Date: Mon, 7 Feb 94 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 V94 #25 To: Ham-Ant Ham-Ant Digest Mon, 7 Feb 94 Volume 94 : Issue 25 Today's Topics: ??using HF moible ant. for home base station? J-Pole Design Needed Short Yagi TEMPEST - Electronic Eavesdropping 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: Sun, 6 Feb 1994 20:01:39 GMT From: agate!library.ucla.edu!news.ucdavis.edu!chip.ucdavis.edu!szhall@network.ucsd.edu Subject: ??using HF moible ant. for home base station? To: ham-ant@ucsd.edu I am getting a HF mobile(HUSTLER 10-40 Meters) next for my car and I would like some feeling about using it for a home base ant. as well. I am using a dipole right now..Would it be hard to ground and whats its Db ? please fill me in any imformation you can give me..tns..Jeff N6MYF ------------------------------ Date: 3 Feb 1994 20:13:30 GMT From: usenet.coe.montana.edu!news.uoregon.edu!gaia.ucs.orst.edu!ucs.orst.edu!steinr@decwrl.dec.com Subject: J-Pole Design Needed To: ham-ant@ucsd.edu In article <19940130.10394523.darrylb@delphi.com> DARRYLB@delphi.com writes: >I am looking for a j-pole design using only coax. I am sure I saw such a >design in a recent magazine, but I can't find it now. I'm looking for >something that can be rolled up and easily stored for travel. Though it is not made only of just coax, I highly recommend using a twin-lead TV antenna J-Pole design. I will describe briefly how it is made: Starting at the bottom, short the two leads together. Cut a section of about 55 inches total for the antenna. From the short up to 1.25 inches, connect your standard 50 ohm coax. On one side only up 16.5 inches from short, cut a .25 inch chunck out. It's done! Trim the top for desired SWR. Good luck! --Ray Stein ------------------------------ Date: 6 Feb 1994 18:12:27 GMT From: agate!howland.reston.ans.net!pipex!sunic!ugle.unit.no!lise.unit.no!kenneth@network.ucsd.edu Subject: Short Yagi To: ham-ant@ucsd.edu Due to limited space i'm not able to raise a full size Yagi. Therefore I intend to build a short 2 el. yagi with loading coils for 20 m phone band. Does anyone out there have the dimensions for this antenna ?? What about the gain, F/B-ratio ? what about the performance compared to a X-beam - is there a big difference ??? thanks in advance kenneth, LA7GIA. ------------------------------ Date: 6 Feb 1994 21:19:37 -0500 From: agate!spool.mu.edu!sol.ctr.columbia.edu!usc!yeshua.marcam.com!zip.eecs.umich.edu!montego!not-for-mail@network.ucsd.edu Subject: TEMPEST - Electronic Eavesdropping To: ham-ant@ucsd.edu In article <2j3m8h$m6j@percy.cs.bham.ac.uk>, Rob Jackson wrote: > >In the US it not illegal to posess TEMPEST-surveillance equipment but >it is illegal to take appropriate counter-measures to prevent >surveillance. The US government has refused to release details of its >TEMPEST research and has restricted the dissemination of independent >research by classifying it. In no way does that equate to it being illegal to attempt to suppress spurious electromagnetic radiation from computing devices. The FCC even has rules requiring EMI/RFI filtering & suppression for civillian & commercial computers & peripherals, albeit not in the name of national security. >The US Drug Enforcement Agency (DEA) makes use of >TEMPEST secured >electronics and computers as they believe that the drug cartels may >possess surveillance equipment. > Yes & no. Some DEA processing machines contain or are capable of accessing classified information. That alone requires the machines and/or their containing room to meet certain TEMPEST criteria. The classified info is what necessitates TEMPEST, and not specifically the belief that narcotic organizations are using Van Eck devices, etc. -- Tim Tyler Internet: tim@ais.org Packet: KA8VIR @WB8ZPN.#SEMI.MI.USA.NA P.O. Box 443 C$erve:72571,1005 GEnie:Sneaker AOL:Hooligan MCI: 442-5735 Ypsilanti MI "I'm just an innocent little frog, trying to 48197 hop my way across the Information Superhighway" ------------------------------ Date: Sun, 30 Jan 1994 21:37:03 GMT From: news.Hawaii.Edu!uhunix3.uhcc.Hawaii.Edu!jherman@ames.arpa To: ham-ant@ucsd.edu References <1994Jan28.201536.11492@bongo.tele.com>, <2683@indep1.chi.il.us>, Subject : Re: Dipole supplies Julian asked about dipole supplies, including what type of rope to use. I suggested to him, via email, that dacron line is the only rope he should consider, for consider this: almost every sailboat on the water today uses only dacron line and dacron sails; dacron holds up against UV radiation exceptionally well and stretches very little. It will last for many years. My sailboat is 10 years old, and several of the dacron halyards are original; they sit out in the hot Hawaiian sun year after year and are still in fine shape. You can buy it by the foot at any marine store. 73, Jeff NH6IL ------------------------------ Date: Wed, 2 Feb 1994 20:36:30 GMT From: hearst.acc.Virginia.EDU!cscsun!dtiller@uunet.uu.net To: ham-ant@ucsd.edu References <1994Jan25.191446.1@ntuvax.ntu.ac.sg>, , <1994Jan31.001134.1@ntuvax.ntu.ac.sg>.com Subject : Re: Antenna pre-amps. asirene@ntuvax.ntu.ac.sg wrote: : 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? ------------------------------ End of Ham-Ant Digest V94 #25 ****************************** ******************************