From oz1axg.nospam at dxmail.dk Fri Nov 6 06:08:08 2009 From: oz1axg.nospam at dxmail.dk (OZ1AXG Flam) Date: Fri, 6 Nov 2009 15:08:08 +0100 Subject: [Antennaware] K9AY RxLoop with 2 turn loop (160m) References: <41486A9D70CA4A0CBB0496FFAEFA762D@BobsLaptop> Message-ID: <007f01ca5eed$45886ff0$0601a8c0@X502> Hi Experts! I read on the internet that adding "turns" to the Loop could improve signal strength ? Question: how much would signal improve adding one extra turn (n=2) versus single loop (n=1) ? The loop im currently deployed has loop size = 28 meters and is pretty much standard dimentions... Adding another 28 meter could me be a mechanical challenge since the two wire would bounce around when windy ... how would this impact performance ? -- Kind Regards OZ1AXG Flam Current setup: http://home.cbkn.dk/dx/dualk9ay.htm From andrew.ikin at btopenworld.com Fri Nov 6 15:11:31 2009 From: andrew.ikin at btopenworld.com (Andy Ikin) Date: Fri, 6 Nov 2009 23:11:31 -0000 Subject: [Antennaware] K9AY RxLoop with 2 turn loop (160m) References: <41486A9D70CA4A0CBB0496FFAEFA762D@BobsLaptop> <007f01ca5eed$45886ff0$0601a8c0@X502> Message-ID: <917FABDE2FC44243A7CF00AD09132278@wellbroocg9mnv> Dear Flam, You wrote on the 6th Nov 2009. I read on the internet that adding "turns" to the Loop could improve signal strength ? The following was posted by me on the K9AY Groups (digest no 78) back in late 2000. "Hi K9AYers, Tracey finally "brow beat" me to experimenting with some loop configurations suggested by Johan Bodin a few months ago. Without going into lengthy detail, one configuration consisted of two loops mounted at right angles connected in series. To my surprise I measured a 5/6dB increase in gain over the normal K9AY config. As a co-incidence, an e-mail from Gary was forward to me, giving details of a 6dB increase gain using a two turn loop with a resistive plus reactive termination. Therefore, I had to see if a single loop of two turns would work for LW and MW with just resistive termination. Well as far as I can see, the answer is yes, but only if the turns are separated to reduce mutual coupling i.e. using a twin lead wire loop connect in series only provides about a 2 dB gain increase. Separating the delta loops by 1m at each end of the loop i.e. two poles at each end. The loops cross at the apex. This provided the 5/6dB gain increase. I would be interested in hearing from other users if my findings can be replicated. The only reason I can explain for this increase in gain is that the 450-50 match xmfr is not optimised for LW/MW. Hence raising the antenna impedance with two turn loop provides a better Match! So the experimentation continues!!!" I don't have any more information on this 2 turn configuration. 73 Andy From b38 at hilding.com Sun Nov 8 23:07:12 2009 From: b38 at hilding.com (Eric Hilding) Date: Sun, 8 Nov 2009 23:07:12 -0800 Subject: [Antennaware] YO Problem Message-ID: <015101ca610b$430a8d60$c91fa820$@com> I'm back to picking up where I left off trying to model multi element wire yagis for 80m & 40m in YO, but can't seem to figure out several problems. The most salient being, that the driven element remains longer than the Reflector (no, the DE length is not locked), regardless of how many hours the Confuzer keeps doing iterations. No response from K6STI ;-( Any assistance would be appreciated. Tnx & 73. Rick, K6VVA * The Locust From olinger at bellsouth.net Mon Nov 9 16:54:51 2009 From: olinger at bellsouth.net (Guy Olinger K2AV) Date: Mon, 9 Nov 2009 19:54:51 -0500 Subject: [Antennaware] YO Problem In-Reply-To: <015101ca610b$430a8d60$c91fa820$@com> References: <015101ca610b$430a8d60$c91fa820$@com> Message-ID: <46f338980911091654i3fa85656n7a18dbba2a04359d@mail.gmail.com> Perhaps one of the reasons is that the best gain and pattern is not necessarily at a 50 ohm zero reactance point on the DE, in some cases "miles" away from 50 J0. I found this consistently with a lot of AO Pro runs on wire yagi's and quads. Since none of the people I was designing for wanted to deal with a non-50-ohm-resistive feedpoint, I locked in that restriction in the AO parms and let the other lengths (and inferior gain) fall where they may. I don't know why people think 50 ohms is some kind of natural law, or why SWR is king of all radio considerations, but that's sure the way they think. Problem occurs when nature and physics don't play along with our obsessions. As to trying to get in touch with K6STI, I don't think he is talking to hams any more. His attitude was really soured by software piracy. 73, Guy. On Mon, Nov 9, 2009 at 2:07 AM, Eric Hilding wrote: > I'm back to picking up where I left off trying to model multi element wire > yagis for 80m & 40m in YO, but can't seem to figure out several problems. > The most salient being, that the driven element remains longer than the > Reflector (no, the DE length is not locked), regardless of how many hours > the Confuzer keeps doing iterations. No response from K6STI ;-( > > > > Any assistance would be appreciated. > > > > Tnx & 73. > > > > Rick, K6VVA * The Locust > > > > _______________________________________________ > Antennaware mailing list > Antennaware at contesting.com > http://lists.contesting.com/mailman/listinfo/antennaware > From dave at g3ueg.co.uk Thu Nov 12 09:33:40 2009 From: dave at g3ueg.co.uk (David Gould) Date: Thu, 12 Nov 2009 17:33:40 +0000 Subject: [Antennaware] plot comparisons Message-ID: <20091112173343.SBUS21638.aamtaout02-winn.ispmail.ntl.com@g3ueg.g3ueg.co.uk> This question is a long shot, but knowing the resourcefulness of the group I thought I would ask anyway.. I am doing some comparisons of various receive antennas, some of which have very different gains. I am overlaying different plot files to compare the patterns, especially the pattern off the back. This has been quite difficult on occasions because of the big gain differences. I wondered if there was a way to "normalise" the gain of two plots so as to be able to get an easier comparison? Another way of saying it would be to able to make the gain of the outer rings of two plots identical? Is it possible or are there any other techniques to simplify the comparisons? Thanks for any ideas. 73, Dave, G3UEG From dave at g3ueg.co.uk Thu Nov 12 11:02:35 2009 From: dave at g3ueg.co.uk (David Gould) Date: Thu, 12 Nov 2009 19:02:35 +0000 Subject: [Antennaware] plot comparisons - addition Message-ID: <20091112190239.VLT2093.aamtaout03-winn.ispmail.ntl.com@g3ueg.g3ueg.co.uk> I should have added that I am using EZNEC+ V5 73, Dave This question is a long shot, but knowing the resourcefulness of the group I thought I would ask anyway.. I am doing some comparisons of various receive antennas, some of which have very different gains. I am overlaying different plot files to compare the patterns, especially the pattern off the back. This has been quite difficult on occasions because of the big gain differences. I wondered if there was a way to "normalise" the gain of two plots so as to be able to get an easier comparison? Another way of saying it would be to able to make the gain of the outer rings of two plots identical? Is it possible or are there any other techniques to simplify the comparisons? Thanks for any ideas. 73, Dave, G3UEG From k9ay at k9ay.com Thu Nov 12 11:55:52 2009 From: k9ay at k9ay.com (K9AY) Date: Thu, 12 Nov 2009 13:55:52 -0600 Subject: [Antennaware] plot comparisons - addition References: <20091112190239.VLT2093.aamtaout03-winn.ispmail.ntl.com@g3ueg.g3ueg.co.uk> Message-ID: <6026AD6107974D81BED90A94C737D9BB@SUMMIT1> Dave, EZNEC does this automatically if you recall a saved trace and add it to the current trace. If you are overlaying exported bitmap files in a graphics program, choose a fixed outer ring value in the 'Desc Options' setup. Gary K9AY >I should have added that I am using EZNEC+ V5 > > 73, > Dave > > > > > This question is a long shot, but knowing the resourcefulness of the > group I thought I would ask anyway.. > > I am doing some comparisons of various receive antennas, some of > which have very different gains. I am overlaying different plot > files to compare the patterns, especially the pattern off the back. > This has been quite difficult on occasions because of the big gain > differences. > > I wondered if there was a way to "normalise" the gain of two plots > so as to be able to get an easier comparison? Another way of saying > it would be to able to make the gain of the outer rings of two plots > identical? > > Is it possible or are there any other techniques to simplify the > comparisons? > > Thanks for any ideas. > > 73, > Dave, G3UEG > > _______________________________________________ > Antennaware mailing list > Antennaware at contesting.com > http://lists.contesting.com/mailman/listinfo/antennaware From n6ry at arrl.net Thu Nov 12 16:36:25 2009 From: n6ry at arrl.net (Terry Conboy) Date: Thu, 12 Nov 2009 16:36:25 -0800 Subject: [Antennaware] plot comparisons - addition In-Reply-To: <6026AD6107974D81BED90A94C737D9BB@SUMMIT1> References: <20091112190239.VLT2093.aamtaout03-winn.ispmail.ntl.com@g3ueg.g3ueg.co.uk> <6026AD6107974D81BED90A94C737D9BB@SUMMIT1> Message-ID: <4AFCAA09.8010704@arrl.net> When I overlay the elevation plot for a 4 square array on top of the plot of single vertical, the plot for the single vertical is ~5 dB down from the 4 sq. I tried setting the reference gain for the outer ring of the plot to a fixed higher value (in Desc Options) before saving the plot to shrink it, but the program still displays the higher gain antenna plot larger than the lower gain antenna by the ratio of the gains when overlaid. I see Dave's dilemma. Perhaps Gary has an option set that I have missed to allow the maxima of the plots to be coincident, even though the absolute gains differ. 73, Terry N6RY On 2009-11-12 11:55 AM, K9AY wrote: > Dave, > > EZNEC does this automatically if you recall a saved trace and add it to the > current trace. If you are overlaying exported bitmap files in a graphics > program, choose a fixed outer ring value in the 'Desc Options' setup. > > Gary > K9AY > > >> This question is a long shot, but knowing the resourcefulness of the >> group I thought I would ask anyway.. >> >> I am doing some comparisons of various receive antennas, some of >> which have very different gains. I am overlaying different plot >> files to compare the patterns, especially the pattern off the back. >> This has been quite difficult on occasions because of the big gain >> differences. >> >> I wondered if there was a way to "normalise" the gain of two plots >> so as to be able to get an easier comparison? Another way of saying >> it would be to able to make the gain of the outer rings of two plots >> identical? >> >> Is it possible or are there any other techniques to simplify the >> comparisons? >> >> Thanks for any ideas. >> >> 73, >> Dave, G3UEG >> >> I should have added that I am using EZNEC+ V5 From dave at g3ueg.co.uk Fri Nov 13 01:33:16 2009 From: dave at g3ueg.co.uk (David Gould) Date: Fri, 13 Nov 2009 09:33:16 +0000 Subject: [Antennaware] plot comparisons In-Reply-To: <4AFCAA09.8010704@arrl.net> References: <20091112190239.VLT2093.aamtaout03-winn.ispmail.ntl.com@g3ueg.g3ueg.co.uk> <6026AD6107974D81BED90A94C737D9BB@SUMMIT1> <4AFCAA09.8010704@arrl.net> Message-ID: <20091113093336.ZYXY21638.aamtaout02-winn.ispmail.ntl.com@g3ueg.g3ueg.co.uk> Thanks to all who have replied. I must apologise for the mess I made of asking the question, looking back I did not make myself at all clear, and congratulation to Terry for seeing through the confusion and picking up correctly on what I was trying to ask. His last paragraph, below, sums up perfectly what I am trying to achieve. It is an electronic version of printing off the two individual plots onto clear actetate and then overlaying them physically, in which case the gains of the outer rings will be different. 73, Dave, G3UEG At 00:36 13/11/2009, Terry Conboy wrote: >When I overlay the elevation plot for a 4 square array on top of the >plot of single vertical, the plot for the single vertical is ~5 dB down >from the 4 sq. I tried setting the reference gain for the outer ring of >the plot to a fixed higher value (in Desc Options) before saving the >plot to shrink it, but the program still displays the higher gain >antenna plot larger than the lower gain antenna by the ratio of the >gains when overlaid. I see Dave's dilemma. > >Perhaps Gary has an option set that I have missed to allow the maxima of >the plots to be coincident, even though the absolute gains differ. > >73, Terry N6RY From k9ay at k9ay.com Fri Nov 13 07:27:04 2009 From: k9ay at k9ay.com (K9AY) Date: Fri, 13 Nov 2009 09:27:04 -0600 Subject: [Antennaware] plot comparisons References: <20091112190239.VLT2093.aamtaout03-winn.ispmail.ntl.com@g3ueg.g3ueg.co.uk><6026AD6107974D81BED90A94C737D9BB@SUMMIT1><4AFCAA09.8010704@arrl.net> <20091113093336.ZYXY21638.aamtaout02-winn.ispmail.ntl.com@g3ueg.g3ueg.co.uk> Message-ID: <3E2F1786233E4C69974C0E2826ED1A3E@SUMMIT1> Dave and all, To quote from W7EL's Help File: "Note that .pf format files saved as 'trace files' are not graphics files. They are binary files which contain only numerical field strength data, and no information about how to plot or display it." Thus, gain is part of the saved data in EZNEC and overlaid plots within EZNEC will always be displayed with that gain difference. To do what you want, you'll need to do the multi-plot overlay outside of EZNEC, in a graphics program. With the default 'Automatic' setting in Desc Options, all exported plots will have max. gain at the outer ring. If you want to maintain the gain difference, it's necessary to set the outer ring to a fixed value for all plots to be exported. Gary K9AY > Thanks to all who have replied. > > I must apologise for the mess I made of asking the question, looking > back I did not make myself at all clear, and congratulation to Terry > for seeing through the confusion and picking up correctly on what I > was trying to ask. > > His last paragraph, below, sums up perfectly what I am trying to > achieve. It is an electronic version of printing off the two > individual plots onto clear actetate and then overlaying them > physically, in which case the gains of the outer rings will be different. > > 73, > Dave, G3UEG > > > At 00:36 13/11/2009, Terry Conboy wrote: >>When I overlay the elevation plot for a 4 square array on top of the >>plot of single vertical, the plot for the single vertical is ~5 dB down >>from the 4 sq. I tried setting the reference gain for the outer ring of >>the plot to a fixed higher value (in Desc Options) before saving the >>plot to shrink it, but the program still displays the higher gain >>antenna plot larger than the lower gain antenna by the ratio of the >>gains when overlaid. I see Dave's dilemma. >> >>Perhaps Gary has an option set that I have missed to allow the maxima of >>the plots to be coincident, even though the absolute gains differ. >> >>73, Terry N6RY From n6ry at arrl.net Fri Nov 13 10:41:17 2009 From: n6ry at arrl.net (Terry Conboy) Date: Fri, 13 Nov 2009 10:41:17 -0800 Subject: [Antennaware] plot comparisons In-Reply-To: <3E2F1786233E4C69974C0E2826ED1A3E@SUMMIT1> References: <20091112190239.VLT2093.aamtaout03-winn.ispmail.ntl.com@g3ueg.g3ueg.co.uk><6026AD6107974D81BED90A94C737D9BB@SUMMIT1><4AFCAA09.8010704@arrl.net> <20091113093336.ZYXY21638.aamtaout02-winn.ispmail.ntl.com@g3ueg.g3ueg.co.uk> <3E2F1786233E4C69974C0E2826ED1A3E@SUMMIT1> Message-ID: <4AFDA84D.6060006@arrl.net> I tried Gary's approach of using an external graphic program with the simple "Paint" program that is included in Win XP. From the 2D plot window in EZNEC, I used Edit - Copy Plot, then pasted the plot image into Paint. Then I opened the second antenna file, ran FF Plot and repeated Edit - Copy Plot and pasted the second image directly on top of the first plot in Paint. If you uncheck the Image - Draw Opaque option, you will see the two plots overlaid on each other with the same max relative gain. If you want, you can then do File - Save As in your choice of graphic format. (A .gif works pretty well for line plots like this.) 73, Terry N6RY On 2009-11-13 7:27 AM, K9AY wrote: > Dave and all, > > To quote from W7EL's Help File: > > "Note that .pf format files saved as 'trace files' are not graphics files. > They are binary files which contain only numerical field strength data, and > no information about how to plot or display it." > > Thus, gain is part of the saved data in EZNEC and overlaid plots within > EZNEC will always be displayed with that gain difference. > > To do what you want, you'll need to do the multi-plot overlay outside of > EZNEC, in a graphics program. With the default 'Automatic' setting in Desc > Options, all exported plots will have max. gain at the outer ring. If you > want to maintain the gain difference, it's necessary to set the outer ring > to a fixed value for all plots to be exported. > > Gary > K9AY > > > > >> Thanks to all who have replied. >> >> I must apologise for the mess I made of asking the question, looking >> back I did not make myself at all clear, and congratulation to Terry >> for seeing through the confusion and picking up correctly on what I >> was trying to ask. >> >> His last paragraph, below, sums up perfectly what I am trying to >> achieve. It is an electronic version of printing off the two >> individual plots onto clear actetate and then overlaying them >> physically, in which case the gains of the outer rings will be different. >> >> 73, >> Dave, G3UEG >> >> >> At 00:36 13/11/2009, Terry Conboy wrote: >> >>> When I overlay the elevation plot for a 4 square array on top of the >>> plot of single vertical, the plot for the single vertical is ~5 dB down >>> >> >from the 4 sq. I tried setting the reference gain for the outer ring of >> >>> the plot to a fixed higher value (in Desc Options) before saving the >>> plot to shrink it, but the program still displays the higher gain >>> antenna plot larger than the lower gain antenna by the ratio of the >>> gains when overlaid. I see Dave's dilemma. >>> >>> Perhaps Gary has an option set that I have missed to allow the maxima of >>> the plots to be coincident, even though the absolute gains differ. >>> >>> 73, Terry N6RY >>> > > _______________________________________________ > Antennaware mailing list > Antennaware at contesting.com > http://lists.contesting.com/mailman/listinfo/antennaware > > From k9ay at k9ay.com Fri Nov 13 12:03:19 2009 From: k9ay at k9ay.com (K9AY) Date: Fri, 13 Nov 2009 14:03:19 -0600 Subject: [Antennaware] plot comparisons References: <20091112190239.VLT2093.aamtaout03-winn.ispmail.ntl.com@g3ueg.g3ueg.co.uk><6026AD6107974D81BED90A94C737D9BB@SUMMIT1><4AFCAA09.8010704@arrl.net> <20091113093336.ZYXY21638.aamtaout02-winn.ispmail.ntl.com@g3ueg.g3ueg.co.uk> <3E2F1786233E4C69974C0E2826ED1A3E@SUMMIT1> <4AFDA974.7050104@arrl.net> Message-ID: Most graphics programs let you rotate, flip and change colors. One handy action is to show all patterns of directional arrays -- e.g. to show the four directions of a 4-square, I simply take the original plot, copy, rotate and pick another color. The final result is an at-a-glance view of all directions, with 3 dB points, overlap, null locations, etc. easy to identify. Whenever there is symmetry, It's usually easier to do this graphically than to re-do the EZNEC file. Garry K9AY ----- Original Message ----- From: Terry Conboy To: K9AY Cc: David Gould Sent: Friday, November 13, 2009 12:46 PM Subject: Re: plot comparisons I tried Gary's approach of using an external graphic program with the simple "Paint" program that is included in Win XP. From the 2D plot window in EZNEC, I used Edit - Copy Plot, then pasted the plot image into Paint. Then I opened the second antenna file, ran FF Plot and repeated Edit - Copy Plot and pasted the second image directly on top of the first plot in Paint. If you uncheck the Image - Draw Opaque option in Paint, you will see the two plots overlaid on each other with the same max relative gain. If you want, you can then do File - Save As in your choice of graphic format. (A .gif works pretty well for line plots like this.) 73, Terry N6RY From hsgorden at comcast.net Mon Nov 16 14:32:37 2009 From: hsgorden at comcast.net (Howard W3CQH) Date: Mon, 16 Nov 2009 17:32:37 -0500 Subject: [Antennaware] FRACTAL Message-ID: With my chemo brain, I don't remember if I asked this question of the groups before. I am looking to buy a back issue of 73' magazine that contains the article for building a 10 meter FRACTAL 2 or 3 element quad. Does anybody have a copy? 73's de Howard W3CQH From fortra at siol.net Mon Nov 16 14:39:30 2009 From: fortra at siol.net (Fortra) Date: Mon, 16 Nov 2009 23:39:30 +0100 Subject: [Antennaware] [Antennas] FRACTAL References: Message-ID: Hi Howard, using bit of my grey memory, that was probably series of articles in Communication Quarterly, by Chip Cohen, erghh the cal was N1......... I do have some magazines at disposal... Let me know, Best regards, Nermin S58DX ----- Original Message ----- From: "Howard W3CQH" To: "antennaware" ; "antennas" Sent: Monday, November 16, 2009 11:32 PM Subject: [Antennas] FRACTAL > With my chemo brain, I don't remember if I asked this question of the > groups > before. > > I am looking to buy a back issue of 73' magazine that contains the article > for building a 10 meter FRACTAL 2 or 3 element quad. > > Does anybody have a copy? > > 73's de Howard W3CQH > > ______________________________________________________________ > Antennas mailing list > Home: http://mailman.qth.net/mailman/listinfo/antennas > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Antennas at mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > From K1to at aol.com Tue Nov 17 19:48:34 2009 From: K1to at aol.com (K1to at aol.com) Date: Tue, 17 Nov 2009 22:48:34 EST Subject: [Antennaware] 3 element sideways vees - coax lengths? Message-ID: Design criteria: - 3 inverted vee elements, standard #14 or #12 insulated wire fed in the middle - Ground the unused 2 elements. A friend advises that especially here in FL that "floating" the unused elements will allow them to build up a charge, thus attracting lightning, so I should ground them instead. - Mount on an 87' tower that also has 5 HF Yagis on it. Guys are broken up with insulators. The downside of this is that the tower is a few feet short for allowing the vees to have the ideal included angle of 90 deg. - Use RG8X Mini for the feedlines to the switch box, along with the K3LR method of beads over a 14" section of thin coax at each feedpoint. I downloaded the demo version of EZNEC last night and enjoyed learning it tremendously. Wow, Roy -- what a full-functioned app! Anyway, the learning curve for entering the wires was not bad at all and I soon had the 3 vees in their sideways positions around the center, all fed in the middle. But as soon as I got to the Holy Grail problem of how long to make the feedlines, I hit my roadblock and don't know how to proceed. Here's what I've found published to date: - K3LR/WA3FET/K3LC design uses 4 sideways vees, floats the unused ones (does that matter?), and uses 153.45 degrees of feedline on each element. Their ELNEC design was quite precise and thorough. Circa 1992. Full article in Antenna Compendium Vol 4. See p.11 in particular. - K1WA 5L half-wave sloper array uses 135 deg of feedline and opens the unused lines. This design goes back to the '70s and was published in many ARRL Antenna Books. - W7LR built a 4L 40 array and also concluded that using 135 deg was correct. See Feb 1995 QST - Tech Correspondence. Side note - RG8X VF is listed as 0.75 and 0.78 in various places. This is trivial, since it just gives a starting place from which to trim more precisely. I'm grateful for any input and assistance on this and hope it's a worthwhile pursuit vs. just separating the flys*** from the pepper! 73, Dan, K1TO From k9ay at k9ay.com Wed Nov 18 07:00:59 2009 From: k9ay at k9ay.com (K9AY) Date: Wed, 18 Nov 2009 09:00:59 -0600 Subject: [Antennaware] 3 element sideways vees - coax lengths? References: Message-ID: <7713DB5C5FAD43D38DE50178E5F1CBA2@SUMMIT1> Dan, You can examine the stub-tuned reflector behavior using the EZNEC Transmission Line feature. The K3LR et al approach looks best to me, with the reflectors tuned for maximum smoke, but there are enough variables in a practical installation that might make it hard to detect the extra few dB F/B or tenths of a dB gain over the other designs. As you work on this, remember the law of diminishing returns (speaking from experience): If an array has a modeled gain of 4 dB, you will get 3 dB easily, then 3.5 dB with some careful additional work -- getting all 4 dB takes some combination of skill, luck and preseverance. Some guys don't do perseverance, and are quite happy with 3.5 dB. 73, Gary K9AY > Design criteria: > - 3 inverted vee elements, standard #14 or #12 insulated wire fed in the > middle > - Ground the unused 2 elements. A friend advises that especially here in > FL that "floating" the unused elements will allow them to build up a > charge, > thus attracting lightning, so I should ground them instead. > - Mount on an 87' tower that also has 5 HF Yagis on it. Guys are broken > up with insulators. The downside of this is that the tower is a few feet > short for allowing the vees to have the ideal included angle of 90 deg. > - Use RG8X Mini for the feedlines to the switch box, along with the K3LR > method of beads over a 14" section of thin coax at each feedpoint. > > I downloaded the demo version of EZNEC last night and enjoyed learning it > tremendously. Wow, Roy -- what a full-functioned app! Anyway, the > learning curve for entering the wires was not bad at all and I soon had > the 3 vees > in their sideways positions around the center, all fed in the middle. > > But as soon as I got to the Holy Grail problem of how long to make the > feedlines, I hit my roadblock and don't know how to proceed. > > Here's what I've found published to date: > - K3LR/WA3FET/K3LC design uses 4 sideways vees, floats the unused ones > (does that matter?), and uses 153.45 degrees of feedline on each element. > Their ELNEC design was quite precise and thorough. Circa 1992. Full > article > in Antenna Compendium Vol 4. See p.11 in particular. > - K1WA 5L half-wave sloper array uses 135 deg of feedline and opens the > unused lines. This design goes back to the '70s and was published in many > ARRL Antenna Books. > - W7LR built a 4L 40 array and also concluded that using 135 deg was > correct. See Feb 1995 QST - Tech Correspondence. > > Side note - RG8X VF is listed as 0.75 and 0.78 in various places. This > is > trivial, since it just gives a starting place from which to trim more > precisely. > > I'm grateful for any input and assistance on this and hope it's a > worthwhile pursuit vs. just separating the flys*** from the pepper! > > 73, Dan, K1TO From aa4nu at ix.netcom.com Wed Nov 18 21:10:52 2009 From: aa4nu at ix.netcom.com (Billy Cox) Date: Thu, 19 Nov 2009 05:10:52 -0000 Subject: [Antennaware] Jack Louthan, N5KT Memorial Service - Lexington, TX References: <7CEAE77D5D42485181FA0D43DB24BD63@pcb2> Message-ID: <5A6BFF661BB84FA88F5EB92A4A9C012D@pcb2> Recently the sad news was posted concerning the passing of fellow ham and author of Antenna Model software, Jack Louthan, N5KT. The family is having a memorial service for Jack next Monday, November 23rd, 12:00 PM at the Methodist Church in Lexington, TX and they would like to invite those who knew Jack to please attend. For directions: http://www.lexingtonumc.org/templates/System/details.asp?id=34405&PID=335831 Also the family after much diligence has decided to close out Teri Software and the Antenna Model software due to the lack of the source code. The website is now closed. Thanks for passing this information along to anyone else who knew Jack, N5KT. 73 de Billy, AA4NU ... on behalf of their family members. From n6ry at arrl.net Fri Nov 20 11:06:04 2009 From: n6ry at arrl.net (Terry Conboy) Date: Fri, 20 Nov 2009 11:06:04 -0800 Subject: [Antennaware] 3 element sideways vees - coax lengths? In-Reply-To: References: Message-ID: <4B06E89C.3090000@arrl.net> The demo version of EZNEC, with its limit of 20 segments, won't be too accurate for this array. At a minimum, you should use 10 segments per half-wavelength, so a 3-element array needs 30 segments just for the three vee elements, and preferably more for best accuracy. In addition, since the tower (top loaded by HF yagis) is between the vee elements, it really needs to be included in the model. The presence of the tower MIGHT be a non-issue, but it's really hard to tell without modeling it. Of course, one of the main benefits of modeling is to allow you to adjust things like the length of the transmission lines to tweak the array for your particular installation. What was optimum for the designs that you mention may not be the best at your site (tower a little too short, etc.). Whether or not floating the vees will attract more lightning, there's no question that if the elements charge to a high enough voltage, you can get noisy, if not damaging, arcing at inconvenient locations. Perhaps using 100k ohm resistors from both conductors of the element feedlines to ground is a workable approach, since you need to avoid shorting the line inputs. Also, if the shields of the feedlines are DC grounded for lightning, you may need to choke them for RF to avoid pattern distortion, if the design does not already do so. For completeness, the shields of the feedlines (with or without chokes) should be included in the model as a "physical" conductor (with near unity velocity factor), since the transmission line models in EZNEC are "virtual" or mathematical models of the transmission line differential-mode behavior only. 73, Terry N6RY On 2009-11-17 7:48 PM, K1to at aol.com wrote: > Design criteria: > - 3 inverted vee elements, standard #14 or #12 insulated wire fed in the > middle > - Ground the unused 2 elements. A friend advises that especially here in > FL that "floating" the unused elements will allow them to build up a charge, > thus attracting lightning, so I should ground them instead. > - Mount on an 87' tower that also has 5 HF Yagis on it. Guys are broken > up with insulators. The downside of this is that the tower is a few feet > short for allowing the vees to have the ideal included angle of 90 deg. > - Use RG8X Mini for the feedlines to the switch box, along with the K3LR > method of beads over a 14" section of thin coax at each feedpoint. > > I downloaded the demo version of EZNEC last night and enjoyed learning it > tremendously. Wow, Roy -- what a full-functioned app! Anyway, the > learning curve for entering the wires was not bad at all and I soon had the 3 vees > in their sideways positions around the center, all fed in the middle. > > But as soon as I got to the Holy Grail problem of how long to make the > feedlines, I hit my roadblock and don't know how to proceed. > > Here's what I've found published to date: > - K3LR/WA3FET/K3LC design uses 4 sideways vees, floats the unused ones > (does that matter?), and uses 153.45 degrees of feedline on each element. > Their ELNEC design was quite precise and thorough. Circa 1992. Full article > in Antenna Compendium Vol 4. See p.11 in particular. > - K1WA 5L half-wave sloper array uses 135 deg of feedline and opens the > unused lines. This design goes back to the '70s and was published in many > ARRL Antenna Books. > - W7LR built a 4L 40 array and also concluded that using 135 deg was > correct. See Feb 1995 QST - Tech Correspondence. > > Side note - RG8X VF is listed as 0.75 and 0.78 in various places. This is > trivial, since it just gives a starting place from which to trim more > precisely. > > 73, Dan, K1TO > >