> {quote：title = paulh写道：} {quote}>有趣的天线戴夫。
是的，这是一个有趣的天线。
我曾经为一家制造类似天线的公司工作。
这是一个非常好的公司，因为所有规格都是发明的！
发明了增益和辐射模式。
测量了SWR，但是如果它超出规格，它通常会被出售。
他们销售的设计中有各种电感器，没有关于如何计算值的文档。
这一切都被切断了，我想，并且由于没有人关心性能，如果90％的功率喷射到天空或变成热量并不重要！
在那里工作的时候，我接受了HFSS的试验，并试图了解基本的同轴共线天线。
有很多关于它们的文章，但找到很多有用的信息似乎很难。
如果增益为9 dBi或9 dBd，我设置链接的设计甚至没有说明，但它实际上约为7 dBi，并且假定无损耗的电介质和导体。
>另外还有另一种测量同轴电缆或双绞线等阻抗的方法，如果您可以使用示波器和函数发生器，那么“长长度或线轴”就很简单了。这次没有VNA
周围:) >>你做的是沿着电缆拍摄频率为几Mhz的方波。
使用BNC T连接器将电缆连接到一侧，将信号发生器连接到另一侧，并将其连接到示波器。
将电缆留在远端。
>>>调整示波器的时基，直到您可以看到方波中的振铃和步进。
由于反射波回到发电机，它看起来不像是一个干净的方波。
>>现在在电缆的远端连接一个可变的锅并调整锅，直到你的方波看起来干净。
>>>断开锅并测量其阻力。
测量结果将是电缆的阻抗或非常接近它。
>>谢谢保罗。
我懂了。
我想当线路的阻抗终止时，没有反射，因此没有方波的扭曲。
好主意。
您应该写一篇论文“100种方法来测量同轴电缆的阻抗”。
戴夫
以上来自于谷歌翻译
以下为原文
> {quote:title=paulh wrote:}{quote}
> Interesting Antenna Dave.
Yes, it is an interesting antenna. I used to work for a company that made antennas similar to them. It was a pretty alful company to work for, as all specifications were invented! Gain and radiation pattern were both invented. SWR was measured, but if it was out of spec, it was usually sold anyway. The design they sold had various inductors in them, with no documentation about how to calculate the values. It was all cut and try I think, and since nobody cared about the performance, it did not matter if 90% of the power was squirted into the sky or turned into heat!
Whilst working there, I got a trial of HFSS and set about trying to understand the basic coaxial colinear antenna. There is a lot written about them, but finding much useful information appeared to be hard. The author of that design I put a link to does not even state if the gain is 9 dBi or 9 dBd, but it is in fact about 7 dBi and that assumes lossless dielectrics and conductors.
> There is another method of measuring the impedance of the coax cable or twisted pair etc that comes to mind, "Long lengths or spool" that's fairly simple to do if you have access to a scope and a function generator., No VNA this time around :)
>
> What you do is Shoot a Square wave of a few Mhz in frequency down the cable. Using a BNC T connector connect the cable to one side and your signal generator to the other and hook it into a scope. Leave the cable open at the far end.
>
> Adjust the time base on the scope until you can see the ringing and steps in the square wave. It wont look like a clean square wave on the scope because of the reflected waves coming back to the generator.
>
> Now on the far end of the cable hook up a variable pot and adjust the pot until your square wave looks clean.
>
> Disconnect the pot and measure its resistance. That measured result will be the impedance of the cable or pretty close to it.
>
> Thanks Paul.
I see. I guess when the line is terminated in its impedance there is no reflection, so no distorsion of the square wave. Nice idea. You should write a paper "100 ways to measure the impedance of a coaxial cable".
Dave
> {quote：title = paulh写道：} {quote}>有趣的天线戴夫。
是的，这是一个有趣的天线。
我曾经为一家制造类似天线的公司工作。
这是一个非常好的公司，因为所有规格都是发明的！
发明了增益和辐射模式。
测量了SWR，但是如果它超出规格，它通常会被出售。
他们销售的设计中有各种电感器，没有关于如何计算值的文档。
这一切都被切断了，我想，并且由于没有人关心性能，如果90％的功率喷射到天空或变成热量并不重要！
在那里工作的时候，我接受了HFSS的试验，并试图了解基本的同轴共线天线。
有很多关于它们的文章，但找到很多有用的信息似乎很难。
如果增益为9 dBi或9 dBd，我设置链接的设计甚至没有说明，但它实际上约为7 dBi，并且假定无损耗的电介质和导体。
>另外还有另一种测量同轴电缆或双绞线等阻抗的方法，如果您可以使用示波器和函数发生器，那么“长长度或线轴”就很简单了。这次没有VNA
周围:) >>你做的是沿着电缆拍摄频率为几Mhz的方波。
使用BNC T连接器将电缆连接到一侧，将信号发生器连接到另一侧，并将其连接到示波器。
将电缆留在远端。
>>>调整示波器的时基，直到您可以看到方波中的振铃和步进。
由于反射波回到发电机，它看起来不像是一个干净的方波。
>>现在在电缆的远端连接一个可变的锅并调整锅，直到你的方波看起来干净。
>>>断开锅并测量其阻力。
测量结果将是电缆的阻抗或非常接近它。
>>谢谢保罗。
我懂了。
我想当线路的阻抗终止时，没有反射，因此没有方波的扭曲。
好主意。
您应该写一篇论文“100种方法来测量同轴电缆的阻抗”。
戴夫
以上来自于谷歌翻译
以下为原文
> {quote:title=paulh wrote:}{quote}
> Interesting Antenna Dave.
Yes, it is an interesting antenna. I used to work for a company that made antennas similar to them. It was a pretty alful company to work for, as all specifications were invented! Gain and radiation pattern were both invented. SWR was measured, but if it was out of spec, it was usually sold anyway. The design they sold had various inductors in them, with no documentation about how to calculate the values. It was all cut and try I think, and since nobody cared about the performance, it did not matter if 90% of the power was squirted into the sky or turned into heat!
Whilst working there, I got a trial of HFSS and set about trying to understand the basic coaxial colinear antenna. There is a lot written about them, but finding much useful information appeared to be hard. The author of that design I put a link to does not even state if the gain is 9 dBi or 9 dBd, but it is in fact about 7 dBi and that assumes lossless dielectrics and conductors.
> There is another method of measuring the impedance of the coax cable or twisted pair etc that comes to mind, "Long lengths or spool" that's fairly simple to do if you have access to a scope and a function generator., No VNA this time around :)
>
> What you do is Shoot a Square wave of a few Mhz in frequency down the cable. Using a BNC T connector connect the cable to one side and your signal generator to the other and hook it into a scope. Leave the cable open at the far end.
>
> Adjust the time base on the scope until you can see the ringing and steps in the square wave. It wont look like a clean square wave on the scope because of the reflected waves coming back to the generator.
>
> Now on the far end of the cable hook up a variable pot and adjust the pot until your square wave looks clean.
>
> Disconnect the pot and measure its resistance. That measured result will be the impedance of the cable or pretty close to it.
>
> Thanks Paul.
I see. I guess when the line is terminated in its impedance there is no reflection, so no distorsion of the square wave. Nice idea. You should write a paper "100 ways to measure the impedance of a coaxial cable".
Dave
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