darconeous/rect-starlink-cable-hack.md

## rect-starlink-cable-hack.md

      
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              rect-starlink-cable-hack.md
            
          
    Hacking the Rectangular Starlink Dishy Cable


These are are some notes I put together on butchering the rectangular dishy
cable.
FOLLOW THESE GUIDELINES AT YOUR OWN RISK. I TAKE NO RESPONSIBILITY
FOR ANY DAMAGE OR INJURY YOU SUSTAIN FROM FOLLOWING OR NOT FOLLOWING
THESE GUIDELINES.
Disclaimer: Don't do this

In general, if you can get away with using the original 75' cable (or
the official 150' long replacement cable), then that is ultimately
preferable to doing any of this stuff. If you don't already know why
you would want to do this then you definitely shouldn't do it. If you
run into trouble, the first thing Starlink Support is going to ask is
if the cable between your dishy and router has any modifications, and
for good reason.
Power

Despite the connectors being proprietary, the underlying technology
connecting the router and the rectangular dishy is gigabit ethernet
with non-standard PoE(The orange and green pairs are positive, the
blue and brown pairs are negative). The cable itself is plain stranded
STP CAT5e, suitable for outdoor use. The router acts as a 48V, 2A PoE
power supply, so 96 watts are available at the port the router.
Stick with the original router (and possibly the ethernet port dongle)
unless you have a good reason to try something else.
You cannot power dishy with a standard PoE injector, but if you are
enterprising enough you can rearrange the wires (swap blue/green, terminate as Type-B)
going into and out-of a passive 4-pair PoE Injector
and get it working with a sufficiently large 48V
or 52V DC power
supply.
Note that most 48V 2A power supplies on Amazon are insufficient!
I recommend this 52V power supply,
as I have confirmed that it works and I am using it on my own 200+ft run.
Resistance

Resistance is the primary limiting factor you will run into. As you
increase the length of the cable and add additional
terminations/connectors, resistance increases. If the resistance is
too high, the voltage at the dishy will (perhaps only occasionally)
drop too low, causing it to spuriously reboot or not boot at all.
The exact maximum round-trip power resistance that the cable can have before Dishy's stability
suffers isn't immediately clear, but 1.8Ω round-trip (~88 watts available
for Dishy) appears to be stable while 2.5Ω round-trip is just barely unstable.
(neither value includes the resistance of about 20 extra feet of the original
CAT5e that is used in my setup)
If you cannot easily measure resistance, you will need to be as
conservative as possible:

Keep the length of your entire run as short as possible and your
connectors as few as possible. Continuous runs are almost always
preferable to runs with connectors.
Use outdoor-rated cable for outdoor runs. If riser cable is all you have, paint it.
Don't directly bury the cable unless it is rated for direct burial. Otherwise, water intrusion will
eventually make your connection unreliable. The original cable is NOT rated for direct burial.
Use 23AWG (or larger) CAT6/CAT6A cable, which will contribute around 0.03Ω/meter
for a continuous run.
The original cable was only 24AWG,
so if you are using 23AWG cable then the less length you use from the original cable the better.
It would appear that connectors will each contribute ~0.02-0.1Ω to the round-trip resistance,
but more research is required.
Avoid unnecessary use of patch panels, they introduce additional
connectors and add resistance.
150' is likely the most distance you are going to get without
changing your approach (like splitting out the power into larger
guage wires, etc), but if you use a specialty low-resistance cable (like
this) then you might be able to
almost double that with some careful terminations.
Once you get everything set up, try turning on snow pre-heat mode:

If you can run a few speed tests in a row without problems,
then you are likely golden.
If your dishy reboots (either immediately or after running a
few speed tests), your cable resistance is too high.


For longer runs you may need to use a power supply with a larger
voltage. I can confirm that the rectangular dishy works fine on 52V.
Grounding

With a longer run, proper grounding and surge protection becomes more
important. Dishy must be grounded in some way. With the unmodified
original cable, that grounding comes from the router. Since we are
cutting that wire, we need to make sure that we provide that
grounding.

At least the the first RJ45 termination on the dishy side should
be a grounded RJ45 plug.
Use a high-quality, grounded, PoE-compatable ethernet surge
protector at the termination closest to your dishy.

If you do this at your "service entrance" (where the wire
enters your house), then you won't need a shielded ethernet
cable after that point---but you might want it to be shielded
to reduce RF interference.
If you do use a shielded cable after the grounded surge protector,
make sure you don't have a continuous ground between your surge
protector and your Starlink router---that would create a
ground loop, and you don't want that. If there is a ground
fault, some of the surge current could go through your
shielding!


Alternatively, you could forgo the surge protector and use shielded
cables, connectors, and plugs for the entire run and ensure continuity
between the starlink router and dishy (presumably the router has some
amount of built-in surge protection).