【火腿DIY】有才 | 美国小哥Scott 隐藏在天花板上的HF天线是咋样滴赶脚？
Simple DIY Stealth Apartment Antenna for 20m and 40m!
作者：Scott W Harden
编译：BG5WKP 朱轶
I have no money for a HF antenna, and even if I did my apartment complex wouldn’t allow it! This is my story, and while I’m no expert I hope that sharing my experience will help encourage others to try crazy things in the spirit of invention. A friend loaned me a Century 21 HF CW-only transceiver which puts out ~20W. As far as an antenna, I was limited to what I could build. I tried a bunch of different designs, including a trash-brew 40m base-loaded vertical, but it didn’t work that well. I found that a “contorted dipole” (I heard it’s officially called a zig-zag design) strung up on my ceiling works surprisingly well. I’ve only had it up a few days, but from Florida I’ve talked to New York on 40m at 20W and Maine on 20m using 20W. Keep in mind that I’m brand new to CW, and that 99% of the conversations out there are way too fast for me to copy, so my greatest limitation is finding a CQ slow enough that I can respond to it.
我买不起HF天线，即使买了，在公寓也没法架设。这就是我的故事，我不是专家但愿意分享我的经历以鼓励那些具有发明精神，勇于尝试疯狂事物的火腿。有个朋友借给我一台20瓦的21世纪HF CW收发信机，至于天线，条件所限没有办法架设。我尝试过一些设计，包括 trash-brew 40米段垂直天线，但是工作效果不好。后来，我发现弯曲偶极天线（官方说法是曲折天线）吊在天花板上可以工作良好，天线安装后几天，我从佛罗里达州在40米段用20W通联到了纽约州，用20米段20瓦通联到了马里兰州。要知道作为一个CW的新手，99%的通联对我而言都太快了，没法抄收。我仅仅能找到发报慢一点的电台进行回复。
The beauty of my antenna is four-fold. First, it’s super-cheap (a few bucks worth of parts). Second, it’s off the floor and out of the way (unlike my vertical). Third, it doesn’t require a tuner once it’s set up. Forth, it’s virtually invisible! Seriously, if you walk in my apartment you’d have no idea it’s there unless someone points it out. Check it out…
我的天线杰作有一下四点优势：
1、价格相当便宜，只有少部分零件需要钱
2、不像我的垂直天线一样，它不用落地，不会阻碍过道
3、一旦安装好就不在需要天调
4、这个几乎是看不到的，可以这么说，如果你走进我的公寓，如果我不指出天线的位置，你几乎是找不到的。
FROM MY FRONT DOOR:
从进门开始讲起：
那有七根天线，完全看不到吧！
So, will this fly for you? That’s between you and your XYL. Here’s a diagram of my apartment and the antennas which hopefully should make a lot more sense…
所以这些会在悬在你头顶？那是在你和你的 XYL之间。下面的图表是公寓和天线的示意图，这样你可以了解得更清晰。
The orange lines represent a 20m dipole with 2 ground radials rather than 1. The purple lines represent a 40m dipole. Dotted gray lines represent fishing line tied to the end of a wire to keep it stretched. Blue circles are plant hooks. Measurements are similar to regular dipoles (approx. quarter wavelength per leg), but I cut these long and used an antenna tuner to shorten them until I reached a 1:1 SWR. Once the SWR was set, I returned my borrowed antenna analyzer and the resulting antenna network seems pretty stable! I’m totally impressed with myself.
橙色线表示与20米偶极和2根接地线而不是1根。紫色的线代表40米偶极。灰色点线表示线终点并保持延伸。蓝色的圆圈是钩子。和常规偶极天线一样测量(约四分之一波长)，但是我把这些长线修剪了，并使用天线调谐器缩短他们，直到达到了1:1 的驻波比。驻波比调整完毕之后之后，我用借来的天线分析仪测试，天线信号收发似乎很稳定！我对自己的杰作感到震惊。
not too shabby ‘eh?
没有很松散吧？
The physical assembly involved a package of ceiling-mount (screw-type) plant hooks and a couple packages of 50′ of picture hanging wire from Target (a few bucks total). The coax to the radio is pretty straightforward. Just a short patch of cable running up to the ceiling, then the shield goes one direction (to the 3 ground wires) and the center wire goes in the other direction (to the antenna elements). Both antennas are permanently soldered together, which is fine because SWR stays low and I don’t have to jumper things around when I want to change bands.
实际装配包括天花板的旋转挂钩和几包50英尺的画用于挂线(总共就几块钱)。电缆和电台直接连接，一段电缆连接到天花板上，然后屏蔽线是三根地线一个方向，中间的地线直接连通到天线单元。天线都是永久地焊接在一起，这很好，因为这样驻波比可以保持比较低的状态，我不需要在改变波段时调整这些天线。
Here are some photos to show it more clearly…
下面是一些更详细的照片：
and, yes, that’s a sketch of a painting I haven’t painted yet
是的，一张草图，我还没上色。
DONT GET CONFUSED BY THOSE COILS! They’re not used for the antenna!!! They’re just there to help weigh down the wire to prevent it from wobbling due to the AC. Seriously, they do nothing, you don’t need them. They’re not even touching the antenna! Which reminds me, the two 20m radials were made from actual wire (because I had it lying around), so they’re coated in yellow. No biggie! No reason other than convenience that I didn’t use the picture hanging wire. Okay, that sums it up.
不要被这些线圈搞迷糊了。这些并不是用于天线。它们只是用于降低交流电造成的信号扰动。可以这么说，他们没起到什么作用，你根本就不需要它们。他们和天线八竿子打不到一起。这些提醒了我，这两根20米半径的线都是实际的电线，我把它们都漆上了黄色。不要紧！除了方便，我没有使用图片挂线。好了，这就是我的总结。
I hope this information helps! If you build a similar setup, let me know – I’d love to see it. If you have questions, feel free to email me. Remember, I didn’t put much math into this – I just went with approximately quarter wavelength legs and started cutting them until the SWR was down to 1:1, then I didn’t adjust it any more. It’s been several days and SWR seems stable, so no antenna analyzer is needed anymore. Good luck with your project, and with any luck I’ll work ya’ on the band. 73!
我希望这个信息可以帮助大家。如果你和我一样把天线这样架设了，请和我联系，我很愿意看到它。如果有任何问题，可以给我发电子邮件。记得哦，我没有在这里放太多的数学公式，我只是用接近接近四分之一波长的
阵子并修剪到驻波比至1:1，我并未调整其他东西。经过几天的测试，驻波看起来非常稳定，所以也不在需要天分仪了。祝你的天线工程好运并在每个波段都工作顺利。73！
–Scott, AJ4VD
http://www.swharden.com/blog/2010-02-07-simple-diy-stealth-apartment-antenna-for-20m-and-40m/
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