Date: Tue, 26 Jul 94 04:30:13 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 #239 To: Ham-Ant Ham-Ant Digest Tue, 26 Jul 94 Volume 94 : Issue 239 Today's Topics: Channel Master Antenna -- where to buy? Feedline next to 220V run?? Feed lines and AC power (2 msgs) How to match 2-meter 1/2 wave mfj 1796 What coax feed to use for 2m antenna 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: 25 Jul 1994 10:19:26 GMT From: ihnp4.ucsd.edu!swrinde!pipex!lyra.csx.cam.ac.uk!pmms.cam.ac.uk!andrew@network.ucsd.edu Subject: Channel Master Antenna -- where to buy? To: ham-ant@ucsd.edu I'm trying to buy a Channel Master 4408 FM Antenna from the States (on the grounds they don't make 'em that big in Europe). Is anyone able to suggest a supplier who would ship to the UK? I tried writing to the manufacturers but got no reply. Many thanks, Andrew Thomason (andrew@dpmms.cam.ac.uk) ------------------------------ Date: 25 Jul 1994 11:12:30 GMT From: flex.com!mango.flex.com!mlh@uunet.uu.net Subject: Feedline next to 220V run?? To: ham-ant@ucsd.edu Karl Beckman (CSLE87@email.mot.com) wrote: : In article , trb@cray.com (Tom Baltz) : wrote: : > I'd like to run some RG8 coax from a 2 meter jpole in my attic ..antenna : > restrictions :-( .. to my toyroom...the garage. My other hobby : > (woodworking) is requiring a 220V line coming from the attic to the same : > 'toyroom' for my tablesaw. Its a 2 story house, so I need to feed both : > lines through a bedroom closet that is located above the garage. Can I : > run both feeds thru the same conduit?? : > ... : NO, NO, NO!! The National Electric Code requires that they be in separate : conduits and junction boxes. Section 810 deals with Radio, TV, and amateur : radio stations. Power and communications signal circuits may NEVER be : combined in the same conduit. They must be physically separated by at : least 2 inches unless the power wiring is in non-combustible (metal) : conduit or metallic armored cable. You _can_ lace the coax cable to the : metallic conduit, so that the conduit provides mechanical support for the : vertical run. The ARRL Handbook has always said to keep power lines as far away from antennas and lead-in cables as possible... not only for safety, but to prevent cross-talk. The shield braid of coax will not do anything to prevent magnetic coupling from occurring. The conductive shielding around coax is only good for electrostatic signals. John KJ9U/KH6 mlh@flex.com ------------------------------ Date: Mon, 25 Jul 1994 15:10:48 GMT From: ihnp4.ucsd.edu!swrinde!gatech!news-feed-1.peachnet.edu!emory!rsiatl!ke4zv!gary@network.ucsd.edu Subject: Feed lines and AC power To: ham-ant@ucsd.edu In article <30tsi0$46s@hopper.acm.org> smithson@ACM.ORG writes: >Greetings! > >I'm getting ready to dig a deep trench from my house to my barn (120') to >get water and power out there. The barn is in the middle of a large pasture, >and is also very close to where I plan to put a tower some day. My question >is this. Would there be any problem in running some coax out to the barn >in the same trench? The water and power will be enclosed in 4" PVC pipe >and come in through the basement wall. I was thinking of putting in >another pipe and running coax, etc. through it. Any thoughts? This is a popular idea, and it works well. There are only a couple of concerns. One is common mode induction from the power wiring to the coax. You may need to place a un-un in the coax to eliminate the common mode 60 Hertz. In the video trade, we call un-uns hum-bucker coils. Another concern is ground currents. You should follow the NEC recomendation on separately grounding agricultural buildings (the only place in the NEC where divorced grounding is permitted). Otherwise you may have some unhappy livestock. 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: Mon, 25 Jul 1994 13:47:37 -0400 From: ftpbox!mothost!lmpsbbs!NewsWatcher!user@uunet.uu.net Subject: Feed lines and AC power To: ham-ant@ucsd.edu In article <30tsi0$46s@hopper.acm.org>, smithson@ACM.ORG wrote: > Greetings! > > I'm getting ready to dig a deep trench from my house to my barn (120') to > get water and power out there. The barn is in the middle of a large pasture, > and is also very close to where I plan to put a tower some day. My question > is this. Would there be any problem in running some coax out to the barn > in the same trench? The water and power will be enclosed in 4" PVC pipe > and come in through the basement wall. I was thinking of putting in > another pipe and running coax, etc. through it. Any thoughts? > > Thanks! > > -Brian n8wrl > smithson@acm.org A good and safe way to do it; just be sure the "radio/coax" pipe is big enough. By the way, while you are pulling, don't forget about telephone, rotor, intercom, and cable tv. Be sure to pull all the lines at once; it is almost impossible to pull more through at a later date without tangling and weaving them between the existing cables! -- Karl Beckman, P.E. < If this English language is so > Motorola LMPS.RNSG.Analog Data < precise, why do you drive on a > (Square waves & round corners) < parkway and park on a driveway? > Any opinions expressed here do not belong to or represent Motorola Inc. Amateur radio WA8NVW NavyMARS NNN0VBH @ NOGBN.NOASI ------------------------------ Date: 25 Jul 94 20:44:15 GMT From: ihnp4.ucsd.edu!swrinde!howland.reston.ans.net!math.ohio-state.edu!scipio.cyberstore.ca!vanbc.wimsey.com!unixg.ubc.ca!quartz.ucs.ualberta.ca!alberta!atha!aupair.cs.athabascau.ca!rwa@network. Subject: How to match 2-meter 1/2 wave To: ham-ant@ucsd.edu bmork@opus-ovh.spk.wa.us (Brian) writes: >jdc3538@ultb.isc.rit.edu (J.D. Cronin) writes: >> How does one match a 1/2 wave antenna to 50 ohms? >Cut it in half and feed it half way up, like a dipole. Or, if mechanical considerations eliminate that option, try using a tuned autotransformer - a parallel resonant LC circuit with one side to ground, one side to the end of the 1/2 lambda, and the feedline a turn or so up from the ground end of the coil. regards, Ross ve6pdq -- Ross Alexander VE6PDQ rwa@cs.athabascau.ca, (403) 675 6311 rwa@auwow.cs.athabascau.ca Television is chewing gum for the eyes. -- Frank Lloyd Wright ------------------------------ Date: 25 Jul 1994 12:01:04 GMT From: ihnp4.ucsd.edu!swrinde!gatech!newsxfer.itd.umich.edu!jobone!ukma!newsfeed.gsfc.nasa.gov!trmmstocker.gsfc.nasa.gov!stocker@network.ucsd.edu Subject: mfj 1796 To: ham-ant@ucsd.edu > From: jeff@njo.dec.com (jeff) > Subject: Re: mfj 1796 > Message-ID: <1994Jul24.120253.10757@njo.dec.com> > Summary: Have not even shipped ONE yet! > Organization: Digital Equipment, New Jersey > References: <30s5c3$rfr@apple.com> > Date: Sun, 24 Jul 1994 12:02:53 GMT > Lines: 12 > > In article <30s5c3$rfr@apple.com> kchen@apple.com (Kok Chen) writes: > > > >Would be kinda difficult to load this antenna, I imagine. Being an > >imaginary antenna, it obviously has an impedance of z = i50 ohms. > > > > I heard from a very reliable source yesterday (has had the mfj1796 on order > for 22months now!), that they have not even shipped ONE of these and that > they are still awaiting hardware to complete this critters... the above > comment is too accurate! > > n2mzh -jj I think that your reliable sources aren't too reliable. I saw this antenna at two Timonimum hamfests. It was carried by Delaware Amateur Supply, I think. I thought of buying it but they were selling at full retail. Don't know how many they had and I know that supply is erratic but they had it right on the floor and you could take the box with you. Perhaps, you mean the new 1798 that includes the 80m band? 73, Erich ******************************************* * Erich Franz Stocker * * N3OXM * * stocker@spsosun.gsfc.nasa.gov * * * * My ideas are my own and do not represent* * the opinions of the federal government, * * NASA or Goddard Space Flight Center. * ******************************************* ------------------------------ Date: 25 Jul 1994 15:39:44 GMT From: newsgate.watson.ibm.com!watnews.watson.ibm.com!vinod@uunet.uu.net Subject: What coax feed to use for 2m antenna To: ham-ant@ucsd.edu I am going to put up some sort of 2m antenna on (or just under) my roof. I will probably start with a "twin-lead" J-pole suspended from outside the roofline, and then switch to a SO-239 quarter wave or a copper-tube J-pole, maybe even a Yagi later. For now, I will be using my HT. I want to put up the righ coax-line for the feed just once, and connect the antenna using connectors. So, 1. What type of coax should I put up? 2. What type of connectors should I use at the antenna end for coupling the long feedline with the (short) connecting coax from the antenna? Many thanks in advance. --vinod, N2ZKE email: vinod@watson.ibm.com ------------------------------ End of Ham-Ant Digest V94 #239 ******************************