Date: Thu, 11 Aug 94 04:30:17 PDT 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 #256 To: Ham-Ant Ham-Ant Digest Thu, 11 Aug 94 Volume 94 : Issue 256 Today's Topics: Ham-Ant Digest V94 #255 -Reply SWR calculation needed.... Wanted: 1-3 Foot parabolic antennas Which telescopic antenna for 2m HT? 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: 11 Aug 94 07:38:58 GMT From: news-mail-gateway@ucsd.edu Subject: Ham-Ant Digest V94 #255 -Reply To: ham-ant@ucsd.edu I'm on vacation until August 22. I'll read your message and reply when I return. If you need assistance with Emission Monitoring or Stack Testing, please contact Jerry Keefe or Jack Harvanek. Thanks Alan Hicks ------------------------------ Date: 10 Aug 1994 22:44:36 +0200 From: ihnp4.ucsd.edu!munnari.oz.au!quagga.ru.ac.za!ee.und.ac.za!ticsa.com!cstatd.cstat.co.za!not-for-mail@network.ucsd.edu Subject: SWR calculation needed.... To: ham-ant@ucsd.edu Greetings to one and all, Can somebody please tell me the formula for calculating SWR when given only the forward and reflected power in watts. i.e Bird Inline reads 15w forward and 6w reverse. SWR=? E-mail to me or posted on this group would be nice. Thanks in advance. Cheerio, Brian ZR5DTS Voice: ++27-31-7011201 (06:00-14:30 UTC) Internet: briane@goofy.iaccess.za Fax: ++27-31-7090813 VHF Packet: ZR5DTS@ZR5GQ.NTL.ZAF ICBM's: 29:51:05 S 30:53:59 E ********************************************************************* I am glad I don't know everything, that way life isn't boring - Brian Ellse 94 ********************************************************************* ------------------------------ Date: Wed, 10 Aug 1994 12:28:26 -0800 From: ihnp4.ucsd.edu!qualcomm.com!kbanke.qualcomm.com!user@network.ucsd.edu Subject: Wanted: 1-3 Foot parabolic antennas To: ham-ant@ucsd.edu The San Diego(Ham Radio) Microwave group is looking for inexpensive aluminum parabolic antennas for some of its members. The main interest is in the 1-3 foot size, with or without feeds. The group is also interested in other microwave parts and pieces from 900 MHz and up. - Kerry N6IZW kbanke@qualcomm.com ------------------------------ Date: Wed, 10 Aug 94 20:07:56 -0500 From: news.delphi.com!usenet@uunet.uu.net Subject: Which telescopic antenna for 2m HT? To: ham-ant@ucsd.edu Vinod Narayanan writes: >The two candidates I found are the AEA "hotrod" and the AEA is the one I use. I don't know if you can hit the reapeaters on 1/2 watt or not. One caution: this thing is not flexible, it can damage the BNC connector if you're not careful. Otherwise, good antenna. ------------------------------ Date: Sun, 7 Aug 1994 06:05:02 GMT From: agate!library.ucla.edu!csulb.edu!csus.edu!netcom.com!wa2ise@ames.arpa To: ham-ant@ucsd.edu References , , <31uiit$ilm@agate.berkeley.edu>du Subject : Re: JPole fundamentals In article <31uiit$ilm@agate.berkeley.edu> kennish@kabuki.EECS.Berkeley.EDU (Ken A. Nishimura) writes: >In article , >David Bashaw wrote: >>Actually, I thought a J looked electrically like: > >> ______________________ >> |______ >>One continuous electrical (D.C.) short :>) > >>And a Zep like this: > > >> 1/4 wave >> ______ >> _________________________ >> >> >>J's and Zeps, two different kinds of antennas? Am I wrong? > >They are really the same thing. The ends of a 1/2 wave end-fed antenna >are at a high impedance. Going back a 1/4 wave on the transmission line >makes it look like a short. So putting a short there really doesn't >make a difference. Or perhaps more clearly, a shorted 1/4 wave >stub looks like an open at the other (unshorted) end, so it won't affect the >operation of the 1/2 wave section. Where you attach the coax determines >your feedpoint impedance. > Found an ancient book on antennas "TV and other Recieving Antennas" 1950, and it has several simple diagrams of antennas, on a ""J" antenna or Zepp". Drawing shows a long vertical rod, and a shorter element next to it an inch away parallel. Diagram shows the shorter element is just the coax center conductor extended 1/4 wavelength up. and the diagram unclearly shows the coax cable "ty-rap-ed or taped to the long rod, not clear if the coax shield is electrically connected or not. No shorted end or tap in evidence. Book says 50 ohm impedance. | \ | \ | active antenna | / || || |# top of coax, shorter element connected to center conductor, |# shield connection not clear if it is or not connected to long rod # # coax ------------------------------ End of Ham-Ant Digest V94 #256 ******************************