Date: Sat, 26 Feb 94 04:30:12 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 #48 To: Ham-Ant Ham-Ant Digest Sat, 26 Feb 94 Volume 94 : Issue 48 Today's Topics: 160 M on G5RV A crazy antenna A question (2 msgs) Design of Yagi Antenna Simple Signal Question 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: Fri, 25 Feb 1994 03:43:41 GMT From: unogate!news.service.uci.edu!usc!elroy.jpl.nasa.gov!swrinde!cs.utexas.edu!howland.reston.ans.net!europa.eng.gtefsd.com!news.msfc.nasa.gov!sol.ctr.columbia.edu!newsxfer.itd@mvb.saic.com Subject: 160 M on G5RV To: ham-ant@ucsd.edu regular Keywords: G5RV Has anyone figured out how much wire you need to add to a regular G5RV to tune it to 160 M? Mine is 102' with the 30' of 450 ohm ladder line and I normally run it on 75 and 40 M through a MFJ-949D tuner. I've thought of putting up a dipole for 160 but thought that someone may have done some testing with the addition to a normal G5RV and maybe(?) not experienced much difference on other bands while accessing 160. I suspect that the answer is the addition of something over 60' on each end to get it to tune. Thanks in advance. -- 73 de Ed Engel N7UQZ Internet: eengel@eskimo.com ------------------------------ Date: Fri, 25 Feb 1994 15:34:12 GMT From: mvb.saic.com!unogate!news.service.uci.edu!usc!howland.reston.ans.net!europa.eng.gtefsd.com!library.ucla.edu!csulb.edu!csus.edu!netcom.com!netcomsv!bongo!julian@network.ucsd.edu Subject: A crazy antenna To: ham-ant@ucsd.edu In article <2kkj4d$1fd@cismsun.univ-lyon1.fr> elendir@enst.fr (Elendir) writes: > It's just an attempt to design an antenna which would receive all >polarizations This type of antenna os called "Circularly polarised". There are several designs around. -- Julian Macassey, N6ARE julian@bongo.tele.com Voice: (310) 659-3366 Paper Mail: Apt 225, 975 Hancock Ave, West Hollywood, California 90069-4074 ------------------------------ Date: Fri, 25 Feb 1994 15:34:18 GMT From: mvb.saic.com!unogate!news.service.uci.edu!usc!elroy.jpl.nasa.gov!swrinde!emory!rsiatl!ke4zv!gary@network.ucsd.edu Subject: A question To: ham-ant@ucsd.edu In article <2kj3e1$eb0@master.cs.rose-hulman.edu> derry@NeXTwork.Rose-Hulman.Edu (John Derry) writes: >If I am given two choices as follows on some inexpensive coax at a hamfest >fleamarket which do I buyY > >The cables are identical in every way, same markings, price, length, etc. > >At 144 MHz, when I measure the SWR with an accurate SWR meter one cable >gives a SWR = 10 and the other gives SWR = 6. (SWR being measured at one >end and the other end open (Or shorted.) > >Which cable should I buy? That's a softball question. Obviously buy the one with the higher SWR. For the reasons, search the archives for my treatise entitled "SWR is your friend". Gary -- Gary Coffman KE4ZV | You make it, | gatech!wa4mei!ke4zv!gary Destructive Testing Systems | we break it. | uunet!rsiatl!ke4zv!gary 534 Shannon Way | Guaranteed! | emory!kd4nc!ke4zv!gary Lawrenceville, GA 30244 | | ------------------------------ Date: Fri, 25 Feb 1994 19:01:11 GMT From: mvb.saic.com!unogate!news.service.uci.edu!usc!elroy.jpl.nasa.gov!sdd.hp.com!hp-cv!hp-pcd!hpcvsnz!tomb@network.ucsd.edu Subject: A question To: ham-ant@ucsd.edu John Derry (derry@NeXTwork.Rose-Hulman.Edu) wrote: : If I am given two choices as follows on some inexpensive coax at a hamfest : fleamarket which do I buyY : The cables are identical in every way, same markings, price, length, etc. : At 144 MHz, when I measure the SWR with an accurate SWR meter one cable : gives a SWR = 10 and the other gives SWR = 6. (SWR being measured at one : end and the other end open (Or shorted.) : Which cable should I buy? The higher SWR indicates lower loss: more of the reflected wave made it all the way back to be measured by the SWR meter. _IF_ the SWR meter is calibrated for use with the impedance that the line is, then you can fairly easily calculate the line loss from the measured SWR. ------------------------------ Date: Fri, 25 Feb 1994 15:36:23 GMT From: mvb.saic.com!unogate!news.service.uci.edu!usc!howland.reston.ans.net!europa.eng.gtefsd.com!library.ucla.edu!csulb.edu!csus.edu!netcom.com!netcomsv!bongo!julian@network.ucsd.edu Subject: Design of Yagi Antenna To: ham-ant@ucsd.edu In article <2kktk7$hj2@hippo.shef.ac.uk> el931393@sunc.sheffield.ac.uk (C H Teo) writes: > >I'd like some information about designing Yagi antennas. >It will be appreciated if you could send me a post on the >subject or direct me to FTP sites which holds info/FAQs >etc. Besides the excellent handbooks produced by the ARRL and RSGB, there are also many books on on antennas, some exclusively about Yagis available. -- Julian Macassey, N6ARE julian@bongo.tele.com Voice: (310) 659-3366 Paper Mail: Apt 225, 975 Hancock Ave, West Hollywood, California 90069-4074 ------------------------------ Date: 25 Feb 1994 16:58:32 GMT From: mvb.saic.com!unogate!news.service.uci.edu!usc!elroy.jpl.nasa.gov!news.aero.org!Aero.org!cantrell@network.ucsd.edu Subject: Simple Signal Question To: ham-ant@ucsd.edu In article <2kk57u$rt9@sugar.NeoSoft.COM>, dlc@sugar.NeoSoft.COM (Dane L. Cantwell) writes: |> |> A friend and I were talking about cellular phones. He is in the market |> for one and we were talking about the merits of a "full size" phone at 3 |> watts versus a portable at 0.6 watts. It was my point that the extra |> transmission power is discounted because the signal received at tower is |> related to the square of the distance to the tower.... therefore you |> don't get anything like 5 times the range with a 3 watt model over a 0.6 |> watt unit. Is this right in theory? How about the real world? |> |> I realize that the assumption I am making assumes a point source that |> would radiate in all directions. How close is this assumption to the |> real world antennas? Comments please. |> |> Dane Cantwell - dlc@neosoft.com |> Petroleum Engineer |> |> Seeing as how you have such a great name, I couldn't help but throw in my two cents :-) Another thing to think about is that, with most systems today, the cell receiving antenna sends commands to change the output power of the phone. That is, the base antenna will issue commands to step down (or up) the output power of the phone so that the minimum power necessary for the connection is used. Great, you say, I will just wire up my phone so that it ALWAYS blasts out the 3 watts regardless of what anybody says. Unfortunately, most systems recognize this and, if you don't do as they say, the system will just cut you off. Having the higher power unit might be worthwhile if he is going to spend a lot of time in fringe coverage areas, but if the area he will use is well 'celled' he should probably put his money in a better antenna. So much for my comments. Yours, cantrell ------------------------------ End of Ham-Ant Digest V94 #48 ****************************** ******************************