welcome to w2bri's magnetic loops欢迎来到w2bri的磁迴圈
magnetic loop antennas for hf高频磁性环形天线
magnetic loop antenna faq磁环路天线的常见问题
please read:请阅读:considering the controversy any ham antenna conversation can generate, i thought it was important for me to write down some of my opinions on and about magnetic loops. 考虑到任何含天线争议谈话产生的时候,我想这是重要,我写下我的一些看法和磁迴圈。people are going to ask these questions over and over again, so i might as well save them the trouble upfront. 人们要问这些问题了好多次了,所以我不妨保存他们的麻烦前期。some of these observations are based on real world testing, building, and daily use of many magnetic loop antennas. 其中的一些观测结果是基于真实世界的测试、建筑和日常使用的许多磁性环形天线。so please find this faq a resource for your exploration and in no way a dogmatic listing of ideas. 所以请找本faq资源为您的探索,决不是一个有教条的上市的想法。some of the information you find here is simply what i have found to be the case when tested by me. 一些资料,请点击此处就是我所发现的情况下做相应的测试时,在我旁边。i welcome questions, and i'll be happy to add information to the faq as it is relevant and meaningful. 我欢迎询问,并且我很乐意添加信息作为相关faq和深远的意义。this is a start.这是一个开始。
1. 1。what is a magnetic loop?什么是磁回路?
a magnetic loop or stl (small transmitting loop) is a large coil with a capacitor added to bring the system to resonance. 一个磁性的圈或stl(小传送环)是一种大型的线圈将电容器增加系统共振。it is unlike a large resonant loop (more common) in that the loop size is smaller than 1/4 wavelength and does not resonate on its own. 像一个大型谐振回路(更常见),小于环大小并不共振波长和对自己的。the loop is brought to resonance by attaching a capacitor to the two open ends of the loop. 回路中的共振附上了电容器两开完的循环。the loop is tuned by a changing the value of the capacitor. 调谐回路中的一个改变价值的电容器。an increase in capacitance will bring the resonance of the loop lower in frequency, a decrease in capacitance will make the loop resonate higher. 增加电容会带来的共鸣频率低,循环减少电容会使环共振更高。an excellent resource for more in depth information is the arrl antenna book, section 5 (there is a lot of good info, but don't believe everything you read!).一个很好的资源,为更深入的资料是arrl天线的书,第五节(许多有益的信息,但不要相信你读的每件事!)。
2. 2。how well does it perform compared to other antennas?它是如何执行相比其他天线吗?
a magnetic loop's performance seems to be dependent on construction, placement above ground, and other factors. 一个磁性环的表现似乎依赖于建筑、安置在地面上,和其他因素。a generalization of performance would place it a bit below that of a dipole, and in some instances exceeding the performance of a dipole. 一个泛化性能将把它有点之下,这是一个偶极子,在某些情况下的性能超过一个偶极子。it usually will far surpass the performance of most mobile antennas, and other compromise configurations (however, there are always exceptions).它通常会远远超过大多数手机天线的性能,其他的妥协方式(但是,总是有例外)。
3. 3。why do you build your loops as squares instead of circles or octagons? 为什么你建立你的;而不是圈、广场octagons吗?aren't circles more efficient?不是圈子更有效率呢?
yes, circles are more efficient, by about 10%! 是的,怪圈是更有效率,大约10% !but they are harder to make when your working with one or two inch copper. 但是他们很难使你的工作时,有一个或两个寸铜。i would rather just build the loop a little bigger to gain back the loss. 我宁愿只是建立循环重新获得更大的损失。for instance, according to ki6gd loop modeling software, it only takes a extra foot and half of circumference or an extra half inch of diameter of pipe to gain back the lost efficiency. 例如,根据ki6gd环建模软件,它只需要一个额外的脚和一半的周长或额外的半英寸直径的管道重新获得丢失的效率。also, squares are easier to make and have less solder joints than octagons.同时,方块比较容易制造不到比octagons焊点。
4. 4。is copper better than aluminum for loops?铜比铝循环吗?
absolutely and for the most part. 绝对的大部分。it has over a 20% difference in efficiency according to some modeling software. 它有超过20%的差异在效率根据一些建模软件。more efficiency equals more performance. 效率等于更多的性能。it's also a lot easier to solder, and can be found at your local hardware store. 这也是一个更容易焊接,可以发现在您当地的五金商店。however, aluminum is far lighter. 然而,铝是远轻。it's a trade-off. 这是一个妥协。i would hate to know what my 12 ft x 12 ft loop with 2 inch diameter pipe would weigh if it was made out of copper instead of aluminum. 我不想知道我12英尺x 12英尺2英寸直径的管道回路重如果它用铜代替铝。please remember, my aluminum loop works great.请记住,我的铝环伟大的作品。
5. 5。how important is loop circumference? 循环围有多重要?how important is the size of the conductor diameter?多么重要的尺寸导体直径吗?
loop circumference relates directly to efficiency and performance (also, loop image: see below). 环路围直接关系到效率和绩效(同时,环形象:见下文)。the larger the circumference of the loop, the better your loop will work -- however, if you exceed 1/4 wavelength, things seem to get mysterious. 大的圆周循环,循环将更好,你的工作——但是,如果你超过的波长,事情似乎变得神秘。it's a balance, i try to get about 85-90% of the wavelength in circumference, and that seems to be the magic number. 这是一个平衡,我努力让约85 - 90%的波长,在一个圆周里面,那好像是神奇的号码。however, i'm not making any definitive statements because i have found loops above 1/4 wavelength that seem to work well. 然而,我不做任何权威的陈述,因为我发现环似乎表明以上波长很好地工作。there are other factors that effect the total loop size, and that is loop pipe diameter. 还有其他因素影响总环大小,那就是循环管的直径。i have built loops that were 16 feet in circumference and made out of 2 inch copper. 我已经建造环的是16英尺,在一个圆周里面使用2英寸的铜。the loop worked poorly on 20 meters (where 16.5 feet would be 1/4 wavelength), and worked better on 40 meters. 循环不好工作20米(16.5英尺的地方将是的波长)和工作,更好的在40米。what i assume is that if you use pipe that exceeds a certain size, the total loop size (not circumference), but total loop image, in other words the electrical size is too big for the intended frequency -- maybe. 我以为是如果你使用管道超过一定规模,总环尺寸(不是周长),但总环形象,换句话说,电尺寸太大了特定的频率——也许。you end up exceeding the wavelength limit and the loop starts to self resonate (according to some people). 你最终超过极限及环波长开始自我共振(根据一些人)。i have built half inch copper 16 foot circumference loops that worked much better on 20 meters than the 2 inch copper version. 我已经建造16英尺半英寸铜环的工作周长比在20米比2寸铜的版本。so be careful when building your loop and understand that pipe diameter plays a part in its performance. 所以要小心当建立您的环和理解管道直径的演奏中扮演了一个角色。what i would propose is that my 80 meter loop that is 12 feet by 12 feet is in fact larger electrically (or in image) larger than its 48 feet circumference because of the 2 inch pipe size. 我要提出的是,我的80米环,是12英尺实际上是由12英尺大电(或在图像)大于其48英尺2英寸的周长由于管道尺寸。i believe that if i would have used smaller pipe, the loop would not have worked so well on 80 meters. 我相信如果我将使用较小的管道,循环就没有工作得很好在80米。this is conjecture. 这是猜测。i would compare this to the effect of a fat dipole or cage dipole. 我将把这个效应的一个胖偶极子或笼子偶极子。the thicker the diameter of the wire the shorter the length of the total dipole. 较厚的电线的直径长度越短的总偶极子。it seems to make sense that the thicker the diameter of the conductor, the larger the total loop image will appear electrically. 这似乎意义较厚的直径的导体、较大的形象将出现电总循环。however, one thing i and others have noticed is that if you build a loop for the low bands, make sure the pipe is thicker rather than thinner. 然而,有一件事我和其他人注意到的问题是:如果你建立了一个循环的低乐队,确保管道较厚而不是变薄。i would suggest two inches and above, this seems to deliver the best results.我建议2英寸以上,这似乎提供最好的结果。
6. 6。do i really need to solder or weld all the joints on a loop?我是否真的需要把所有接头焊缝焊或在一个回路?
according to almost all the literature i have seen on loops, all connections must be soldered or welded. 几乎所有的文学根据我看见了在循环、所有的连接必须焊接或焊接。please read on because i do not believe it's that simple. 请继续读下去,因为我不相信它是那么简单。it appears that mechanical connections create resistance in the conductor which cause major losses in efficiency. 看来机械连接导线创造阻力造成重大的损失效率。it is interesting to note that all the loop articles i have seen and read do not discuss mechanically built loops, only welded versions. 值得注意的是所有的环的文章我都见过。也读不讨论机械循环,只有建立焊接的版本。i myself have built both mechanical and soldered loops and have not found major variations in performance if the mechanical connections are well made. 我已经建造两个机械和焊接循环和没有发现大的变异机械连接性能很好。this is purely observational. 这是纯粹的观测。my 12 foot by 12 foot loop for 80 meters has no welded or soldered connections and works well from my daily observations and anecdotal evidence. 12英尺12脚环为80米没有焊接或焊接连接和作品在我日常的观察和证据。keep in mind, however, that each segment of pipe has a 3 inch taper that slides into the next pipe (and is then bolted together) -- so there is plenty of overlap for each connection. 但要记住,每一段管道有3英寸锥,幻灯片进入下一个水管(然后绑在一起——所以有足够的重叠,为每个连接。i have also built loops mechanically, tested them for some time, and then soldered them together to see if there would be a measurable change. 我也建环机械、测试他们一段时间,然后焊接在一起,看看会有显著的改变。as of yet, as long as the mechanical connections are well made, there seems to be no measurable difference. 但是,只要机械连接都是制作精良,似乎没有适度差异。these conclusions do not seem to correspond to the general literature of loop making, but i feel it is important to put this information out there for debate.这些结论似乎不符合一般文学回路制作,但是我觉得它是很重要的,把这个信息的争论。
7. 7。can i use regular air variables from an old transmatch for tuning?我可以用的空气从一个老transmatch变量为调整吗?
most loop literature would say that the wiper connections on commonly found air variables are too lossy. 大多数回路文学可以说器连接空气变量常见太耗。also voltage capacity is an issue. 也电压能力是一个问题。any capacitor used should be able to withstand high voltages in the 3-4kv range if you are running 50-100 watts. 使用任何电容器应能承受高电压范围在3-4kv如果你正在运行50-100瓦。if you are using welded stator or butterfly capacitors with a high enough voltage rating there should be no problem or significant losses. 如果你正在使用或蝴蝶电容器焊接定子足够高的额定电压不应该有任何问题或重大亏损。however, high voltage stator or butterfly capacitors with a large capacitive range usually cost about the same as a nice used jennings vacuum variable. 然而,高电压定子或蝴蝶电容器电容的大范围的成本通常大约相当于一好的二手詹宁斯真空变量。i personally use the vacuum variables. 我个人使用真空变量。a cheap alternative to expensive high voltage variables is the use of coax for monoband utility. 一个廉价的替代昂贵的高电压变量是使用同轴为monoband效用。take a good piece of coax, separate the braid from the conductor for a couple of inches and attach each side to each open end of the loop. 好好块哄,把辫子从几英寸导线并附上每面每一端开口的循环。use varying lengths of coax to create different capacitance values for tuning. 用不同长度的哄着创建不同调谐电容值。trim the coax till you reach your desired resonance. 修剪哄,直到你碰到你理想的共振。this works very well if you don't mind being stuck on one band. 这个工作很好,如果你不介意被困在一个乐队。you can also change the coaxial stubs when you want to change frequency pretty easily. 你也可以改变同轴【当你想要更换频率相当容易。i have heard opinions put forth that braid in coax is too lossy for good loop performance for capacitors, but i have not found this to be the case at all.我所听到的意见,提出在哄太耗编织良好的循环性能对于电容,但是我还没有发现这是这样的情况。
8. 8。how well does a loop made of coax work?请问如何由哄一个循环的工作吗?
when using coax, either the ground braid or the center conductor can be used. 当使用哄,无论是地上编织或中心导体都可以使用。unless you using one inch hardline the diameter of the braid is simply too small for high efficiency. 除非你用一英寸直径的强硬编织实在太过小,对效率高。have i tried it on rg-8u and other types of coax? 我试了一下rg-8u和其它类型的哄吗?yes. 是的。does it work well? 它是否效果好吗?in my opinion the answer is no. 在我看来,答案是否定的。one inch or even half inch copper pipe will work much much better. 一寸甚至半英寸铜管将工作非常非常好的”。i would not recommend this strategy at all since every experiment of this type yielded poorly performing loops. 我不建议这个策略在这种类型的,因为每一个实验产生的表演圈。差also, some opinions believe that the braid in coax is too lossy because it is not one piece of metal but strands of copper with minute gaps between the pieces introducing excessive losses. 另外,一些观点认为编织在哄太耗的,因为那不是一块金属,但是带有一股铜件间隙引入过度的损失。i cannot comment on this point.在这一点上,我不能说什么。
9. 9。how do you compare copper or aluminum strap to pipe?你怎么比较铜或铝带管道吗?
modeling software claims strap is equal to one half the size of full diameter pipe.建模软件声称皮带等于一个一半大小的全直径管道。
10. 10。does a loop have a gain pattern? 是否有一个获得一个循环模式?what does it look like? 那东西是什么样子?does it matter?这有关系吗?
a vertically positioned magnetic loop has a figure eight gain pattern along the plane of the loop itself. 一个垂直方向定位磁回路的身材沿平面八获得模式循环的本身。in other words, think of two donut shaped patterns radiating from the the vertical portion of each vertical side. 换句话说,认为两个油炸圈饼形模式从垂直部分辐射的每一个垂直的一面。this pattern creates a null where the two donuts meet in the center of the loop. 这个模式,创建一个空的地方遇见两圈中心的循环。so a loop with its vertical sides placed north and south, will radiate best north and south. 这样一个回路与它的侧面放置北部和南部,会辐射出最好的南北。the same is true if you rotate the loop east and west. 如果你也是同样的旋转环东面和西面。loops can be placed on rotors and the loop can be turned for best signal strength or it can be used to null out offensive interference. 循环可以放置和转子回路可以转最佳信号的强度或它可以用来空出进攻的干扰。magnetic loops also radiate rf at all angles, so they are well suited for both high and low angle reception and transmission. 磁力环圈也对所有角度的射频辐射,所以他们很适合这两个高、低角度的接待和传输。this is advantageous for both high angle nvis work, and dx. 这是两个高角度nvis便于工作,__。loops that are mounted horizontally radiate in an omnidirectional pattern and do not share the benefit of a vertical polarization. 环的安装在水平全方位辐射模式和做自己分内的垂直极化的好处的。i would recommend vertical placement.我想推荐垂直放置。
11. 11分。why are commercial loops so expensive?商业圈为什么这么贵?
magnetic loops require high voltage capacitors for more than qrp power level operation. 磁力环圈需要高电压超过qrp电容器功率水平运作。these capacitors tend to be very expensive. 电容器的往往是很昂贵的。a brand new jennings vacuum variable can cost at least five hundred dollars (they are a lot cheaper used). 一个全新的詹宁斯真空变量可以花至少五百美元(便宜得多采用)。high voltage stator and butterfly capacitors also cost a lot of money. 高电压定子和蝴蝶电容器也花很多钱。so the final product including the capacitor can be quite expensive. 因此,最终产品包括电容会很贵。also, commercial manufacturers desire to build the best possible loop, so they employ all welded construction on loop joints. 同时,商业制造商希望建立最好的循环,所以他们使用全焊接施工环线的关节。this also adds to the cost.这也增加了成本。
13. 13岁。do radials help?做radials帮助吗?
radials added to the ground feed of a loop is supposed to lower q and raise efficiency (see the arrl antenna book, section 5). radials饲料添加到地面循环被认为是低q和提高效率(参见第5章arrl天线的书)。i know this sounds anti intuitive, but i have tested this many times and it seems to be the case. 我知道这听起来反直觉的,但是我已经测试了这个好多次了,这似乎是如此。the bandwidth of the loop opens up by about 10%, the efficiency seems to be raised (this is indicated by observations i have made in antenna feed arrangement in relation to loss), but i have not noticed improved performance. 环路带宽的打开了大约10%,似乎是提高效率(这是观测结果表明在天线与饲料安排损失),但我没有注意到绩效的提升。it would seem to make sense that with higher efficiency there be better performance, but i have not seen a measurable difference. 它会合情合理,生产效率较高有更好的表现,但是我还没有看到一个适度差异。this needs more testing. 这需要更多的测试。when possible, i do add radials. 如果可能的话,我不要添加radials。radials do not need to be cut to operating frequency, but can simply be twice the diameter of the loop.radials不需要切割操作的频率,但也只是两次直径的循环。
14. 14。what if i exceed 1/4 wavelength circumference will the loop still work?如果我超过的波长围循环仍然起作用?
yes. 是的。i once believed that it does not seem to work as well as a loop of 1/4 wavelength circumference. 我曾经认为,看来不是工作以及环二自由度波长周长。testing this theory now leads me to other conclusions, as larger loops seem to work better in some instances.测试这一理论现在引领我到其他结论,因为大型循环似乎更好的工作在某些情况下。
15. 15。are loops quieter than other antennas?是较其它天线环吗?
a lot of literature on loops make this claim. 大量的文献,对这种说法回路。i have noticed that i do hear less noise than hams i am talking on many occasions. 我已经注意到我听到噪音低比我所谈论的火腿在许多场合。they complain about it and i don't hear what they hear . 他们抱怨它,我不听他们听见。but remember, they may be using better antennas which have more gain and usually have more noise as well. 但是记住,他们可能会使用更好的天线增益与,通常有更大的噪音。another factor could be the high q of my loop acting as a filter for more broad band noise.另一个因素可能是高q值作为我的环路滤波器的更多的宽带噪声。