HP/Agilent 8712 ET是否可以测试50欧姆负载

> {quote：title = wils写道：} {quote}> N9912A不支持波导套件或波导卡。
> Wil Wil，当你说“不支持波导套件或波导芯片”时，你的意思是说N9912A中没有代码来执行波导校准，或者安捷伦不会向试图使用波导校准的任何人提供技术支持吗？
当然可以在其中一个菜单中将校准从“同轴”改变为“波导”，如果选择波导，则输入波导的截止频率。
我的N9912A有问题，因此我将它退还给卖家，因此对我没有任何影响。
但我无法理解安捷伦为何不能轻易添加对波导校准的支持。
在我看来，至少有一些代码存在，因为可以设置波导并设置截止频率。
鉴于它在其他FieldFox仪器中得到支持，为什么不在N9912A中呢？
我得到的印象是N9912A中的软件功能有限，使其不太有用 - 可能是为了保护其他仪器的销售。
N9912A没有波导校准或者在QuickCal中具有不同连接器类型（N和APC7）的型号这一事实给我的印象。
这在QuickCal上似乎特别糟糕，因为它是用户必须付费的选项。
戴夫



     以下为原文

  > {quote:title=wils wrote:}{quote}
> N9912A does not support waveguide kits or waveguide cals.
>  Wil

Wil, 

when you say "does not support waveguide kits or waveguide cals", do you mean there is no code present in the N9912A to perform waveguide calibration, or Agilent will not offer technical support to anyone trying to use waveguide calibration? 

One can certainly change the calibration from "coax" to "waveguide" in one of the menus, and if selecting waveguide, enter the cutoff frequency of the waveguide. 

My N9912A is faulty, and therefore I am returning it to the seller, so it does not make any difference to me. But I can't understand why Agilent can't add support for waveguide calibration easily. It seems to me that at least some of the code is present, since one can set waveguide and set the cutoff frequency. Given it it is supported in other FieldFox instruments, why not in the N9912A? 

I get the impression the software in the N9912A is purposely limited in functionality, to make it less useful - perhaps to protect sales of other instruments. The fact the N9912A does not have waveguide calibration or have models for different connector types (N and APC7) in QuickCal, gives me that impression. That seems particularly bad on QuickCal, since it is an option users must pay for. 

Dave

> {quote：title = Yagi写道：} {quote}>您好，我收到了一份过时的HP / Agilent 8712 ET，75欧姆版本。
幸运的你。
我希望有人会给我一个VNA，虽然75欧姆版本当然不太可能比50欧姆版本。
>我想知道是否可以测试50欧姆负载（天线），可能使用阻抗匹配垫（虽然有损）或匹配的变压器，如HP 11694A或一些新的替代品。
>谢谢！
是。
请访问http://www.home.agilent.com/agilent/editorial.jspx?cc=US&lc=eng&ckey=1000002208:epsg:faq&nid=-536902444.0.00&id=1000002208:epsg:faq其中
讨论了在50欧姆仪器上测量75欧姆器件的相反问题。
但当然结果是一样的。
最小损耗焊盘的损耗约为5.6 dB，因此会使您的方向性降低约11.2 dB。
但对于测量天线，这不会产生任何实际差异。
将系统阻抗设置为50欧姆，并确保将校准套件的参数上传到仪器，因为固件中的所有参数都不合适。
观察您使用的任何适配器上的连接器类型。
在许多情况下，将一个50欧姆的男性安装到75欧姆的女性身上会损坏女性。
有一些75欧姆连接器的设计没有遇到这个问题，但它们是少数。
如果您要测试天线用于业余用途，使用过的85032B N型校准套件可能是一个不错的选择。
但请注意，eBay上的大多数都是错误的，不完整的或与它们有错误的部分。
母开口（85032-60002）是一个两部分结构，但在eBay上90％有外导体而不是小中心导体延长器。
顺便说一句，请考虑将您的用户名更改为YagiUda或类似名称，以反映Uda在该天线上完成大部分工作的事实 - 可能比Yagi更多。
如果您不了解Uda在天线开发中的作用，您应该研究它的历史。
Dave，G8WRBEdited：drkirkby于2014年5月7日下午1:57



     以下为原文

  > {quote:title=Yagi wrote:}{quote}
> Hello, I received as a donation an obsolete HP/Agilent 8712 ET, 75 Ohm version.

Lucky you. I wish someone would give me a VNA, although a 75 Ohm version is of course generally less desirable than a 50 Ohm one. 

> I would like to know if it is possible to test 50 Ohm loads (antennas) with it, maybe using an impedance matching pad (although lossy) or a matching transformer like the HP 11694A or some newer alternatives.
> Thanks!

Yes. See

http://www.home.agilent.com/agilent/editorial.jspx?cc=US&lc=eng&ckey=1000002208:epsg:faq&nid=-536902444.0.00&id=1000002208:epsg:faq

which discusses the opposite problem, of measuring 75 Ohm devices on a 50 Ohm instrument. But of course the results are the same. A minimum loss pad would have a loss of about 5.6 dB, so it would degrade your directivity by about 11.2 dB. But for measuring antennas, that is not going to make any practical difference. Set the system impedance to 50 Ohms, and make sure you upload the parameters of your calibration kit to the instrument, as all those in the firmware are going to be unsuitable. 

Watch the connector types on any adapters  you use. In many cases, mounting a 50 Ohm male into a 75 Ohm female will damage the female. There are some designs of 75 Ohm connectors that don't suffer that problem, but they are in a minority. 

If you are going to test antennas for amateur use, a used 85032B type-N calibration kit would probably be a good choice. But be aware that most on eBay are faulty, incomplete or have the wrong parts with them. The female open (85032-60002) is a two-part construction, but 90% of them on eBay have the outer conductor and not the little centre conductor extender. 

BTW, please consider changing your user name to YagiUda or similar, to reflect the fact that Uda done much of the work on that antenna - probably more than Yagi. If you don't know the role of Uda in the development of the antenna, you should research the history of it. 

Dave, G8WRB

Edited by: drkirkby on May 7, 2014 1:57 PM