[AFMUG] Ethernet Interference from Grounding using GIGE-APC

[Nate Burke]

I just changed out an ATOM mikrotik to a CCR, and found that it is 
Incrementing FCS Errors exactly every 30 seconds on the Ethernet line 
from a Trango LYNX.  The lynx is powered via DC, so the Data line is 
clean of POE.  I am using a GIGE-APC Unit on the Ethernet line.

What I found through testing, was that the FCS Errors only happened when 
the GIGE-APC was plugged into the chassis.  They happened at exact 30 
second intervals.  Because of this I'm guessing that there is something 
introduced via the ground that is causing them.  If I pull the GIGE-APC 
out of the Chassis, the errors stopped, if I plugged it back in, the 
errors came back, at the exact same clock points (in my CCR Log, always 
at 06 and 36 seconds regardless of the timing of plugging/unplugging).  
I'm using the 1U APC chassis, and there are other GIGE-APC, 444APC-HV, 
and GIGE-POE-APC units in it. None of the other equipment is plugged 
into the CCR, so unsure if it would increment FCS Errors on those.  They 
are all plugged into RB1100's, and have no errors logged in the mikrotik.

Any place to start troubleshooting something like this?  Would it make 
sense that something on the ground plane could cause these Ethernet errors?

I believe that this is causing some very low level packetloss through 
the link, about 1 packet every 5 minutes or so, I'm guessing based on if 
the ping falls directly on the error frame.

Nate