re: Seeking to Determine Who Will Enroll in SMA or Gigabit Ethernet Evaluation Kits

The evaluation kit for AFBR-FSEK50B00E piqued my interest after viewing this drawing.

My first thought was doing throughput performance comparisons.

I would use a two Pi as a test host and compare wifi, wired and optical link performance.

I'm curious that the development kit TX to RX sensors are fixed. What happens if the sensor separation varies.

Yes, I had the same reaction to the Ethernet based evaluation kit, but I don't think I would be able to do much more than just "performance testing" and "what if I move it slightly offside or further apart". I initially had the idea to use it on a rotating platform or through a window glass, but in the end, I'm not sure this is worth the sponsor's money.

Hello!

Is there a decision which one is going to be roadtested (Ethernet or SMA)?

I think it is an interesting subject - the copper Gigabit Ethernet seems easier to test, but the results could be somewhat limited by copper PHY media converters. I have (long time ago) done a project about the possibility of use Gigabit Ethernet in High Performance Cluster interconnects in place of Infiniband (which provided significantly lower propagation times - there was no RDMA over Ethernet possibilities then - but was very expensive).  

During my work I have started to wonder if copper Gigabit Ethernet physical interface introduces some additional delay - these times I was unable to find any solid information about this, but today it is clearly present in the Ethernet switch documentation (this one from one model of Netgear - different models may have different values, maybe it is also dependent on the chipset used):

Latency (64-byte packets)
1G Copper < 3.5us
1G Fiber < 2.5us

which difference may (or may not) introduce some artificial limit for the evalkit

I think that SMA version can be tested (at hobbyist level of lab) using some sort of passive DAC (TWINAX) cable breakout (copper cable connecting two SFP sockets - commonly used for optical interfaces, thus probably directly connecting TX and RX pairs) and two Gigabit Ethernet switches - but the signalling level should be verified. At first glance it seems compatible, but only after about of hour of research.

On the other hand, evalkit complete with Gigabit Ethernet media converters can be tested as optically isolated Gigabit Ethernet link - something very desirable to all kinds of Extreme Environment type scenarios (if power consumption is reasonable and it can work through the typical transparent lid [or dirty transparent lid] - but this remains to be tested)

Very interesting kit for roadtesting!
We use media converters quite extensively in the industrial network. I happened to have a Realktek rtl8201fc based media converter with me.

Hi, I was one of the commenters on the original discussion. My primary interest is in testing the kit to build an optical slip ring, since doing the same with fibers and traditional optics is quite difficult. Of the two kits, the one with the Ethernet media converter will be the easier one since the performance can be tested using ethernet devices. The other one (with SMA connectors) can be tested using FPGA kits with transceivers (the AMD kits have some utilities to test just the transceivers, and the broadcom kit can be the link joining the two transceivers together while doing the BER tests). Between the two I think the kit with ethernet will be definitely easier to test. Looking forward to the roadtest.

Best Regards,

Saad

I would be very interested to see how well the slip ring concept works.