Posted Fri, 30 Sep 2022 19:47:50 GMT by User, Forum

Hi, I have a question regarding the RSA 507A's USB connection as it relates to an upcoming RF sensor deployment I am working on. We are in the sensor design phase currently, and still deciding on which spectrum analyzer to use. Our setup will consist of an antenna, a custom built preselector, a spectrum analyzer, and a computer. The antenna and preselector will be deployed outdoors in a potentially high-off-the-ground location. We will either need to build a weatherproof enclosure to hold the spectrum analyzer in the same location, or we can run a cable down the antenna mast to an enclosure on the ground containing the computer. Due to RF cable losses, it would be ideal to place the RSA 507A near the antenna, and to run the USB connection to the computer a long distance, rather than to run a very long RF cable and a short USB connection. In trying to decide our course of action here, my question for you is: what are the limitations with the Tektronix RSA 507A's USB connection length? Aside from the provided cable, would there be any issues using a USB cable on the order of 50-100ft in length, assuming such a cable would probably have an active repeater (such as this one: https://www.amazon.com/Tripp-Lite-SuperSpeed-Extension-U330-05M/dp/B008VOPDOU). My worry is that it may be difficult to source high quality USB cables of this length, and that this may lead to problems with data transfer rates. Have you had any experience with similar deployments? What were the solutions in those cases, if so? For reference, we are considering other spectrum analyzers which use Ethernet instead of USB connections, which should not have a problem running such large distances. Is the only safe solution to bundle the RSA 507A + computer in a weatherproof enclosure nearby to the preselector?

Thank you in advance for any help that you can provide on this topic.

Posted Fri, 30 Sep 2022 19:52:51 GMT by Expert, Tektronix Applications

Hello,

In my experience, the USB connection should be kept short on the USB RSAs. This is mostly because the RSAs transfer quite a lot of data at the full 40MHz span (about 230MB/s streaming). The best option here would be to keep the RSA and the computer close together. A repeater would have to be used for certain, but I do not know of anyone who's tried such a setup. I've run short (~6ft.) USB extensions on our RSA before and had good luck, but more than that may introduce some connection reliability concerns at such a high data rate. Most systems similar to yours use a small computer in close proximity to the RSA, and then run the computer's ethernet connection and power down to the ground/base station.

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