trapelo Road phone: (617) 890-0444 Waltham, MA 02154 FAX: (617) 890-4998 ------------------------------ Date: Wed, 2 Feb 1994 23:15:48 GMT From: dog.ee.lbl.gov!newshub.nosc.mil!news!martinb@network.ucsd.edu Subject: new Radio Communications mailing list To: ham-ant@ucsd.edu NRaD RADIO COMMUNICATIONS NETWORK We are beginning a new mailing list for the professional radio communications engineering community. rec.radio.amateur.* is a well established source of information for radio hobbyists, but it does not meet the needs of many commercial, military, and academic professionals. Therefore, we are hoping that this mailing list will somewhat fulfill this need. Relevant topics include: radio propagation, antenna design, hardware design, FCC regulations, industry trends, parts suppliers, military requirements, and so forth. We would prefer that hobby-oriented topics remain on the established newsgroups. To subscribe, send a message to me at: martinb@cod.nosc.mil I will add your name to the list and send you an informational message about the operation of the mailing list. If you wish to unsubscribe, send me a message, and I will remove your name from the mailing list. Brett F. Martin Naval Command, Control, and Ocean Surveillance Center Research, Development, Test, and Evaluation Division (NRaD) San Diego CA . ------------------------------ Date: 2 Feb 94 21:19:48 GMT From: news-mail-gateway@ucsd.edu Subject: Quagi part 2 To: ham-ant@ucsd.edu I left one out :) Center Frequency 432.000 # of Elements 15 Units are Cm Length Spacing Boom Pos Reflector 71.120 0.000 0.000 Driven Ele 67.628 17.780 17.780 Director # 1 29.845 13.335 31.115 Director # 2 29.686 27.940 59.055 Director # 3 29.528 14.859 73.914 Director # 4 29.369 22.225 96.139 Director # 5 29.210 22.225 118.364 Director # 6 29.051 22.225 140.589 Director # 7 28.892 30.480 171.069 Director # 8 28.734 30.480 201.549 Director # 9 28.734 28.575 230.124 Director # 10 28.575 29.210 259.334 Director # 11 28.416 23.336 282.670 Director # 12 28.257 31.432 314.103 Director # 13 28.099 34.925 349.028 Total Length 3.490 M end the views expressed here are the author's C. Harper harper@huntsville.sparta.com or kd4qio@amsat.org KD4QIO SPARTA Inc (205) 837-5282 x1216 voicemail 4901 Corporate Drive (205) 830-0287 FAX Huntsville AL 35805 "we have met the enemy and he is us." w. kelly ------------------------------ Date: Tue, 1 Feb 1994 17:00:28 GMT From: mvb.saic.com!unogate!news.service.uci.edu!usc!howland.reston.ans.net!spool.mu.edu!news.nd.edu!news1.oakland.edu!rcsuna.gmr.com!kocrsv01!c2xjcb@network.ucsd.edu Subject: RG-58 and Discone ant. problem at VHF To: ham-ant@ucsd.edu > > Also, don't rule out the possibility of front-end overload on the scanner > when the discone is connected. There may be nearby transmitter(s) that > will cause the scanner's front-end to overload, therefore dsensitizing > it. The problem doesn't take place with the rubber duck due to the > decrease in signal strength. > > My $0.02 worth, > Keith Wolford > N9IXG > c22kw@kocrsv01.delcoelect.com Might a test for this be to place an attenuator box between the rig and the discone, set the attenuator on "0dB", and then slowly increase the attenuation and see if at some point the signals magically become LOUDER, even though you are increasing attenuation? i.e. At some point you will have attenuated the "loud" nearby transmitter to the point where it doesn't saturate the front-end and lets the desired signal thru? I suppose if you know what the theoretical dB difference between the duckie and the discone was, this might be a good upper limit on the attenuation levels you want to try. -- James C. Bach Ph: (317)-451-0455 The views & opinions expressed Advanced Project Engr. GM-NET: 8-322-0455 herein are mine alone, and are Powertrain Strategy Grp Amateur Radio: WY9F NOT endorsed, sponsored, nor Delco Electronics Corp. Just say NO to UNIX! encouraged by DE or GM. ------------------------------ Date: Tue, 1 Feb 1994 22:13:01 GMT From: library.ucla.edu!europa.eng.gtefsd.com!howland.reston.ans.net!usenet.ins.cwru.edu!news.csuohio.edu!vmcms.csuohio.edu!R0264@network.ucsd.edu Subject: RS Rotor To: ham-ant@ucsd.edu In article <2iegoo$7v@hopper.acm.org> smithson@ACM.ORG writes: > >Does anyone have any experience with Radio Shack antenna rotors? I can find >smithson@acm.org I use one for a Cushcraft ten-3, 10m beam. I have a homebrew thrust bearing several feet above it, made of an old mast-through rotor with the innards removed. It works ok, but I ruined 2, getting exchanges from RS, before I found out that they can not be used continuous duty. I ruined one, with no load, indoors, brand new, just rotating it back and forth steadily for about 20 minutes. The motor in the control box got too hot and the coil shorted I think. You can look up the weight and wind loading of the Ten-3 in the standard catalogs. Now I'm careful to give it a few seconds rest in swinging back and forth very far. -------- Phil Emerson, AA8JO ------------------------------ Date: Mon, 31 Jan 1994 13:43:39 GMT From: netcomsv!netcom.com!greg@decwrl.dec.com Subject: RS Rotor To: ham-ant@ucsd.edu In article <2iegoo$7v@hopper.acm.org> smithson@ACM.ORG writes: >Does anyone have any experience with Radio Shack antenna rotors? I can find >no information about load capacity for weight or wind-area of antennas, etc. >I'm looking for a rotor for a 14 ele 2m beam I plan to build, and wondered >if the RS offering might do. >Thanks for your help! Find a TV antenna at RS that has similar boom and element dimensions to your beam. Find out what rotor they recommend for that. Buy it. Greg ------------------------------ Date: 1 Feb 1994 17:49:21 +1100 From: unogate!news.service.uci.edu!usc!howland.reston.ans.net!agate!msuinfo!harbinger.cc.monash.edu.au!yarrina.connect.com.au!werple.apana.org.au!lsupoz.apana.org.au!sleeper!orb.@mvb.saic.com To: ham-ant@ucsd.edu References , <2hio5sINN5uu@orb.apana.org.au>, yarrina Subject : Re: safety of HT antennas In matthew@sleeper.apana.org.au (Matthew Geier) writes: >>Yes, I did think of this solution, although for mobile use when I'm on >>a train it would not be so good since the antenna would always be >>collecting bits of tree or tunnel or bridge or...... > Or 1.5KDC railway overhead.. Yes, that's the major problem. I doubt that the transmitter isolation would stand up to 1500 volts DC being fed into it, and the received would very definitely become plastic charcoal! > Id go to the ocupational health and safety officer and present a case >that useing these hand-helds in the cab next to ones head is a potential >health risk, and that roof mounted attenna's should be fitted to all >locomotives, and not just the select few that run interstate. > Then you reduce the close emmissions to the times your are outside checking >things. This could be worthwhile pursuing, but of course with the new radio system being progressively installed any action would be non-resultant. > Not the best, but at least you have removed the situation where you are >in a metal box, holding the annenna next to your head, with the RF bounceing >around untill it finds a window.. Yeah - it's kind of like sitting in a microwave, except that the RF is at UHF and not SHF. I never understood how these so-called communications engineers worked out that we'd be able to get a decent ammount of RF outside of the metalwork of the loco cabs. Most of the time when we're on the older engines (hood units) the only way to get good signal levels in and out is to stand outside on the walkway with the radio! Craig, the Freight Raver. -- Craig Dewick [Freight Raver Craig] (craig@orb.apana.org.au). - Swimming in the MUSIQUARIUM of Life - Always striving for a secure long-term future in an insecure short-term world. ------------------------------ End of Ham-Ant Digest V94 #22 ****************************** ******************************