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Puzzling Node Behavior

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w8erd
Puzzling Node Behavior
We have a rocket M2 on top of a tower. It stopped working recently.  By substitution on the ground we determined that both the POE and the surge protector were
defective, so we replaced them.  The Ethernet cable from the POE to the PC at the bottom had a broken clip, so we replaced that cable also. Now the node works fine to the outside world, but we cannot log into it from the ground.  The trouble shooting took some time and at one point we were able to log into the node from the ground.  Any suggestions?

Bob W8ERD
 
KG6JEI
Sounds like this could be
Sounds like this could be "lightning" damage.

Its common (in the WISP world) to hear that the Ethernet port goes offline even though the RF still works as its the most vulnerable due to the long run of cable being an antenna for stray (atmospheric inductive) currents.

Couple this with the fact the surge protector and injector are seen as "Defective" and this would be my best guess.
 
wb6tae
or... a defective crimp
or... a defective crimp connection on the new re-45 connector. happens all the time.
K5DLQ
K5DLQ's picture
Did you try setting your pc's
Did you try setting your pc's network adapter to 10Mbs and half-duplex?  (Last resort)
w8erd
Puzzling Node Behavior seems to be water
We have now found that water is coming out of the ethernet cable and causing corrosion and problems at the surge protestor and POE.
The cable is cat5e outdoor underground rated shielded cable.  Apparently water gets into the space between the outer jacket and the shield, probably thru inadvertent nicks somewhere along the cable, and runs down inside the cable to the equipment below.  So normal drip loops do not help.
The solution seems to be to open the outer jacket at the drip loop to allow the water to run out before it gets to the equipment.  And perhaps again right at the equipment.  We have this problem in several places and have now heard from others that have this problem.  This is the first winter exposure for the cable.
Have others had similar problems?

Bob W8ERD


 
K5DLQ
K5DLQ's picture
This is one reason why you

This is one reason why you would use a "flooded" cat5 cable, or, ultra-weatherproof like "Ubiquiti ToughCable Carrier".

k1ky
k1ky's picture
TC Carrier isn't "flooded"
Last time I looked, UBNT TC Carrier cable isn't "flooded".  It has dividers that can atually channel water between the pairs.  Thar's air in there!  No "goo" that I can remember unless they have changed something?
 
k1ky
k1ky's picture
Water in cable
Yes, that is a common problem and you are on the right track for a solution.  We have varying types of cable on our towers and the "cheaper" stuff is most susceptible.  It gets damaged mostly by the tower climbing activity with climbing belts chafing the cable, causing water entry points.  It gets worse when water is in the cable and it freezes, causing more problems and ruptures in the jacket.

Drip loops, surge protectors (water stops as I call them) and opening the cable before the equipment are all good ideas.  We also use little cable tie "flags" at the node connections, building entry points and the like to give water an alternate path to follow.

We do these same procedures for our coaxial RF lines as well.

If water gets into the connector, it starts to conduct and it simulates a node reset, then progresses to total failure - no power to the node, bad data connections and the like if gone unchecked.
 

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