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Belyivulk
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Ethernet fail after lightning? A possible fix...

Mon Jul 21, 2008 10:03 am

Hi Guys,

Recently weve had terrible trouble with some RB133C ethernet dieing after lightening storm. It always happens to the same customers, and everything is grounded properly / cabled correctly. The radio is untouched and the POE continues to deliver power, but it wont transmit data and if you look in winbox (over wireless) you can see the ethernet going "no link" / "link ok" over and over.

So we locked the ethernet on the router to "10mbit", and turned off "autonegotiation" and BAM! Ethernet works ok again. We're not sure whats happening but this appears to make the ethernet usable again.

In one instance we have replaced the router 4 times, replaced the cable / POE / AC Adapater, running on a surge protector with ethernet filter and it still happened. So, i hope this helps someone out there!
 
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ghmorris
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Re: Ethernet fail after lightning? A possible fix...

Tue Jul 22, 2008 3:00 am

Same problems here. Typically a damaged system will work for a while on 10Mbit, but its a clear warning the board is on the way out.

I wish MT would spend the extra money (and charge me for it) to put industrial grade Ethernet ports on all RBs, or at least build some models in the range with a 'hardened' feature set.

We have Trango 900 radios in the exact same environments that have NEVER blown an Ethernet port, ever! Yes, they cost silly amounts of money compared to a RouterBOARD, but a few bucks extra would be worth it to save the truck rolls and annoyed customers.

George
 
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Belyivulk
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Re: Ethernet fail after lightning? A possible fix...

Tue Jul 22, 2008 3:02 am

Agreed! Many of our customers are 100km + (return trip) from our base of operations, so the travel cost wipes our our profits, much less the cost of a new RouterBoard
 
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Re: Ethernet fail after lightning? A possible fix...

Tue Jul 22, 2008 10:41 am

Yes. Many dead Ethernetports here too. The 18/24V PSUs are dying easily.
Some Customers have report all other devices on the same powerstrip are still
alive after a storm but MT-PSU died. So it's lower quality than usual.

We've problems with the Ethernetplug of 411 boards, too. Some cables do not
fit exactly enough. So some customers get bad ethernetconnections after a
while. We're mounting the 411 with Ethernet to the top. But even there are
problems.

We've gotten a dead RB1000, ...

So MT has to do some work on Quality assurance.

We hold a stock of Equipment just for the next lightning.

Stefan
 
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Belyivulk
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Re: Ethernet fail after lightning? A possible fix...

Tue Jul 22, 2008 11:16 am

It is a shame to see so many failures, especially since MT is a VERY robust / affordable platform. I guess its hard to give high quality / robust equipment very cheaply, and with Ubiquities 'nano station' that puts the pressure on even more. Having said that, i cant forsee us moving away from MT equipment anytime soon!
 
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Re: Ethernet fail after lightning? A possible fix...

Tue Jul 22, 2008 2:06 pm

MT is certainly very affordable, not so sure about the 'very robust'. We are spending at least $20k dollars per month fixing broken stuff on towers, and another $10k fixing broken stuff at customer sites. That does NOT include the cost of the hardware , that is ONLY the labour component. I am more than fed up with it!!

As a result, our interest is rapidly moving in the direction of hardware that doesn't break as easily. We have 'stuff' on 100M towers and are getting fed up with having to replace bits and pieces constantly. The weather has been horrible this year with double the number of normal lightning strikes, but that really isn't the point, because for five years now we have Trango 900 APs on the same towers, grounded the same and cabled the same that we have never had to touch. We have 300 Trango SUs at customers and I think we have had to change out five in five years. Not a bad average...

RB problems are blown or degraded Ethernet ports typically, with a few blown radio cards (ususally R52s, the XR2s and XR5s are more durable). The new series boards are much better than the 230s but still nowhere near good enough.

Power injectors and power supplies come from Pac Wireless so MT is blameless there. We have good luck with POE 24i's as they seem to sacrifice themselves to protect the RouterBOARDs.

I would cheerfully spend a little more money on industrial quality hardware. For every extra dollar we spent in hardware cost we would save at least ten dollars in labour and travel expense. Like you, we typically have a 100km + round trip to fix something. Some days we put on 500km just running around fixing lightning damage to MT gear on towers. This is bizarre and has to change!

George
 
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Re: Ethernet fail after lightning? A possible fix...

Mon Aug 04, 2008 8:52 am

Started putting these in the RB enclosures and so far I haven't lost an ethernet yet.

http://www.titanwirelessonline.com/Prod ... PE-IISG-48

Started doing these about 6 months ago, so it is still early.

Eric
 
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Re: Ethernet fail after lightning? A possible fix...

Mon Aug 25, 2008 12:55 am

Hi Eric,

How do you ground these? I am quite keen to solve this problem as its happening a lot to us at the moment
 
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Re: Ethernet fail after lightning? A possible fix...

Mon Aug 25, 2008 6:44 am

About a month or so ago we had a lightning storm come thru and damaged a RB333. Every thing was grounded except the cat 5 cable running to the radio. It is a shielded cable direct buried about 200 ft. Well the RB kept running but was deaf on the POE ethernet port. What was bad was that the RB was up for just over a month. I wasnt in the mood to replace it since it was working on the RF side so I split the cat5 cable and put a new RJ45 connector just for the blue and brown pairs. That went to the POE ethernet port for the power. I put a second RJ45 connector for the orange and green pairs and ran it to the second ethernet port on the board. That was our quick fix and It works just fine. I hope that the board continues to function for sometime as I want to get my moneys worth out of the board. Hope that this may help others that have this kind of problem

Mike
 
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Re: Ethernet fail after lightning? A possible fix...

Mon Aug 25, 2008 6:57 am

Hi Montana,

unfortunatly that wont work for us as we seem to only have trouble with RB133 with only one ethernet port. But it may help others!
 
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Re: Ethernet fail after lightning? A possible fix...

Tue Aug 26, 2008 4:33 pm

About a month or so ago we had a lightning storm come thru and damaged a RB333. Every thing was grounded except the cat 5 cable running to the radio. It is a shielded cable direct buried about 200 ft. Well the RB kept running but was deaf on the POE ethernet port. What was bad was that the RB was up for just over a month. I wasnt in the mood to replace it since it was working on the RF side so I split the cat5 cable and put a new RJ45 connector just for the blue and brown pairs. That went to the POE ethernet port for the power. I put a second RJ45 connector for the orange and green pairs and ran it to the second ethernet port on the board. That was our quick fix and It works just fine. I hope that the board continues to function for sometime as I want to get my moneys worth out of the board. Hope that this may help others that have this kind of problem

Mike
I have done that too, but this will not work on a 133c. Only 1 ethernet port.
Network Consultant in Wichita, KS
 
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Re: Ethernet fail after lightning? A possible fix...

Tue Aug 26, 2008 4:46 pm

Hi Eric,

How do you ground these? I am quite keen to solve this problem as its happening a lot to us at the moment
Best Grounding:
Run a #10 copper wire up the pole to the building penetration point. The wire should be at least 4 inches from shielded network cable. The top of the ground cable should go no higher than the grounded device. There should be a surge suppressor at the protected device and a lightning arrestor at the bottom near the service entrance. The shielded cable should be grounded at the top and service entrance as well.

Using this technique I have a rooftop with 2 wrap boards that have been running without reboots for 3 years and a 333 for 6 months 155 ft up on a high rise rooftop about 1 block from a copper roof building that gets struck in EVERY storm. I am using the building ground bus instead of my own rod which I think introduces some wireless noise but is a lot simpler than repelling 150 feet with a hammer drill to attach a ground cable.
Network Consultant in Wichita, KS
 
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Re: Ethernet fail after lightning? A possible fix...

Tue Sep 02, 2008 2:03 am

Typically, I will mount that type of arrestor in the enclosure. Just make sure the enclosure has enough room. Then I ground the enclosure (metal) to some #10 copper or something similar. If it is a good grounded tower, then I ground it to the tower. If not (such as a water tank), I run it down the side to about 2-3 interconnected ground rods. Also, make sure you use shielded cat5.

Eric
 
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Re: Ethernet fail after lightning? A possible fix...

Thu Sep 11, 2008 5:56 pm

Interesting reading. Here maybe a sollution but not for all.. In my environment I cannot tolerate any noise from those dreadful smps units hammering away at 20-40 khz spreading harmonics all over the HF spectrum via ethernet cables that run vertically up a tower.

Also am reluctant to run 220 volt up a tower.

But try using centre tapped isolation transformer running with output at 50-0-50. Getting a shock between 50v and 0 aint so bad as 240.

Then use a power supply at the top that is not SMPS. A standard regulated supply or even crudely regulated at around 18 volt might do. Make sure that it is for 110 volt primary.

Then like as you do in this country, the overhead lines get struck nearby and the Line goes wildly high, sometimes 2 or 3 times 220volt.

At least the supply will then either double to 36V or worse case 54volts. I am sure that the primary secondary isolation within the transformer would be tolerant.

In this scenario, the routerboard is not stressed.

Then back at the power supply, use MOV transient supressors across the supply rails that will clamp at double the volts.

Use antisurge fuses before hand to tolerate the momentary clamp.

In my case I do not intend to use the POE via LAN, infact I intend to "lift" the LAN or isolate it by using 8 pin DIL relays. This way the LAN also wont radiate noise back down the tower:

The PSU at mast end, energises the relays too and lifts the LAN. But just incase the power supply fails, the relay then closes and the LAN becomes active. The Routerboard can then be reactivated by POE over LAN1.

Of course in my situation, the RB433 with 5.8g card and 2.4g card are just used as a repeater site, with no customer using the hard wire LAN:

Regarding lightening, try using the methods used by commercial broadcast engineers. Never have an antenna like the type we use immediately on top. If it is possible to use panels just below tip of mast, so much the better.

Use conductive guys above the antennas to dissipate the charges through the guys to a ground mat. Never allow the ethernet cables to come into contact with the mast. Run ethernet on its own up the centre of a tower and isolated from the legs. Same applies to coaxials.

There is stacks ofstuff around on that ttopic.
 
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Re: Ethernet fail after lightning? A possible fix...

Thu Sep 11, 2008 10:05 pm

regarding your problem with cabling/harmonics. If you use shielded cable, you'll likely be OK. I know what you mean; I have lots of utp cat5 in my house, and as I add devices, I get more and more noisy frequencies in my VHF radios while scanning.

At my towersite, every cat5 is shielded, and we have a tenant that succesfully receives AIS VHF traffic that is -120dbm. So apparently our shielding works good here. Other tower sites the tenant has used are too noisy for the AIS gear.

If you wanted to run AC up the tower you could run it through a 1:1 transformer and it would be isolated. No shock hazard from touching one conductor then.

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