Seeking Your Interest In RoadTesting Ethernet or SMA Eval Kits

I've had that same experience.. trying a high-value attenuation and getting nowhere near it! 

I was wondering how to seal each stage, in the easiest-to-assemble way I could think of. I sketched the following, it still needs work, and might not be the best way.

If (say) it was a 4-stage (where each stage shouldn't be more than about 25 dB) then that's 100dB of attenuation if desired.

The idea being that each section could be boxed with a screening can. The resistors (or at least some of them) would be large (e.g. 1210 sized) SMD, so that they could dissipate some power.

Once the cans are soldered (with a high-power iron), the adjacent cans joining each stage would need to be bridged with solder too, to prevent RF finding a way to the outside world between the stages.

The cans are cheap in quantities of 10. Slightly taller versions would be better, but this is all I could find and might be OK:

The SMA connectors could be soldered on the other side, and then solder used to fillet all the way around the edges of each connector. Also every via hole could be soldered over if required!

Don't know if it's worth building though, because it would be hard work to solder the cans without a high-power iron. Also it would only work up to a few hundred MHz.

Regarding a coupling loop near an attenuator (if it isn't fully shielded), or close to coax braid, it would work, but would be hard to know what the attenuation would be (and it might vary over frequency). But might be good enough! 

I have interest, but not the equipment to do an adequate test.

This is a very interesting device and I never knew this existed (up to 5Gbps!). The reason I find it interesting is because I see it as the easiest way to implement an optical slip-ring. At work, we use some very complicated  (and expensive) optical slip rings to pass fiber links across rotating things. Something like this could simplify that task by at least two orders of magnitude. The SMA version of the kit is more interesting because The TX/RX can be directly connected to any FPGA Eval kit with transceivers to test. Those typically come with SMA TX/RX ports too so it should be fairly straight forward to test. BERT tests can also be done this way.

The thing I don't like too much is that there isn't much information about the device itself (detailed datasheet?) on the Broadcom website, and also pricing is not available anywhere. For example, I wanted to understand if multiple of these can be used in the vicinity, and how accurate the optical alignment needs to be, etc. This information would dictate what specific use cases it could be used in, for example building slip rings with multiple fibers, etc.

You ask some detailed, specific questions that I'm not sure the datasheet alone would answer them. I can ask Broadcom.

Randall

The slip ring application is very interesting.

Although you could have multiple fiber links in fairly close proximity, you could only have one fiber in a slip ring application because a slip ring must rotate around a single free-space optical link. You could, of course, use OFDM to send multiple channels though a single link. I'm a little bit tempted to try this technology in a slip ring application.

or maybe CWDM? CWDM technology have gotten way cheaper recently...

Thanks for the comments.