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Grounding and Starlink

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offgrid-curious

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Aug 29, 2023
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I've recently installed Starlink at my off-grid cottage, however the number of trees cause a large number of obstructions for the dish. I've seen some videos on Youtube of people mounting their dishes in trees and I think this is my best option. I've reached out to a local arborist who will take on the job. Because I'm in the process of completing my solar install, I've been thinking how I can mitigate any surge/grounding issues that this set up could cause.

I'm using a POE injector (https://www.amazon.com/dp/B0CQC4321X) to power the dish instead of the Starlink router, which includes 8KV of lightning protection. The POE injector has a ground connection which I've connected to my ground bus bar in my indoor panel. The dish is connected with a shielded CAT5e cable. I believe the injector will handle ESD protection just fine.

What I'm more concerned about is lightning/surge protection. The candidate tree I'm looking at is about 50ft high and the tree is about 80 feet or so from the cottage. My plan is to mount the dish on the end of a pole above the top of the tree. I'm worried that this essentially turns the tree into a lightning rod. I don't know if I could mitigate this by perhaps using PVC pipe instead of metal -- schedule 40 PVC pipe is weather resistant so I think would hold up.

20240504-09-00.06.png

Would it be a good idea to put something like a Midnite SPD-115 on the DC supply that is going to the POE injector? I see this as a good protection for any surge from making its way back into my system if there was a lightning strike closer to the dish. I'm also wondering if it would make sense to connect the POE injector directly to the outdoor ground bus bar, to avoid as many indoor components as possible.

Is this idea crazy? Am I just asking for trouble?
 
If you want to eliminate any possibility, you could set up a couple panels with DC charge controller near the satellite modem and use an ethernet-fiber media converter on both sides. The fiber will be non-conductive.

A reasonable enough path is to use Ethernet surge suppression on both sides with sufficient grounding rod. Consider running a larger gauge ground wire between the two sites as well.
 
IMO - put a ground rod next to the base of the tree and tie that to your pipe. It is not electrically part of the system so independant ground isn't going to apply.

Then on the tree down near the bottom install the appropriate one of these - I use the one that has 3 stages to it for the POE pass-through to my weather station. Tie this to the ground rod as well. Then put another one on the outside of the house doing the same thing but tied to your house grid.



These units are basically not connected to the wires of the ethernet but rather when lighting strikes it ionizes the gas in the tube and the TVS diode to provide a short to ground.
mapsofilti said:
If you want to eliminate any possibility, you could set up a couple panels with DC charge controller near the satellite modem and use an ethernet-fiber media converter on both sides. The fiber will be non-conductive.
Click to expand...


This is a good idea too
 
Just use a cheap battery backup with ethernet protection ports on the side inside the house with all other electronic gear.

I had an issue with a client that was hit by lightning on its coax line because they forgot to ground it. It went through the coax to the modem thru the firewall through the network switch thru cables and friend 3/4 of phones and computer network ports. We had a 2nd switch that went through the ups for protection and all those devices were perfectly fine.
 
One other idea occures - keep the starlink air gapped. Panels and batteries at the tree. Long range wifi pointed at the house, then setup a wifi router at the house to act as a bridge verse router

no wires, no connection and all is well even if you take a direct strike. I would still drive a rod at the tree to act as ground and use the L-com unit as a buffer between the antenna and the base station.

But in this case you might get away with using 50ft of pipe with the cables inside it. Stand it next to the tree and strap it to it. Clamp at the top with coronal points left on the mast top and cut a slot in the pipe above ground to bring the wires through.

Basically what I am doing with this. The point sticking up are a few strands of a #2 bare ground wire unwound. The rest goes into pipe clamps attached to the pole. In my case 1.5" radio shack antenna mast in 10ft sections. I used guy wires attached to springs to account for the sway of the top when the winds hit 80mph.

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Once you know the obstruction zone on the Starlink, why not just top the trees in the way? Less trees hanging over your cabin means less storm damage in high winds.
Mounting anything to a growing tree is asking for problems in the future. Short term solution at best.
If it’s a Gen three antenna, you have to initially aim it manually for the electronic antenna steering to work properly. No motors.
 
I don't see a good reason to be using shielded cable here. You're just introducing an unnecessary conductor. Unshielded works fine.

Best solution: standalone off grid power system for the dish at the base of the tree, fiber optic networking back to the house. If you were in a very lightning prone area.
 
Thanks for all the feedback folks, this is helpful.

robbob2112 said:
IMO - put a ground rod next to the base of the tree and tie that to your pipe. It is not electrically part of the system so independant ground isn't going to apply.
Click to expand...
Isn’t it though? Starlink is powered by POE coming from my battery, which is bonded to my house ground through the shielded ethernet cable. If the dish is also bonded to the pole, wouldn’t adding a ground rod at the tree create a ground loop?

I do like the idea of the 3 stage POE pass through - I could put one of those at the dish location and another just before entering the cottage that would be in front of the POE injector.

While I like the idea of an air gapped system, I don't really think it is feasible in my location. Too cold in the winter and not really any space to set up the panels/station.

Boomerweps said:
Once you know the obstruction zone on the Starlink, why not just top the trees in the way?
Click to expand...
There are just too many trees to cut down, and besides, the trees are what make the place so incredible. I'm trying to co-exist with them. Fortunately for me, I have a gen 2 antenna with the motors, so once the dish is up there it should be able to figure itself out.

It looks like my area has a relatively low density of lightning strikes (average of 1-2 per km²/year). I'm leaning towards just putting it up in the tree with some good POE surge protection in place and calling it a day.
 
offgrid-curious said:
Thanks for all the feedback folks, this is helpful.


Isn’t it though? Starlink is powered by POE coming from my battery, which is bonded to my house ground through the shielded ethernet cable. If the dish is also bonded to the pole, wouldn’t adding a ground rod at the tree create a ground loop?

I do like the idea of the 3 stage POE pass through - I could put one of those at the dish location and another just before entering the cottage that would be in front of the POE injector.

While I like the idea of an air gapped system, I don't really think it is feasible in my location. Too cold in the winter and not really any space to set up the panels/station.


There are just too many trees to cut down, and besides, the trees are what make the place so incredible. I'm trying to co-exist with them. Fortunately for me, I have a gen 2 antenna with the motors, so once the dish is up there it should be able to figure itself out.

It looks like my area has a relatively low density of lightning strikes (average of 1-2 per km²/year). I'm leaning towards just putting it up in the tree with some good POE surge protection in place and calling it a day.
Click to expand...


If you are going to run an ethernet cable to the tree then I would also run a EGC with it and bond that to the pipe. Having protection in multiple places along the cable is fine, but everything is going to be directed back to your house ground that way. Should still be fine and follow the rule about everything at the same potential and all using a single ground.
 
What about airgapping Ethernet with fiber, and then finding an isolation transformer to airgap the power. You don't need that much power passing capacity on the isolation transformer for a Starlink, so you can put the $$$ into kV of isolation rating and surge clamping on both sides.

Someone will need to convince me why the Starlink needs to be bonded, except maybe for RF signal integrity. I doubt safety. PoE and DC powered network electronics like access points and IP cameras are generally floating.
 
LOL - I had lightning ride an ethernet cable into the house once - blew up everything tied to the router and switch it was plugged into. Caused the japaneese caps on the motherboard of the server to pop their tops in some case or just plain explode.
 
Lightning is attracted to the highest point, and any metallic conductor from a pipe to Ethernet cable, is going to provide a path to ground.

In addition to the usual problems, you are going to have tree issues, leaves, needles, sap, bugs, etc.

If you are going to use the tree, I would also put a ground rod at the base of the tree with a Polyphaser PoE lightning suppressor, a conduit to the house so you can replace the cable when it gets hit, and another Polyphaser at the entrance to the house with another good ground.

I had a weather station get hit by lightning, and the Ethernet cable burned through to ground every couple of feet along its length. Blew the cover off a webcam, the anemometer came down in pieces, and the datalogger was just fine. That lightning went miles to get to you, a few inches of 'insulation' isn't going to make much difference.
 
My weather station from that strike went flying in many different pieces - in all directions Davis Weather Vantage Pro - the old style that was wired for the ethernet and the 24vdc poe to the under raincup heater.
 
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