Page 1 of 1

Losing Ports to 11x

Posted: Tue Jun 18, 2019 10:46 am
by mhoppes
I have one site where every rain storm it seems I lose an 11x port on the switch. The port will just blow, keep providing power, but no Ethernet and the Ethernet link is down. Swap ports/switch and everything is good until it rains.

I moved the 11x over to an external power supply, and then cabled it into the switch -- and it's been great for weeks.

Any ideas what might be going on here? There are tons of other radios on this tower and have been for years without any issues.

I'm using 26-400-AC switches.

Re: Losing Ports to 11x

Posted: Tue Jun 18, 2019 1:05 pm
by sirhc
So possible issue and grasping at straws here Matt: Ground current

When it rains the service ground rods are getting reduced in capacity and this 11x radio is shortest cable on tower and the ground current is interfering with communications.

The POE adapter is isolated and preventing this current to flow on this line?

As I stated a long time ago here on this forum there are 2 options with the switches to deal with poor grounding.

1) Isolation - what we tried initially

2) Bonding AC ground to DC ground like UBNT does with their radios which causes this issue. You can verify this by using a meter to test impedance between PINs 7,8 to SMA connector which will show direct pass through.

We first tried isolation then went to bonding and recently we started taking another stab at isolation but better isolation with our AC switches by removing some filter CAPs on the power supply DC output side which seems to help until the AC current reaches 400-500 Hz which can definitely happen from the normal 50-60 Hz when there is a bad electrical motor or such on site or the ground current from the service provider from near neighbor or near ground strikes.

If it is ground current you could try adding additional ground rods to the service and making sure the tower rods are bonded to the service rods with #2.