A lot depends on SW as well. Best way to pass is to put it in a box, but thee are some other things you can try that involve $$.
You can contact me directly and we can have a lively discussion about your issues. Gerald On Tue, Mar 3, 2015 at 1:24 PM, Jonathan Mash <[email protected]> wrote: > Good Afternoon, > > First off, thanks to the BB community for making this such a great > resource for those working on the BBB and other boards. I have personally > spent hours on this forum. > > I am hoping that someone monitoring this group may be able to help me and > my company solve an EMC problem that we are facing the the BBB. *We are > open to paid consultations to aid in solving this issue (Gerald?)*. We > are building a product around the BBB that needs to pass FCC part 15 Class > B. We are having trouble passing the tests mostly around the 625 MHz range. > We were only 1-2dB above the limit in one lab and almost 10dB over at > another lab (yes, test equipment makes a big difference!). We tried it with > and without our custom shield attached. > > There is another thread here: > https://groups.google.com/forum/#!searchin/beagleboard/625/beagleboard/Y6BhtzKx2oY/YQ_xjmmkWusJ > that seems to have the same problem. That thread seems to have lost > attention of the key players in this group so I thought I would create > another thread to bring more attention to this critical issue. > > We have done some pretty aggressive modifications to the board and the > only way we can get the board to pass is by completely disabling (and > depowering) the LAN PHY. This was accomplished by removing FB4 and mangling > part of the device tree so we don't get a kernel panic on startup. Not an > elegant solution, I know. > > As suggested in the other similar thread, we tried shorting R136 but it > actually made the noise worse. > > We also tried disabling (removing Y4) the McASP oscillator as that was > also generating quite a bit of noise. Didn't help enough. > > Has anyone other than CircuitCo been able to successfully pass FCC with > the BBBw/Ethernet enabled as part of a system? CircuitCo was probably able > to pass because they could isolate the BBB with big filters on all cables > because they aren't selling the BBB as as system but as a component. > Because ours is a "Commercial System", we need to test with all cables as > they would be typically installed. No giant chokes for us. > > Thoughts? Comments? Suggestions? > > Thanks! > > Jon > > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- Gerald [email protected] http://beagleboard.org/ http://circuitco.com/support/ -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
