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@darconeous
Last active November 21, 2023 23:51
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Hacking the Rectangular Starlink Dishy Cable
@sjkjs
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sjkjs commented Aug 12, 2023

It's well documented in the Tycon specification; the PoE does a pass through on the shield. You need to use a PSU which is floating but general purpose PSUs should do that; the only one I've found that did actually ground the output was a LinkSys PSU designed for a particular piece of equipment. Test it first.

The shield is meant to be grounded isn't it? I will be connecting the dish (via the PoE injector) to a network switch which is powered off a DC barrel jack and has a floating ground. So, if I used the Tycon injector and used its shield pass through, the shield would still be ungrounded at all 4 plugs (2 on the dish side, 2 on the switch side).

In this situation don't I need to explicitly provide it with a ground, or accept the risk of being ungrounded?

@jbowler
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jbowler commented Aug 12, 2023

In this situation don't I need to explicitly provide it with a ground, or accept the risk of being ungrounded?

Yes, the shield should be grounded somewhere. You have to make an explicit decision where to ground it unless the PoE injector does it. (The PoE injector for my other PoE aerial, from my original ISP, does ground the shield.) Normally nothing else in the cable run (including surge suppressors) will ground the shield.

In my StarLink arrangement I had the dish plugged in to a surge suppressor then from there to the Tycon WT then all the way to my router; this was in a box outside the house. I ran the drain wire out of one of the RJ45 plugs and just connected that to the same ground as the surge suppressor.

In the arrangement with my prior ISP I put a surge suppressor on the outside of the house, in a box, and had waterproof RJ45 sockets on that. IRC I had a shield pass-through to the PoE but I could have grounded the shield of the incoming RJ45 inside the box and arranged not to connect it on the outgoing connection to the PoE, or broken the connection to the PoE by using an unshielded cable in the last step (wall jack inside the house to PoE.)

NetGear PoE switches do ground the shield; for the ones with the wall-wart and the low voltage DC supplies there is a grounding screw on the case, for ones with built in AC power the shield is connected to the AC ground.

The rule, if there is one, seems to be to ground at the power supply; the PoE injector. All the switches I have provide shielded RJ45 sockets and all those shields are connected together. On one (a new TrendNET 10G switch) the shield is also connected to the power supply socket (12V 1A barrel connector). On another NetGear switch (non-PoE) the shield is isolated from the barrel connector. Since you are using a a switch I would expect every shielded cable plugged into it to be connected together so if any get grounded they all will be.

@sjkjs
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sjkjs commented Aug 13, 2023

I ran the drain wire out of one of the RJ45 plugs and just connected that to the same ground as the surge suppressor.

Thanks for the explanation. That all makes sense.

I'm using a Netgear GC110P PoE switch which doesn't have the shield grounded and also doesn't provide a grounding screw. The shield seems to be disconnected from everything.

I like your idea of using one of the spare RJ45 ports and running a drain wire to somewhere else that does have a ground. I might look at doing that too.

@darconeous
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For what it's worth, I grounded my 200' setup at two places:

  1. Using a Cat-6 surge protector close to the antenna, ~120ft away from the house. This grounds the shielding and provides an arc path to ground for the twisted pairs.
  2. Grounding the shielding at the service entrance for the house, no surge.

The ground at the antenna is it's own ground spike. The ground at the house is the shared house ground (luckily I could run a wire to that on the exterior of the house). Unclear if I'm going to ultimately have galvanic problems. Hopefully not. Resistance between the two independent ground spikes is fairly low.

Originally both ground points were going to be full CAT-6 surge protectors, but I was having trouble with them increasing the resistance slightly so at some point I decided to just ground the shielding at the service entrance. That was before I switched to 52V, so perhaps I should revisit that... I'm hesitant to cut the wire though, since I can't un-cut it if it doesn't work out.

@jbowler
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jbowler commented Oct 6, 2023

Resistance between the two independent ground spikes is fairly low.

I'm very interested in knowing what that resistance is :-)

@darconeous
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I'm very interested in knowing what that resistance is :-)

If I remember correctly, it was a few ohms. I don't remember what it was exactly, I just remember thinking "wow, that's lower than I expected". I have an outlet nearby with a ground that is connected to the house ground (not the ground that the antenna is connected to) so one day I got curious and pulled out the multimeter. But a low resistance makes sense, we have a lot of minerals in our clay-type soil that also has considerable moisture content. And I really buried that rod quite well.

I'm curious now, we just had a lot of rain. I can check again tomorrow.

@crdiaz324
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Is it possible to use 2 of these making 2 custom Y cable to use only the 2 powered pairs of each injector?

Yes but you have to know exactly what you are doing and it's pointless since the Tycon, as documented above, works just fine so long as correct wire pairs are swapped. If you don't want to do that the one I posted links to on Amazon doesn't require the wire swap. Seriously though, the cable has to be cut with any of these solutions (except the two most recently posted) so attach the RJ45 modular plus and it really is no more difficult to crimp those on with the correct wire swap than it is to crimp them on without a wire swap. (Both are error prone of course.)

A single APOE03G costs the same as a single Tycon PoE (USD15 from Amazon, USD10+postage direct from Tycon).

I've successfully used the techcharmer.com kit with my modified dishy without having to cut or swap any wires. The process involved connecting the provided cable from the kit to the plug in the back of the dishy, and subsequently to the POE's power output. Then I connected the POE to my router utilizing a standard ethernet cable I acquired from Amazon. This setup has proven to be incredibly reliable, running seamlessly for approximately 4 to 5 months. The kit was roughly $30. Hard to beat that IMO.

@JustOneGuyHere
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JustOneGuyHere commented Oct 20, 2023 via email

@jbowler
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jbowler commented Oct 20, 2023

@JustOneGuyHere; @crdiaz324 was commenting on his previous post from July:

https://gist.github.com/darconeous/8c7899c4d2f849b881d6c43be55066ee?permalink_comment_id=4645398#gistcomment-4645398

It's worth noting that TechCharmer now sell that Tycon lookalike PSU with what appears to be YAOSHENG adapter I posted a link to (two posts down from the above). Here: https://techcharmer.com/collections/our-products/products/starlink-dc-adapter-kit The Amazon link I posted no longer works but it's here:

https://www.amazon.com/YAOSHENG-Rectangular-Adapter-Connect-Injector/dp/B0BYJTHX4P

It's a nice move by TechCharmer; they've undercut the YAOSHENG very expensive PSU ($81) with an adequate and well proven power supply (assuming it is one of the Tycons), but they certainly seem to be selling the YAOSHENG adapter as part of it. Everyone benefits. The only downside to the TechCharmer solution is that there is no surge protection that I can see, but there is none on the official StarLink router (aka incredibly expensive PSU) so far as I know.

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