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spammyduck
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PowerBox Long cable PoE in = all PoE out Short Circuit

Wed Apr 01, 2020 4:44 am

Tried with both a Powerbox and a RB260GSP using 24v provided PS with the Mikrotik PoE injector/splitter thing and also with a 30v PoE power supply . Units had v6.40.something and I couldn't even use a 13m cable without this problem. Upgraded the powerbox to 6.46.4 stable and it will work with the 13m cable but I need to use a 65m cable and the problem returns when I try it.

Trying to power any PoE device (tried a Ubiquiti radio, cambium ePMP, and powering the RB250GSP with the PowerBox just to test) with a PowerBox that is powered via PoE In with a short (couple of meters) Cat6 cable and it works as expected, will power any/all of the above devices. But when power the PowerBox (or RB260GSP) with a Cat6 cable longer than 30m or so the PoE out shows "Short Circuit" and it will not power the devices on "auto" nor Forced On.

It seems the solution to this problem was a enable a setting called PoE In Long Cable back in 2017 but that setting no longer exists , is there a solution or can you not use a long cable for PoE In if you plan to use PoE out ?
 
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macsrwe
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Re: PowerBox Long cable PoE in = all PoE out Short Circuit

Wed Apr 01, 2020 7:08 am

I believe you will find the answers to precisely these questions here.
 
spammyduck
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Re: PowerBox Long cable PoE in = all PoE out Short Circuit

Sun Apr 05, 2020 8:36 pm

That is from 2014 and the solution was enabling the setting - “ether1-poe-in-long-cable” as of around 2017 Mikrotik disabled that setting and you can no longer use it.

So, is it no longer possible to use PoE Out if you the PoE In cable is more than about 30ft long ?

Does the PowerBox " Pro " suffer from this same limitation ?
 
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macsrwe
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Re: PowerBox Long cable PoE in = all PoE out Short Circuit

Sun Apr 05, 2020 8:54 pm

No, they have not removed it -- it is just hidden well, as it always has been. See image, taken today on operating equipment. If you had followed the instructions in the 2014 document, you would have found it.

Note that this parameter is only available for old models of outdoor POE-out units that do passive POE only (not 802.11af).
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spammyduck
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Re: PowerBox Long cable PoE in = all PoE out Short Circuit

Mon Apr 06, 2020 4:11 pm

"If you had followed the instructions in the 2014 document, you would have found it."
"Note that this parameter is only available for old models"

In other words, it no longer works, as I stated... so on newer models there is no way to use a PowerBox to power anything if the PoE In cable is more than 10m long.

Seems that is an important limitation they should make people aware of...
 
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macsrwe
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Re: PowerBox Long cable PoE in = all PoE out Short Circuit

Thu Apr 09, 2020 10:43 am

There is no "in other words."

In this post, you say, "I bought a Mikrotik PowerBox (didn't realize at the time there was a Pro version)."

You have Powerbox, which is old model (although still sold) and uses only passive POE. ROS command shown is available on old model, and usually always needed.

Powerbox Pro is new model, uses 802.11af. ROS command provided is not available there, and not needed, because power supply is entirely different. But that doesn't apply to you because you don't own one!

Have you even tried using the command I provided images of?
 
spammyduck
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Re: PowerBox Long cable PoE in = all PoE out Short Circuit

Fri Apr 10, 2020 9:08 pm

Yes I tried using it it was the first thing I tried as the first solution I found when I started trying to figure this out. If you look at the settings in the PowerBox it shows ether1-poe-in-long-cable: no however when you do set ether1-poe-in-long-cale=yes it simply ignores it. There is no error but ether1-poe-in-long-cable remains "no" it simply ignores your attempts to change it. I tried down and upgrading to various firmware versions and it simply ignores the command to change it.
 
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macsrwe
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Re: PowerBox Long cable PoE in = all PoE out Short Circuit

Sat Apr 11, 2020 3:14 am

I think you ought to report this as a bug. As I showed in the image, it's still possible for ROS to report a yes setting that was set some time ago, but if it no longer allows you to set a yes setting, I really believe that is a bug. These devices need that setting to run in almost all situations, without it they are worthless.

I don't dare do this experiment on the only units I have remaining, as they are all running in production and would become useless without that setting.
 
dnordenberg
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Re: PowerBox Long cable PoE in = all PoE out Short Circuit

Sat Apr 11, 2020 9:30 pm

FWIW, I use about 35m cat6 to power a powerbox pro FW 6.45. I do not use a poe injector, instead I splitted out 4-5,7-8 from cable and attached them to a 2A 24V DC supply with battery backup. Load is two ubnt AF5XHD about 200mA each and two ubnt airMax devices about 130mA each if I don't remember wrong plus powerbox pro itself. Never seen this problem.
 
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macsrwe
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Re: PowerBox Long cable PoE in = all PoE out Short Circuit

Sat Apr 11, 2020 9:42 pm

Thanks, but powering a Powerbox Pro is irrelevant to this thread, as the subject problem is present only in older Powerbox (not-Pro) and original Omnitik models, which use passive POE only.

Our experience was that the issue showed itself over as short as an 8-meter cable, about the absolute minimum you could use to mast-mount an OmniTik over the top of a residence.

But your posting does suggest another possible solution -- running an additional two-conductor outdoor irrigation cable up to the unit with two barrel-connector ends, and powering the unit directly via its DC input, will evade this problem.

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