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Rocket M5 Rebooting Issue

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ng1p
ng1p's picture
Rocket M5 Rebooting Issue

I have a mesh node that has been on the air for just over 2 years. Its mounted at the top of a 250' tower and fed with 300 feet of shielded UV rated Ethernet cable, Starting about a month ago I noticed its performance bandwidth is way down and when worked hard it reboots. Doing a "WiFi Scan" it reboots all most every time. The signal levels from the surrounding mesh nodes all report the same as the day this node was installed and SNR is the same, I replaced the power injector with a new one and that made not change. I wish I could see what the voltage level is at the Rocket but I know that is not something the AREDN firmware supports. So I assume at this point its the Ethernet run or a bad Rocket? If its the Ethernet run I would have assumed that the signal levels would have changed but no change.

Any thoughts? I did look at the logs and don't see any things that is helpful (why the reboot?)

Thank you!

K6AH
K6AH's picture
I've seen resets like this

I've seen resets during what looks like normal operations and found it due to one of the power conductors not being sufficiently crimped.  The power conductors are as follows:

4 & 5 = V+
7 & 8 = V-


Andre, K6AH
 

K6CCC
K6CCC's picture
Power.

I would agree with Andre - a power problem.  What voltage are you feeding to the bottom of the cable for this node (measured, not guessed)?  300 feet of Cat-5 is within spec, but barely - especially for PoE.
 

ng1p
ng1p's picture
Power

Measured at the power injector I see 24.8v. What's the best way to measure the voltage under load. Just testing at home with a 300 foot Ethernet cable and with the same power supply I'm seeing 24.5v at the end of that long run. 

So if it's a bad crimp I can just recrimp perhaps. I guess when the weather gets better I will get a new rocket, crimper, and another run of Ethernet and see what one fix's the problem. I wish we had a way to remotely measure the voltage. Reading the specs a Rocket can run fine even at 15v. A bad crimp (poor connection) seems very possible. Still I would think the signal level would drop but maybe not.

thank you

nc8q
nc8q's picture
What's the best way to measure the voltage under load.

Use a 1/2 length cable under load.
Lift a wire from pin 4 or 5 and a wire from pin 7 or 8 at the POE injector end.
Measure the voltage, under load, on those wires.
That reading is your voltage at the load.

Use an equal length of cable under load.
Lift a wire from pin 4 or 5 and a wire from pin 7 or 8 at the POE injector end.
Measure the voltage, under load, on those wires.
Voltage drop will be double that of regular cable.

At the device end of the cable:
https://www.amazon.com/Triplett-POE1000IL-Brothers-Analyzer-Voltmeter/dp...

I hope this helps,
Chuck
 

AB7PA
Possible issue with UBNT remote reset circuitry?

If you're going to get a replacement unit for your tower, you might consider a Mikrotik BaseBox instead of a UBNT Rocket.  It would be a drop-in replacement which does not have the known UBNT issue with auto-resetting (mentioned on AREDN forum threads like this one).  There are some UBNT forum posts about this (example here).  Not sure if this is part of your issue, but might be worth considering.

ng1p
ng1p's picture
BaseBox

Does the BaseBox slide into the same mount on a Ubiquiti 13dBi Omni mount that a Rocket uses? That would be interesting if it does plus I'd see another 3db TX power.

kl7ut
kl7ut's picture
Power

Check to ensure that the Cat 5/6 cable is actually copper... I've run into this problem in commercial installs. The CU plated AL works ok on short runs or long non POE runs, but fails on a longer POE run due to the higher resistance.

Good Luck!

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