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Tom Donaly wrote:
Cecil Moore wrote: Tom Donaly wrote: How do you know it's a "pure cosine wave," Cecil? Because Kraus says so? That's interesting. It means we don't need to use NEC any more. As I said previously, it's only a pure cosine wave for a thin-wire dipole. NEC handles more than thin-wire dipoles. The coil adds a bulge to the thin-wire cosine wave but the overall envelope is clearly visible. -- 73, Cecil http://www.qsl.net/w5dxp |
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Tom Ring wrote:
Richard Clark wrote: Hi Tom, If the mood strikes me, I will see how much effort it takes to blow away his "efficient" antenna. Seeing how he has no answers for its construction, I can easily impose my own choices like an high E piano string radiator mid loaded with a squirrel cage over a radial field of rusting springs from a burnt-out mattress. There should be room for improvement over that using a coat hanger with distributed loads of barn nails over the roof of a 1948 Hudson. 73's Richard Clark, KB7QHC I would prefer a radiator made from half inch PVC filled with a dilute sodium chloride solution. If you put a valve at the bottom, it's a snap to adjust resonance. tom K0TAR Have you tried beer? 73, Tom Donaly, KA6RUH |
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I'd guess that Reg would use wine.
Cheers, another of the Toms (Now if W8JI will just add something to this subthread, we'll have four of us in a row...) |
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Tom Donaly wrote:
I would prefer a radiator made from half inch PVC filled with a dilute sodium chloride solution. If you put a valve at the bottom, it's a snap to adjust resonance. tom K0TAR Have you tried beer? 73, Tom Donaly, KA6RUH What!!?? That would be a waste of beer. Well, unless it was Budweiser. tom K0TAR |
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Tom Ring wrote:
Tom Donaly wrote: I would prefer a radiator made from half inch PVC filled with a dilute sodium chloride solution. If you put a valve at the bottom, it's a snap to adjust resonance. tom K0TAR Have you tried beer? 73, Tom Donaly, KA6RUH What!!?? That would be a waste of beer. Well, unless it was Budweiser. tom K0TAR What is the bulk conductivity of 'Bud'? How does the bulk conductivity differ from other Beers? [I am a non drinker] |
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"Tom Ring" wrote in message .. . Tom Donaly wrote: I would prefer a radiator made from half inch PVC filled with a dilute sodium chloride solution. If you put a valve at the bottom, it's a snap to adjust resonance. tom K0TAR Have you tried beer? 73, Tom Donaly, KA6RUH What!!?? That would be a waste of beer. Well, unless it was Budweiser. tom K0TAR finally someone said something that makes sense in this thread... but no one has addressed my original question directly... but i guess that is par for the course in here when this group gets wound up, everyone goes off on their own little tangent and starts attacking each other. |
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Tom, K7ITM wrote:
"(Now if W8JI will just add something to this subthread, we`ll have four of us in a row---)" Like the beat, beat, beat of a tom-tom--- No, that`s the wrong song. It`s the one Merv Griffen sang with the Freddy Martin Orchestra: "I`ve got a loverly bunch of coconuts. There they are all standing in a row. Large ones, small ones, some as big as your `ead, Give `em a twist, a flick of your wrist, that`s wot the showman said." Best regards, Richard Harrison, KB5WZI |
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Dave wrote: finally someone said something that makes sense in this thread... but no one has addressed my original question directly... but i guess that is par for the course in here when this group gets wound up, everyone goes off on their own little tangent and starts attacking each other. I tried to, but I see it did no good at all. I have a Force 12 80 and 40 meter linear loaded Yagi. The Q of the loading sections are terrible. They are thin aluminum wire of some sort of alloy that makes them hard. For the typical reactances produced by that loading system Q (reactance over ESR) is well in the sub-100 range. That's why you can take even a fairly poor loading coil, replace the linear loading, and have the same perfromance. Or you can make a good coil, like airdux or BW stock with number 12-14 wire, and make the antenna work better (IF you can keep it from falling apart in the wind). The results of linear loading depends on where the linear loading is installed and how it is constructed, but the general rule is if you take the very same size and material conductors and wind a coil it will work better. Now I suppose we can talk about UHF antennas, 1/2 inch copper tubing stubs, Cecil's imaginary reflected waves, quote Harrison's book collection.....but that's how the Force 12 linear loaded 80 and 40 meter antennas I have work. That's why they are laying in a pile with waddled out holes near the rivets and all that lossy linear loading wire wrapped up in a ball, waiting the be rebuilt into good antennas. 73 Tom |
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Dave wrote:
What!!?? That would be a waste of beer. Well, unless it was Budweiser. tom K0TAR What is the bulk conductivity of 'Bud'? How does the bulk conductivity differ from other Beers? [I am a non drinker] Well, you can't waste Bud. For those that appreciate real beers and lagers, Budweiser is universally shunned. One batch at the factory, add preservatives, flavor enhancers, artificial flavorings, and voila! You have 10 different kinds of Bud. Or so I've heard. ;) I'm not sure about the conductivity. It might be worth buying a single to test. tom K0TAR |
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Yuri Blanarovich wrote:
"Richard Clark" wrote How much better? This sounds like a fractal sales pitch. Your HOW MUCH is getting a bit TOO MUCH! Comparing this to fractal sales pitch??? That is TOO MUCH! He's right, Richard. That was an awfully low blow. |
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On 20 Apr 2006 06:57:31 -0700, "Bill" wrote:
Yuri Blanarovich wrote: "Richard Clark" wrote How much better? This sounds like a fractal sales pitch. Your HOW MUCH is getting a bit TOO MUCH! Comparing this to fractal sales pitch??? That is TOO MUCH! He's right, Richard. That was an awfully low blow. Yeah, I suppose I should apologize to the fractal crowd. |
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Tom Ring wrote:
Tom Donaly wrote: I would prefer a radiator made from half inch PVC filled with a dilute sodium chloride solution. If you put a valve at the bottom, it's a snap to adjust resonance. tom K0TAR Have you tried beer? 73, Tom Donaly, KA6RUH What!!?? That would be a waste of beer. Well, unless it was Budweiser. Is there a beer called Budweiser now? Hopefully one to replace that old PeeWaa that was sold under the same name! ;^) darn stuff could give me a headache and make me queasy after one can..... ick. - 73 de Mike KB3EIA - |
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wrote in message oups.com... Dave wrote: finally someone said something that makes sense in this thread... but no one has addressed my original question directly... but i guess that is par for the course in here when this group gets wound up, everyone goes off on their own little tangent and starts attacking each other. I tried to, but I see it did no good at all. I have a Force 12 80 and 40 meter linear loaded Yagi. The Q of the loading sections are terrible. They are thin aluminum wire of some sort of alloy that makes them hard. For the typical reactances produced by that loading system Q (reactance over ESR) is well in the sub-100 range. That's why you can take even a fairly poor loading coil, replace the linear loading, and have the same perfromance. Or you can make a good coil, like airdux or BW stock with number 12-14 wire, and make the antenna work better (IF you can keep it from falling apart in the wind). The results of linear loading depends on where the linear loading is installed and how it is constructed, but the general rule is if you take the very same size and material conductors and wind a coil it will work better. Now I suppose we can talk about UHF antennas, 1/2 inch copper tubing stubs, Cecil's imaginary reflected waves, quote Harrison's book collection.....but that's how the Force 12 linear loaded 80 and 40 meter antennas I have work. That's why they are laying in a pile with waddled out holes near the rivets and all that lossy linear loading wire wrapped up in a ball, waiting the be rebuilt into good antennas. 73 Tom so why would a company like m2 go with linear loading over the much simpler to build coil? and how in the world do you measure the Q of the loading section when it is a large percentage of the size of the element? Does Q even really mean anything in a system that is radiating? Since some of the energy is being radiated along the length of the loading segment i would expect it to look very lossy compared to a small coil. |
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On Thu, 20 Apr 2006 21:38:13 -0000, "Dave" wrote:
so why would a company like m2 go with linear loading over the much simpler to build coil? There's no point in explaining market positioning in technical terms, because they often contradict each other. In other words, the profit motive does not have to make sense. and how in the world do you measure the Q of the loading section when it is a large percentage of the size of the element? Why would that be difficult? Does Q even really mean anything in a system that is radiating? It does if you want to use it in a trap. Since some of the energy is being radiated along the length of the loading segment i would expect it to look very lossy compared to a small coil. Good point. The only real issue at hand is IČ · Ohmic Loss 73's Richard Clark, KB7QHC |
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So Dave, have you built a NEC model of the antenna? Do you know that
the loading stub really has unequal currents on its two legs? Since that current is fairly close to the element itself, is the net current (the antenna current) on the stub in phase with or out of phase with the element current? What about the efficiency reported by NEC--if you use zero loss conductors versus the loss of the actual aluminum used in the antenna? From your description and the picture I found on the m2 website, it seems to me they are using the stub to make the antenna more mechanically robust than they could with no support. Whether it causes poor performance over what could be done with loading coils at the same positions as the stubs attach or not, I don't know, but a NEC simulation should shine some light on that question. You could start with a simple loaded dipole simulation, though that wouldn't tell the whole story. I do know that it's unfair to completely discount all stubs because people misuse them. Even if people regularly misuse them, it's no reason to discount them: it's reason to learn when they are appropriate and avoid misusing them. Though I don't know about the performance of your particular antenna, I do know that stubs can be very useful in providing reactances and resonators in a variety of applications, and I do know how to analyze situations in which I use them. Cheers, Tom |
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Dave wrote:
so why would a company like m2 go with linear loading over the much simpler to build coil? and how in the world do you measure the Q of the loading section when it is a large percentage of the size of the element? Does Q even really mean anything in a system that is radiating? Since some of the energy is being radiated along the length of the loading segment i would expect it to look very lossy compared to a small coil. One of the many very handy things about superposition is that it allows us to separate the radiating and transmission line properties of a linear loading section, analyze them separately, and add the results(*). So the Q of the linear loading section can be determined from its transmission line properties without radiation being involved. This can then be directly compared to the Q of a non-radiating inductor. As Tom W8JI has pointed out, the comparison is often not very favorable to the linear loaded antenna. You'd have to ask M2 why they do what they do. I suspect it's because a lot of amateurs don't understand the loss mechanisms involved, so are under the mistaken impression that linear loading is less lossy than a good inductor. And very few amateurs are capable of making even crudely accurate gain measurements or even comparisons so the vast majority would never know which is better. Smart companies give the customers what they want. (*) This is done by separating the currents on the two conductors into two sets of currents, common mode -- which radiate -- and differential, which don't. Roy Lewallen, W7EL |
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"Richard Clark" wrote in message ... On Thu, 20 Apr 2006 21:38:13 -0000, "Dave" wrote: so why would a company like m2 go with linear loading over the much simpler to build coil? There's no point in explaining market positioning in technical terms, because they often contradict each other. In other words, the profit motive does not have to make sense. reducing cost is a big part of business also, why produce a more complex and more expensive antenna if you could sell the same performance with a simpler design? after all, hams are generally cheap. and how in the world do you measure the Q of the loading section when it is a large percentage of the size of the element? Why would that be difficult? where do you connect your probes? and what are you actually measuring? since some of the energy is being radiated in between any two points where you could connect probes or measure currents the thing you are measuring would exhibit a more resistive (read VERY lossy) characteristic than a small coil you would put in the 3" gap that the linear loading segment spans where it connects to the middle of the element. and since the linear loading rods are not that far from the element itself they will couple strongly to the inner part of the element. Does Q even really mean anything in a system that is radiating? It does if you want to use it in a trap. its not a 'trap' its a loading section, meant to make a slightly shorter than 1/2 wave element resonant. high Q for a trap makes sense, not for a loading section like this. i think if you base the efficacy of the loading capability on some notion of Q it will likely be misleading. a better measure would likely be a field strength comparison. Since some of the energy is being radiated along the length of the loading segment i would expect it to look very lossy compared to a small coil. Good point. The only real issue at hand is IČ · Ohmic Loss and using relatively large diameter aluminum rod likely has less loss than a wound coil. 73's Richard Clark, KB7QHC |
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On Thu, 20 Apr 2006 23:11:53 -0000, "Dave" wrote:
"Richard Clark" wrote in message .. . On Thu, 20 Apr 2006 21:38:13 -0000, "Dave" wrote: so why would a company like m2 go with linear loading over the much simpler to build coil? There's no point in explaining market positioning in technical terms, because they often contradict each other. In other words, the profit motive does not have to make sense. reducing cost is a big part of business also, why produce a more complex and more expensive antenna if you could sell the same performance with a simpler design? after all, hams are generally cheap. You are confusing a direct correlation between cost and price. Marketing and demand that rises from marketing determines price, not cost. Hams pay price which is in excess of cost. This is proven everyday when they pay for a pre-fab dipole made of two pieces of wire and three insulators. You don't think they are paying cost for that alone do you? If so, they would buy two pieces of wire and three insulators instead. The profit motive does not have to make sense. and how in the world do you measure the Q of the loading section when it is a large percentage of the size of the element? Why would that be difficult? where do you connect your probes? At the source where loss counts. There is no way you are going to measure unloaded Q if that is your goal - it doesn't matter that much anyway unless it is for a trap. I haven't come across any distributed load traps unless someone wants to stretch meaning to include resonant lines. Even then, the same answer applies. and what are you actually measuring? Q, what else? since some of the energy is being radiated in between any two points where you could connect probes or measure currents the thing you are measuring would exhibit a more resistive (read VERY lossy) characteristic than a small coil you would put in the 3" gap that the linear loading segment spans where it connects to the middle of the element. and since the linear loading rods are not that far from the element itself they will couple strongly to the inner part of the element. Ummm, is this a problem? If you want to measure Q and put it in a bottle, perhaps it is. Does Q even really mean anything in a system that is radiating? It does if you want to use it in a trap. its not a 'trap' its a loading section, meant to make a slightly shorter than 1/2 wave element resonant. high Q for a trap makes sense, not for a loading section like this. i think if you base the efficacy of the loading capability on some notion of Q it will likely be misleading. a better measure would likely be a field strength comparison. Aside from the difficult language, you are not going to find a scintilla's worth of difference in what you propose to do with an FSM. It serves the purpose, easily. As for Q, you need to distinguish between loaded and unloaded Q. Next, you need to put a metric on what you mean by "high" Q. This is because you are probably not going to measure anything higher than 8 to 12 for a "slightly shorter than 1/2 wave" antenna. I would find it remarkable if the unloaded Q of any load would give you something as bad as a Q in the 20s or 30s. and using relatively large diameter aluminum rod likely has less loss than a wound coil. To say the least, but again, anyone can conspire to fail magnificently. 73's Richard Clark, KB7QHC |
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Dave wrote: so why would a company like m2 go with linear loading over the much simpler to build coil? Marketing, marketing, and marketing. Manufacturers have done an excellent job making everyone think traps are lossy and coils are bad. Some companies sell things significantly worse than what they say is "bad". One company uses a length of small coaxial line to provide a reactance loading their antenna to 80 meters, even though a piece of doorbell wire on a toilet paper tube would have less series resistance for the same reactance. Another one markets an antenna they say uses "resonators" instead of "lossy traps", but when you analyze the resonator it is actually just a self-resonant coil used as a trap, and that makes ESR terrible compared to some of the poorest L/C traps we could build. Linear loading is just another ploy. It lets them say "no lossy coils" when in effect what you have done is stretch a coil into an elongated single turn. When you do that you lose the advantage of mutual coupling aiding in reactance, so you have to increase conductor length to get the same reactance. A longer current path means more resistance. Worse yet, the stub places strong electric fields between two conductors (increases capaciatnce shunting the inductance), and that increases circulating currents that do nothing but heat the stub while decreasing bandwidth. Linear loading is exactly like doing everything we don't want to do to an inductor...but with one exception. The sole exception is a slight imbalance in currents allows the stub to radiate a little bit, and that radiation has the overall effect of allowing the linear loading to move the effective position of the load insertion to a DIFFERENT location than the place where the element is insulated. Say we have a 50 foot long element insulated 12.5 feet from the boom on each side. If we added linear loading with the stub extended OUTWARDS from that insulator it would look like we really inserted the loading a bit further out on the element than the point where the element is actually broken with an insulator. That can be an advantage because EFFECTIVE current distribution, the vector sum of current that actually causes radiation from the stub and element combination, would be more uniform over distance. We would effectively have more ampere-feet, and slightly higher radiation resistance. On the other hand it is just as easy, when we don't understand how the antenna works, to screw up and fold the loading stub inwards from the element insulator and move the effective point where the loading is added closer to the boom. That's why I say it is a soup of things going on, and the results can be not as bad as other cases. The general rule is, however, anything we can do with a linear loading system we can do better with a coil. Sometimes a little better, sometimes a lot better. and how in the world do you measure the Q of the loading section when it is a large percentage of the size of the element? Substitution and measurement of changes in feedpoint and radiation charcteristics, formulas to cross check, and dorect measurements of how the stub itself behaves when balanced. Does Q even really mean anything in a system that is radiating? That's why I defined Q as reactance over ESR, and not the less useful measurement of bandwidth. When the series resistance increases for a given reactance, you might as well use the loading system with less series resistance for the same reactance. That would be an inductor of proper form factor. Since some of the energy is being radiated along the length of the loading segment i would expect it to look very lossy compared to a small coil. .....but that radiation does nothing useful, except modify the effective location where the equivalent lumped load is placed. It doesn't magically give you something that would otherwise turn to nothing. I think the picture in your mind is remotely like the seriously flawed but somewhat popular idea that a folded element has increased efficiency from increased radiation resistance. 100 feet of wire in a 50 foot linear spatial area is still just a 50 foot antenna. All you can do is shuffle the effective current distribution around a bit, you can't make it behave like it is longer than 50 feet, and a coil will do the same thing for shuffling current as a linear loading system. All of this aside, the only thing that matters is how happy the antenna makes people. Doesn't matter that my dipole beats a linear loaded two element 80 meter Yagi. The yagi impresses people more. My own personal choice is to use a dipole on the air, but to show people visiting that I have a 2 element (linear loaded) Yagi. 73 Tom |
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"Dave" wrote in message
... wrote in message oups.com... Dave wrote: finally someone said something that makes sense in this thread... but no one has addressed my original question directly... but i guess that is par for the course in here when this group gets wound up, everyone goes off on their own little tangent and starts attacking each other. I tried to, but I see it did no good at all. I have a Force 12 80 and 40 meter linear loaded Yagi. The Q of the loading sections are terrible. They are thin aluminum wire of some sort of alloy that makes them hard. For the typical reactances produced by that loading system Q (reactance over ESR) is well in the sub-100 range. That's why you can take even a fairly poor loading coil, replace the linear loading, and have the same perfromance. Or you can make a good coil, like airdux or BW stock with number 12-14 wire, and make the antenna work better (IF you can keep it from falling apart in the wind). The results of linear loading depends on where the linear loading is installed and how it is constructed, but the general rule is if you take the very same size and material conductors and wind a coil it will work better. Now I suppose we can talk about UHF antennas, 1/2 inch copper tubing stubs, Cecil's imaginary reflected waves, quote Harrison's book collection.....but that's how the Force 12 linear loaded 80 and 40 meter antennas I have work. That's why they are laying in a pile with waddled out holes near the rivets and all that lossy linear loading wire wrapped up in a ball, waiting the be rebuilt into good antennas. 73 Tom so why would a company like m2 go with linear loading over the much simpler to build coil? and how in the world do you measure the Q of the loading section when it is a large percentage of the size of the element? Does Q even really mean anything in a system that is radiating? Since some of the energy is being radiated along the length of the loading segment i would expect it to look very lossy compared to a small coil. Dave, it boils down to the "problem" we were rehashing here - distribution of current along the antenna element. I tried to highlight that, but it gets lost in the "contributions" of the "same current worshippers". If you would model loaded element with 1. lumped inductance, 2. real solenoid and 3. loading stub - wires folded back onto element, you would see the variations of current distribution along the element and its effect on the design or optimization of multielement Yagi (cancellation in overlaps). The reason why antenna manufacturers used loading stubs to shorten the elements, was the idea that it would be less loss (it's "just" a wire) and would be more efficient than "some" lossy coil. You hardly find commercial loaded Yagi with coils as a loading element. They all used "nice, efficient" loading wires until W6 - I forgot the call, wasn't happy with performance of his 80m KLM loaded Yagi, replaced the "efficient" loading stubs with good quality coils and found that antenna performed much better. Better gain, better pattern, F/B (Richard can search for that "no good" article in CQ Mag. and query them). Few other hams did it too later and found the same. This is another proof of difference in performance when considering the proper loading and proper treatment of load in the standing wave (antenna) environment. The effect gets magnified in multielement arrays and has significant impact on the pattern and F/B. This is why we are arguing about proper treatment of the current distribution along the loaded element. How can it be the same in a coil, when it is demonstratively different in the loading stub (EZNEC shows THAT). When you have "wire" folded on itself three times and affecting currents (cancellation) along them - it gets worse than just current drop along the loading coil. The unbelievers would try to tell you that there can't be drop of current along the coil, much less along the loading stubs (it's just a piece of wire), but if you consider standing wave environment along the antenna element, then it all becomes clear and explains the behavior of various loading elements, current distribution in them and effect on the element and array. So replacing loading stubs with good quality coils WILL improve the performance of loaded Yagi, gain and especially give you better pattern and F/B. The same goes for Beta match at the center of element as used by i.e. Hy-Gain 402BA, replace it with few turns of copper tubing to get 50 ohm match to the coax. Now there is good fiberglass tubing available that can be used for strong insulators and forms for the loading coils. Standby for W8JI mumbo-jumbo, bla, bla, bla.... he has to be the last standing "trutz" man! You can verify and decide. 73 Yuri, K3BU |
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On Thu, 20 Apr 2006 22:18:31 -0400, "Yuri Blanarovich"
wrote: Richard can search for that "no good" article in CQ Mag. and query them Hi Yuri, That's got to be a recommendation! You can't remember the particulars, you can't remember the name, and I have to carry your water. You sound like a Washington bureaucrat in the White House - "Trust me! I'm here to help you with your Social Security." [It will be made as easy as the new drug benefit.] Now THERE's a standard of efficiency and performance that has been "proven." ;-) 73's Richard Clark, KB7QHC |
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"Richard Clark" wrote in message ... On Thu, 20 Apr 2006 22:18:31 -0400, "Yuri Blanarovich" wrote: Richard can search for that "no good" article in CQ Mag. and query them Hi Yuri, That's got to be a recommendation! You can't remember the particulars, you can't remember the name, and I have to carry your water. You sound like a Washington bureaucrat in the White House - "Trust me! I'm here to help you with your Social Security." [It will be made as easy as the new drug benefit.] Now THERE's a standard of efficiency and performance that has been "proven." ;-) 73's Richard Clark, KB7QHC That's right, for me it was enough to remember the results. If you want more info, you can Google it or SeeeKeeew it. You ain't paying me and for free advice this should do it. If I wanted to get details and build the coils, I would dig for it. For now I have better idea for loaded loop antenna, so it is on the back burner. Now you are mixing Washington in addition to Fractals - not very good picture of your "fakultys" if you have to rely on social security. Any constructive ideas besides filibusters and "Bush- baaad"? Sayonara! 73 (doesn't need 's - they are included) - if I was nitpicker like you :-) Yuri, K3BU/m |
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On Thu, 20 Apr 2006 23:17:51 -0400, "Yuri Blanarovich"
wrote: That's right, for me it was enough to remember the results. Hi Yuri, Folks remember dreams pretty much in the same way. You wake up astonished with the revelation, and forget the details before you throw back the covers. 73's Richard Clark, KB7QHC |
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Michael Coslo wrote:
Is there a beer called Budweiser now? Hopefully one to replace that old PeeWaa that was sold under the same name! ;^) darn stuff could give me a headache and make me queasy after one can..... ick. - 73 de Mike KB3EIA - That's the additives. Lots of people get headaches from AB products. I'm not sure which additives might do it, but boss probably does. He is very much into making homebrew. Even has a kegging system. Odd as it may sound, the pumpkin beer he made last fall was absolutely delicious. tom K0TAR |
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"K7ITM" wrote in message oups.com... So Dave, have you built a NEC model of the antenna? Do you know that the loading stub really has unequal currents on its two legs? Since that current is fairly close to the element itself, is the net current (the antenna current) on the stub in phase with or out of phase with the element current? What about the efficiency reported by NEC--if you use zero loss conductors versus the loss of the actual aluminum used in the antenna? no, i don't own nec, and don't know enough about it's methods or limitations to trust just throwing together a model to play with on any free version i could get. i have done enough modelling professionally with tools like ansoft/maxwell (for quasi static e-fields), EMTP (for power line transients), TFlash (for lightning transients on power lines), Simulink and EASY5 (electro-mechanical control systems), and some other tools, that i know that if you don't know your tool and it's limitations that any result you generate is questionable. besides, i have enough other things to do this summer putting up new antennas and using them... not enough time to second guess every design out there, I made my choice and I'll take my chances... but the 40m4LLDD i put up last year at 105' seemed to work well over the winter, and much better than the 40-2cd it replaced.... (compared over almost a year now against another 40-2cd that hasn't been moved)... so now i'm replaceing the other 40-2cd with a second 40m4LLDD at 175'. if nothing else it will look impressive, and thats worth 3db or more in the operator's belief that they are loud. |
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