How vulnerable are our gateways really to be destroyed by e.g. nearby nodes?


#21

gp901.

and this is the same setup, only 2 meters higher and in a rural flat area.


(Nsornin) #22

your gateway can NOT be destroyed by a node or a GSM transmitting even very close to the antenna.
But static charge built-up can , so make sure you are using a DC grounded antenna.
You can check this very simply, using your Ohm-meter, you should see a short circuit between the ground and the RF pin your antenna cable connector.


(Arjan) #23

A note on lightning protection from Slack today:

@Caspar [12:50 PM]

uploaded this image:

@jmarcelino [1:22 PM]

what's that big metal thing on the n connector? surge protector?

@Caspar [1:31 PM]

Lightning Protection, missing the cable to earth atm... - http://varia-store.com/Accessories/Lightning-Protection/Lightning-protection-5-6GHz/Lightning-Protection-N-Plug-N-Socket-Bulkhead-5-6GHz::255.html

@jmarcelino [1:50 PM]

Thanks. Always bern suspicious of those gizmos, just doesn't seem possible they'd do much


(Remko) #24

Ligtning protection does not stop with an lightning protection at the antenna. Protection shall be insatlled to the (UTP) cables at the mast and before entering the building. Lightning protection shall be connected to a proper ground for the purpose of protecting the building from lightning. Wthout is is of no use.


#25

You are right @pe1mew, i am missing the connection to ground atm on the photo. To protect the ethernet wires i use those (before the cable enters my building): https://www.ubnt.com/accessories/ethernet-surge-protector/ and the mast was connected to ground (from my electrician) already.


(Remko) #26

Sounds perfect!


#27

Nearby lightning discharge and a LoRaWAN gateway. Ain’t the best combination :-1:

Because I wasn’t at home when a major thunderstorm hit the Netherlands on 9 august 2018 I couldn’t shutdown my Lorank8 gateway and disconnect the antenne before the storm hit Almelo (ok, shutdown was possible by SSH but disconnecting a antenna is a physical thing).

From my work I monitored my TTN Enviromental map for the storm to hit and saw the sudden rise in humidity and drop of the temperature when the storm hit my home as you can see in the image below (timestamps are in UTC). But also a major drop of 16dB on the RSSI (link).

Because of the large amount of rain in that store I hoped that the antenna or cable had some water damage and after some cleaning this problem would be fixed. But measering the antenna and cable which seemd ok, I changed the antenna and cable just to be sure. But no increase of RSSI was to be seen. So I feared that the RX part of my gateway would have been damages by a nearby lightning discharge.

Early Juli 2018 I was asked by Wietse (who lives in my area) for some support on his graduation assignment involving a LoRaWAN case. He also told me that he is very interested in weather monitoring and had a professional weather monitoring system incl a professional lightning detector who sends data to a central server. So when I told him about my findings he was willing to search data for a lightning map of 9 august 2018 and send me a animated GIF of that day. He also told me that a had some discharges to close for comfort near my home and so the location where the LoRank8 gateway is installed.

Confirming my fear that a nearby lightning discharge has probably damaged the RX part of my LoRank8 gateway. The only thing I could do now is to buy a new RF board for my Lorank8. A thing my wallet ain’t gona like. :frowning:

Also posted on my website : http://www.ph2lb.nl/blog/index.php?page=nearby-lightning


TTN Gateways lost range and RSSI after nearby lightning strike
(Arjan) #28

It seems persisting the RSSI is a great way to prove the damage to one’s insurance. (Though in The Netherlands not all will cover induction.)


#29

As was going to look in that, I believe that they cover it.
But there is a things “eigen risico” (Deductible).


#30

One of my new years resolutions was to replace the “deaf” concentrator board of my Lorank8 gateway. Today it got delivered and so it was time to install the new board (and a N-N female Coax lightning protector).

photo5891054255492673484

And the proof of the pudding is in the tasting, so waiting for a new sample to get in and take a look what the RSSI has done.

Screenshot%20from%202019-01-10%2022-15-47

And the RSSI had restored to it’s old level (after the nearby lightning strike it dropped 22 dB on my nearby nodes).

Screenshot%20from%202019-01-10%2022-15-40

So when everything is ok, the northern part of Almelo should have it old coverage again. :slight_smile:


#31

you have a link for that ? :sunglasses:


#32

That I do have for you : https://webshop.ideetron.nl/Webwinkel-Product-202254817/N-N-female-Coax-bliksembeveiliging.html
I still have to install in outside (you don’t want one installed inhouse) and hook it up to a separate earth pin (damn dutch rain). And I don’ t have the illusion that it will help with a direct hit, but luckily I have some large buildings around my house with professional lightning safety installation (those telecom guy know how to spend money). But I hope that It will suppress the static charges what you get from a nearby hit. Time will tell.


#33

tnx… I have to order one after your story :sunglasses:


(Jeff Uk) #34

Me too! (N-Type) plus anyone know of good source of SMA versions?! :wink:


#35

These kind of lightningprotectors will guard your house against a nearby/direct hit, but te RF-components would probably still get defect. Better is to use a multi stage surge protection device. But these things are more expensive than a concentrator board. lightning-surge-protector-n-male-to-female-bulkhead-50-ohm-0-3ghz-with-90v-gas-tube-coaxial-wifi-lig__41uvLH3QPmL
versus (Polyphaser DGXZ+06NFNF-A)

Polyphaser


(Amedee) #36

This one was also linked earlier in this post…
https://varia-store.com/de/produkt/31415-alfa-network-alr06-blitzschutz-n-buchse-auf-n-stecker.html