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#11
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Looking over the replies to this post makes me wonder where the helpful
ham hand is lurking these days. This poor guy just wants to know about plans and materials for an antenna to build and all but one reply tells him he doesn't want one or you should buy this one or he's stupid for considering one or I can get into this repeater with that antenna, bla, bla bla. It can be made with the same components as an SO-239 1/4 wave ground plane but with a little more wire with a cork screw turn at the bottom. Doesn't anyone have the simple plans for this guy? George Cronk wrote: Does anyone know where I can get plans for this antenna? Materials needed to build one? Thanks |
#12
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On Mon, 05 Apr 2004 00:54:06 GMT, Mike wrote:
Looking over the replies to this post makes me wonder where the helpful ham hand is lurking these days. This poor guy just wants to know about plans and materials for an antenna to build and all but one reply tells him he doesn't want one or you should buy this one or he's stupid for considering one or I can get into this repeater with that antenna, bla, bla bla. It can be made with the same components as an SO-239 1/4 wave ground plane but with a little more wire with a cork screw turn at the bottom. Doesn't anyone have the simple plans for this guy? George Cronk wrote: Does anyone know where I can get plans for this antenna? Materials needed to build one? Thanks Actually I do have plans for a colinear 5/8 over 5/8 2 meter antenna; all you'd have to do is omit the phasing coil and top radiator. This one is built from wire on an SO-239. To the original poster - I can scan the sketch & email it to you, let me know if you'd like that & it's a done deal. Howard KE6something or other |
#13
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"Dave VanHorn" wrote in message ...
"Mark Keith" wrote in message om... George Cronk wrote in message . 154.205... Does anyone know where I can get plans for this antenna? Materials needed to build one? Thanks You would be better off with a 1/4 wave ground plane on 2m. Seriously. And one of those can be as simple as five 19 inch pieces of wire and a So-239 connector. MK Why would he be better off with a 1/4 wave, with it's large vertical lobe? Cuz it's easier decoupled with it's 1/4 wave radials, and is less likely to have feedline radiation than the funky 5/8 antenna with 1/4 wave radials. In direct comparisons here, the 1/4 GP was a good bit better than the 5/8 with 1/4 radials. The maximum gain of an elevated 1/4 wave GP on 2m, mounted at 35 ft at the base, is appx 6.2 dbi at 3 degrees. The maximum gain of a 5/8 GP with horizontal 1/4 wave radials, at the same height, is about 4.7 dbi at the same angle. And this does not yet take into account any decoupling problems! If the feedline radiates, any gain on the horizon is likely lost as the pattern is skewed up off the horizon. The average 5/8 antenna is ruined by using 1/4 wave radials. A 5/8 should be paired with a mirror image 5/8 to function properly. IE: dual 5/8 collinear such as the isopole, etc... And decoupling must still be used even on those. I agree with one thing Richard said about height and a 1/4 wave..If you get the tip of the 1/4 GP at the same height as the tip of a tall dual 5/8 collinear, there is little real difference between the two. And the dual 5/8's collinear is better than a 5/8 GP. 2m is real critical as far as the low angles used, and also to the effects of feedline radiation lowering the gain at those low angles. Now on 10m, many times I do prefer a 5/8 GP over a 1/4 GP, but there the angles used are less critical. If your 5/8's works, I wouldn't worry much, but in comparing them in A/B tests, "at appx 35 ft" I've never seen a 5/8 GP with 1/4 radials beat a 1/4 wave GP with 1/4 radials. I once built a fancy 5/8 GP with a nice larson coil, lots of 1/4 wave radials, etc...Was a super dud...I tore it up the 1st day and went back to a 1/4 wave. The 1/4 wave was an average 3-4 S units better on local rptrs, and simplex. About the same difference as comparing a undecoupled ringo ranger, to a decoupled ringo ranger 2... MK |
#14
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Mike wrote in message .com...
Looking over the replies to this post makes me wonder where the helpful ham hand is lurking these days. This poor guy just wants to know about plans and materials for an antenna to build and all but one reply tells him he doesn't want one or you should buy this one or he's stupid for considering one or I can get into this repeater with that antenna, bla, bla bla. It can be made with the same components as an SO-239 1/4 wave ground plane but with a little more wire with a cork screw turn at the bottom. Doesn't anyone have the simple plans for this guy? Sure, if he really wants to use an inferior antenna, I can tell him how to build it. It's simple. A 5/8 wave radiator, and about 4-5 turns of coil on a one inch form for matching will get him fairly close. But I don't recommend one. You wouldn't get me running a 5/8 GP on 2m for anything. It's like G5RV's on 80m...They usually suck...So do most 5/8's GP's on 2m...:/ But don't take my word for it. Compare them with an antenna switch and see. The only time I ever see a 5/8's beat a 1/4 on 2m, is if they are nearly on the ground. And I think thats just a line of sight deal... MK |
#15
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![]() "Mark Keith" wrote in message om... "Dave VanHorn" wrote in message ... "Mark Keith" wrote in message om... George Cronk wrote in message . 154.205... Does anyone know where I can get plans for this antenna? Materials needed to build one? Thanks You would be better off with a 1/4 wave ground plane on 2m. Seriously. And one of those can be as simple as five 19 inch pieces of wire and a So-239 connector. MK Why would he be better off with a 1/4 wave, with it's large vertical lobe? Cuz it's easier decoupled with it's 1/4 wave radials, and is less likely to have feedline radiation than the funky 5/8 antenna with 1/4 wave radials. In direct comparisons here, the 1/4 GP was a good bit better than the 5/8 with 1/4 radials. Interesting. You obviously have developed a far superior measurement technique than most antenna engineering firms, and maybe even NIST. Your results disagree with pretty much everyone who measures antenna gain professionally, and the ARRL handbooks, but hey they must all be wrong then. Though it's entirely done in the HF spectrum, a pretty detailed analysis is presented he http://www.cebik.com/58-3.html A good ground, and cleaner near-field space, is easier to come by at VHF and UHF, so I would expect results to be somewhat better than what was seen here even at the high end of the HF spectrum. If you google a bit, you'll probably find some articles on converting a CB antenna to a 5/8 2 meter antenna. |
#16
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Dave VanHorn wrote,
lobe? Cuz it's easier decoupled with it's 1/4 wave radials, and is less likely to have feedline radiation than the funky 5/8 antenna with 1/4 wave radials. In direct comparisons here, the 1/4 GP was a good bit better than the 5/8 with 1/4 radials. Interesting. You obviously have developed a far superior measurement technique than most antenna engineering firms, and maybe even NIST. Your results disagree with pretty much everyone who measures antenna gain professionally, and the ARRL handbooks, but hey they must all be wrong then. Though it's entirely done in the HF spectrum, a pretty detailed analysis is presented he http://www.cebik.com/58-3.html A good ground, and cleaner near-field space, is easier to come by at VHF and UHF, so I would expect results to be somewhat better than what was seen here even at the high end of the HF spectrum. If you google a bit, you'll probably find some articles on converting a CB antenna to a 5/8 2 meter antenna. In volume 1 of the Antenna Compendium series is an article entitled "The 5/8-Wavelength Antenna Mystique" by Donald K. Reynolds, K7DBA. I don't think Reynolds would disagree with Mark too much. 73, Tom Donaly, KA6RUH |
#17
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"Dave VanHorn" wrote in message
Cuz it's easier decoupled with it's 1/4 wave radials, and is less likely to have feedline radiation than the funky 5/8 antenna with 1/4 wave radials. In direct comparisons here, the 1/4 GP was a good bit better than the 5/8 with 1/4 radials. Interesting. You obviously have developed a far superior measurement technique than most antenna engineering firms, and maybe even NIST. Maybe so if using a simple antenna switch to A/B test is superior... Your results disagree with pretty much everyone who measures antenna gain professionally, and the ARRL handbooks, but hey they must all be wrong then. No, they do NOT disagree with most who have a clue. BTW, those "results" I gave you with gain numbers were from modeling. Though it's entirely done in the HF spectrum, a pretty detailed analysis is presented he HF? Thats the problem....You can't apply the performance shown on HF, and expect it to pan out on 2m. The decoupling problem will rear it's head on VHF. http://www.cebik.com/58-3.html A good ground, and cleaner near-field space, is easier to come by at VHF and UHF, so I would expect results to be somewhat better than what was seen here even at the high end of the HF spectrum. A good ground is not the whole answer. Decoupling is more important at those higher frequencies. If you google a bit, you'll probably find some articles on converting a CB antenna to a 5/8 2 meter antenna. Why would I need to do that? I already done that before. I've built enough 5/8 antennas to choke a horse. Maybe two or three. Thats why I'm fairly comfortable with what I say. I'd like to ask one question. Have you ever actually compared the two types at the same time using a switch? MK |
#18
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"Dave VanHorn" wrote in message
If you google a bit, you'll probably find some articles on converting a CB antenna to a 5/8 2 meter antenna. One note...There is only one case on VHF where I often prefer a 5/8 over a 1/4 , and that is on a car when roof mounted. The 5/8 will usually "picket fence" less, if you are in an area that is all flat terrain. But as far as elevated ground planes at the house, I prefer the 1/4 wave anyday. If I use 5/8 elements at home, it will always be a dual 5/8 collinear of some type. Not a GP with 1/4 wave radials. MK |
#19
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![]() "Mark Keith" wrote in message om... "Dave VanHorn" wrote in message If you google a bit, you'll probably find some articles on converting a CB antenna to a 5/8 2 meter antenna. One note...There is only one case on VHF where I often prefer a 5/8 over a 1/4 , and that is on a car when roof mounted. The 5/8 will usually "picket fence" less, if you are in an area that is all flat terrain. And that's exactly where I use them. Not much problem with ground planes or decoupling. |
#20
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Hustler makes a 5/8 wave 2M antenna they call the SF-2. HRO sells them for
$14.95. At that price the only reason to make one is "for fun" but that's worthwhile. 73, K3DWW "George Cronk" wrote in message 54.205... Does anyone know where I can get plans for this antenna? Materials needed to build one? Thanks |
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