+++++++++++++++++ Date: Wed, 1 May 2002 20:25:23 -0400 From: "Paul Christensen" To: , "Low Power Amateur Radio Discussion" Subject: [125883] Re: St. Louis Verticals > running 200mW. Nobody was digging anyone out of the mud. We have done > several A-B antenna comparisons, with me switching between the St. Louis > vertical and my G5RV up 35 feet, a Butterworth vertical, etc. Sure, the > later antennas bring in a bit better signal, but a single S-unit difference > at best. Like any other ground-mounted, base-fed vertical, the SLV's radiated efficiency is a function of the ground system beneath it. When camping, the SLV is still my antenna of choice. I have no trouble deploying 24 radials of 24 AWG wire in less than ten minutes. With an adequate radial system, the SLV on 40-meters is easily capable of performance equal to a dipole at a quarter-wave in height...of course the SLV will have a much lower angle of radiation than the dipole and is not as good for distances up to 400 miles or so. -Paul, W9AC +++++++++++++++++ Date: Wed, 1 May 2002 20:51:55 -0400 From: "Mike Yetsko" To: , "Low Power Amateur Radio Discussion" Subject: [125885] Re: St. Louis Verticals Oh, they're neat! Basically, a vertical pole with a wire up. 20 feet if you can. With a coil at the base. Cheap. Easy to build. Easy to set up and take down. And works fairly well... Mike ----- Original Message ----- From: "Dave" To: "Low Power Amateur Radio Discussion" Sent: Wednesday, May 01, 2002 8:29 PM Subject: Re: St. Louis Verticals > Ok guys, > Now I have to search the web to see what a St. Louis Vertical is! > Dave > WR3I +++++++++++++++++ Date: Thu, 2 May 2002 12:01:55 -0400 From: "Hare,Ed, W1RFI" To: Low Power Amateur Radio Discussion Subject: [125902] RE: St. Louis Verticals > Like any other ground-mounted, base-fed vertical, the SLV's radiated > efficiency is a function of the ground system beneath it. That is true. The low-angle performance of a vertical antenna is also dependent on the characteristics of the ground many wavelengths away from the antenna. Over poor ground, a radial system will minimize the ohmic losses of the ground connection, but the poor ground outside the radial system can still absorb the low radiation angles. 73, Ed Hare, W1RFI ARRL Lab 225 Main St Newington, CT 06111 Tel: 860-594-0318 Internet: w1rfi at arrl.org Web: http://www.arrl.org/tis +++++++++++++++++ Date: Thu, 02 May 2002 00:07:56 GMT From: na5n at zianet.com To: david.gauding at bbs.galilei.com Cc: "Low Power Amateur Radio Discussion" Subject: [125879] Re: St. Louis Verticals My comment to this is ... I have built several St. Louis Verticals over the years, with and without the W6MMA loading coil ... which incidentally is what TUNES the darn antenna since it is NOT a self-tuned antenna as the original article fully describes. I have used them on numerous "to the field" contests over the past several years, from our famous Area 51 and Mexican border QRPTTF's to a couple of FYBO's. I have also had many late-night 40M QSO's with Dave, NF0R himself with us both using St. Louis verticals, often times with Dave running 200mW. Nobody was digging anyone out of the mud. We have done several A-B antenna comparisons, with me switching between the St. Louis vertical and my G5RV up 35 feet, a Butterworth vertical, etc. Sure, the later antennas bring in a bit better signal, but a single S-unit difference at best. The point is, the St. Louis vertical was never published to compete with a Force 12 or $350 commercial vertical antenna. But if you want a vertical that costs you a few bucks that folds up into a tube to take virtually anywhere to get on the air easily, by golly it does that. I think Dave and the SLQS gang have made some very nice contributions to the QRP hobby, and have always been honest about it's capabilities and shortcomings. The St. Louis tuner and one of the St. Louis vertical antennas have allowed a lot of people to get on "in the field" very easily. I do think the article was a bit misleading in evaluating it, but that is the only comment I will make on that. But like Dave's main concern, I don't want anyone to think it is a poor choice to make if you want a simple, "to the field" type antenna. I have no idea how it "looks" if you model it with one of the current antenna programs, but I know empirically, they work. I don't blame Dave at all for defending the excellent contributions of many of the SLQS members over the years. 72, Paul NA5N +++++++++++++++++ Date: Fri, 3 May 2002 15:11:57 EDT From: ARDUJENSKI at aol.com To: qrp-l at lehigh.edu Subject: [125937] St. Louis Vertical--Food for thought Running the programs made available by REG G4FGQ here are some efficiency results for 40m on a 20ft Black Widow pole: St. Louis (original)----- 28 percent St. Louis (W6MMA coil )--37 percent Inverted-L (20ft by 20ft)---- 46 percent These are using approximations with soil and coil info. What you can see you can get an increase in efficiency with the Inverted-L but not quite double over the origianal St. Louis Vertical which is less than 1/2 S-unit. I will let you put this in perspective regarding costs and designs and ease of use. I think side by side you would be hard pressed to tell the difference performance wise. Me --well I have a soft spot for that coiled helix at the base of the pole (smile) Alan KB7MBI in Woodinville, WA FISTS 5702 Proud member of ARRL +++++++++++++++++ Date: Fri, 03 May 2002 15:22:38 -0500 From: David Gauding To: qrp-l at lehigh.edu Cc: radioham at gmx.co.uk Subject: [125941] Re: St. Louis Vertical--Food for thought Hello Ray, W6MMA ceased production of his coil mod for the SLV almost two years ago. You can pretty much duplicate Vern Wright's mod with a homebrew tapped wire coil designed by AA0CW (ex-N0TFI). A keyword search should bring-up the URL for his website though the last time I was on it was well over a year ago. The tapped wire coil uses a section of closed-cell foam pipe insulation as a coil form. It slips over the top of the pole and friction keeps it in place. Very light too. The foam insulation is already slit along it's length which eliminates doing any surgery on the form. The tap is a simple extension at the base of the coil, terminated in an alligator clip. It's a wonderful project, real ham radio, and will work about the same as a commercial design. If you can find a SLV/W6MMA kit that would be great. If not, the AA0CW hombrew coil will also do a fine job. Good luck, de Dave, NF0R nf0r at slacc.com At 08:47 PM 5/3/02 +0100, you wrote: >Hi, > >All interesing stuff, I have been looking for a URL for the modified SLV >with the W6MMA coil since this thread started, but I cannot find anything. >Does anybody have a suggestion where to look? > >72/73's > >Ray G4FON > > > Running the programs made available by REG G4FGQ here are some efficiency > > results for 40m on a 20ft Black Widow pole: > > > > St. Louis (original)----- 28 percent > > > > St. Louis (W6MMA coil )--37 percent +++++++++++++++++++ Date: Fri, 3 May 2002 16:52:54 -0400 (EDT) From: Stephan Greene To: Low Power Amateur Radio Discussion Subject: [125942] Re: St. Louis Vertical--Food for thought Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII On Fri, 3 May 2002, David Gauding wrote: > You can pretty much duplicate Vern Wright's mod with a homebrew tapped wire > coil designed by AA0CW (ex-N0TFI). A keyword search should bring-up the URL > for his website though the last time I was on it was well over a year ago. I did a google search and it appears that the website referred to is no longer active (http://www.concentric.net/~jessqrp) I *did* find two articles in the QRP-L archives that apepar relevant: http://qrp.kd4ab.org/2000/000809/0048.html General posting (8/9/00) by NF0R about the SLV, it's limitations, and enhacenements. http://qrp.kd4ab.org/1997/970411/0001.html Posting (4/11/97) from N0TFI describing the coil mod. > The tapped wire coil uses a section of closed-cell foam pipe insulation as > a coil form. It slips over the top of the pole and friction keeps it in > place. Very light too. The foam insulation is already slit along it's > length which eliminates doing any surgery on the form. Hope this helps 73 Steve KA1LM +++++++++++++++++++