Date: Sun, 2 Jan 94 04:30:15 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 V93 #160 To: Ham-Ant Ham-Ant Digest Sun, 2 Jan 94 Volume 93 : Issue 160 Today's Topics: Commercial Antenna Tuners Radials for Ground-Mounted Verticals Wanted- Antenna Mast 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, 2 Jan 94 03:41:35 EST From: usc!howland.reston.ans.net!noc.near.net!news.delphi.com!usenet@network.ucsd.edu Subject: Commercial Antenna Tuners To: ham-ant@ucsd.edu Charles -- I've heard the "Mighty Fine Junk" references, and they are accuarate in relation to some MFJ products, such as their 2 meter 5/8 wave antenna, but not with respect to the tuners -- at least in my experience. I'm on my second MFJ tuner, this one being the MFJ-986 that you referred to. With it, I have no problem loading a twin-lead fed 80 meter inverted V on everything from 160 to 10 meters. Depending on the length of your feed line, it can take some tweaking (on parts of 20 meters, I can't get below about a 1.5:1 SWR no matter what), but it has been very reliable and lot of Europeans can't believe I'm running barefoot. 73 de Lee/KE3FB in Md. leevankoten@delphi.com ------------------------------ Date: 1 Jan 1994 22:05:29 GMT From: usc!math.ohio-state.edu!magnus.acs.ohio-state.edu!wvanhorn@network.ucsd.edu Subject: Radials for Ground-Mounted Verticals To: ham-ant@ucsd.edu >gary@ke4zv.atl.ga.us (Gary Coffman) wrote: >220 66 foot radials laid out on the snow will work wonderfully well. >That's a broadcast quality ground screen. You should be able to get >by with 16 however for amateur quality. Actual contact with the ground >isn't necessary, and the length needs to be a quarterwave at the lowest >frequency you're going to operate. Just arrange them like the spokes of >a wheel with the antenna in the center. Gary - What you advise is time-honored and certainly does work "wonderfully well." But in QST, March, 1993, "Technical Correspondence", p. 72, Al Christman, KB8I, presents information that, if verified, will surely overturn 75 years of "conventional wisdom". In a letter titled: "More on Elevated Radials", he gives the results of computer studies using NEC software indicating that as few as 4 radials, elevated 10 feet above the ground, are as effective as 120 lying on, or under, the ground! His letter summarized work that he and a collaborator, Radcliffe, reported in a formal paper printed in IEEE TRANSACTIONS ON BROADCASTING, September, 1991, pp. 77-82. In that paper, they modeled a broadcast- frequency tower ground-mounted; the coax feed-point was at ground level, and the radials rose at 45-degree angle to the 10-feet height, extending at that height for one-quarter wavelength. In his QST letter, KB8I reported extending the work to the 80-meter ham band. He found that, at that frequency, results were nearly as good with the radials raised no higher than 4 or 5 feet above ground. In your recent posting did you consider this alternative, or don't you believe it? 73, Van - W8UOF * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * It ain't wot you don't know 't gets you into trouble. * * It's wot you know 't ain't true. - "Mr. Dooley" * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * wvanhorn@magnus.acs.ohio-state.edu ------------------------------ Date: 01 Jan 94 15:51:00 -0500 (EST) From: blkcat!1-109-239-0!Gary.Mitchelson@uunet.uu.net Subject: Wanted- Antenna Mast To: ham-ant@ucsd.edu I am looking for a source of telescoping antenna masts in the 25 to 35 foot range. I have seen them at hamfests and I can kick myself for not having bought one then. I have seen a couple of different types, they all seem to be surplus, have either a mechanical or hydralic means of raising and sell for $100-$150 in good condition. The bottom sections are around 5" in diameter and the tops are 2" in diameter. I need one to support a 144 & 432 Mhz quad and a 6M X-Beam. If anyone knows where I can find one please let me know. N3JPU *** * SLMR 2.1a * Death - nature's way of saying "Slow down" ------------------------------ End of Ham-Ant Digest V93 #160 ****************************** ******************************