打算DIY一个20米端馈天线，打算拿漆包线来做振子。大概也就 10-20w 发射。计划是用无人机绑着鱼线飞过去对面楼顶一个废弃的晾衣杆绕一圈再飞回来，然后绑着漆包线慢慢拉出去。为了防止有碍观瞻，所以线越细越好，目前手头上有一捆 0.5mm 直径的漆包线，不知道会不会太细。

交流电欧姆定律和直流电差不太多，就是[imath:0]U=IZ[/imath:0]，阻抗在天分的史密斯图上就能看到，加上功率，这俩反推可得电流。集肤深度[imath:0]\delta=\sqrt{\frac{\rho}{\pi f\mu}}[/imath:0]，[imath:0]\rho[/imath:0]为电阻率、[imath:0]f[/imath:0]是频率、[imath:0]\mu[/imath:0]是磁导率，可以问商家得到。有了集肤深度就可以得到截面积，现在有了截面积、电流、然后商家肯定也能提供线缆在不同横截面积下的最大电流，适当大一些就行，毕竟大部分能量都会辐射出去，剩下的才会发热。 @"BA7KSH"#p43057 万一是喜欢放风筝的大爷呢。

天线上的功率是以电磁波的形式辐射出去高频信号有集肤效应所以粗细对功率的消耗并没那么明显线的粗细主要影响带宽 , 有看到说用0.12mm的镀银线 600w测试都没问题. 唯一麻烦的在于线细了容易拉长变形和断裂实际上消耗功率的大头在巴伦上所以都是考虑巴伦的耐受值天线振子可以忽略不计

@"BI7KGD"#p42896 感谢友台，拉长和断裂的问题有考虑过。线材只能裁剪到 20M 的样子，然后剩下的交给天调，断裂的问题因为用了鱼线，增加了韧性，应该也还好。先架设解决有无的问题，后续升级可能会考虑用特氟龙镀银线。

我先不说别的。。你这带宽基本就没了

要注意下占空比，玩SSB和玩数据的耐功率是不同的。

我用过0.5mm包塑钢丝，10多米，阳台拉到楼下树上，天调调谐，使用和带宽没问题，通联也还OK，不过我一般不用大功率，怕影响邻居;漆包线肯定也OK，只是相比钢丝容易断，尤其是刮风拉回晃动的时候，连接处有断的风险，安全措施要做好。

@"BG2EFX"#p42929 有天调还管他个锤子带宽🤭

@"BG2EFX"#p42929 大概差不多就行了，剩下的就交给天调。谁不想搞个750正V，无奈在市中心中间楼层，实在是无奈。

@"BI1JNP"#p42953 好的好的，估计拉好天线也就玩玩FT8，白天上班忙，晚上传播又不行。只能挂挂FT8了

@"BI1AVH"#p43001 钢丝貌似也不错，我最近看了下特氟龙镀银线和漆包线。漆包线是最细的，就一根线拉直了几乎不可见，缺点上面的友台也说了，就是时间长了会拉长导致谐振点变化。还有一个问题就是你说的，刮风来回晃动担心存在金属疲劳断掉的风险。砸楼下倒是不太担心，因为巴伦一头计划使用伞绳绑着的，就算漆包线断掉也没啥大问题

漆包线估计不抗拉，还是得注意

How to calculate antenna power tolerance?

BG4TRF

Since balen is fire-resistant, are you worried about the wires being damaged by heat?

BI7LVX

BG4TRF Because the antenna broke, I had to reattach it, which was quite a hassle.

BI4MIG

BI7LVX With so many people flying drones now, I'm wondering if the automatic obstacle avoidance system can actually detect them.

BG2EWI

BI4MIG It's very difficult; even with thicker wires, you often experience short circuits. And this fine wire makes it even more challenging.

BG2EFX

BI7LVX I used it for several years.
And isn't the best arrangement of Teflon-coated silver also structured like this?
Don't overthink it; try it and see. Don't just focus on theory.

BI7LVX

BG2EFX While the Teflon's tensile strength is definitely stronger than that of coated wire, I found that even using 0.2mm transparent Teflon wire, the concealment effect wasn't as good as that of coated wire. It really comes down to personal preference. As always, if conditions allow, who wouldn't want to install a large Yagi antenna on the roof?

dxs660

The biggest problem with coated wire is that it can stretch and deform over time, causing the original impedance matching to deviate from the center frequency and become non-impedance matched. You can search for this on Bilibili; there are examples of this, using keywords like "impedance matching antenna".

bg2kud

BI7LVX I can use either a 20-meter slant pole or a 16-meter 1:9 ratio.

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