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Comment by GJim | Hacker News Reader

> The cruise companies hate it and prohibit it

The prohibition on all and sundry on using their own radio trancevers (yes, that includes satellite transceivers) is to prevent the risk of causing RF/electrical interference with the ships systems. The use of low power Wi-Fi and cellular phones is fine, but poorly set up directional VSAT terminals can play havoc with ships navigation and comms kit. This is historically the reason for banning their use without explicit permission in writing from the ships master.

Source: Marine engineer.

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I'm an electrical engineer - I don't understand how what you said can be true at a wide and effective scale. Of course any device can interfere with something else - But what kind of evidence exists that starlink terminals, and in particular the pattern steering and bands use, actually cause interference in a meaningful way to activly used marine system used on these kinds of crafts.

Starlink used Ku and Ka bands, so we are talking about 10-12Ghz and 37-42Ghz downlinks, and 14Ghz and 47-51Ghz uplink. This is highly directional radiation, and even with beam forming and reflections is not likely to have any specific high interference risk. Clearly the downlink transmission from the satellite is exceptionally low power at the ground, even with the beamforming used in the satellites.

I would love to learn that this is a real problem with actual tested data.

> This is highly directional radiation

That's the entire point!

A poorly set up antenna can cause havoc. This is historically the reason for denying passengers use of radio transceivers. Maybe Starlink is harmless, I don't know. But if it is, it will still take time for international maritime safety legislation to catch up.

Source: Marine enginner

I fully understand the risk of highly directional radiation - but that is why I was asking if there was some actual specific testing done. I believe the software in the Starlink (and the beamforming) is designed to only transmit when it knows where it is pointing ( it uses receiver information and ephemeris data to know where and how to transmit ).

I would suspect that if the dish was instead pointing directly at someone with no direct satellite reception there would not be high transmit power.

Again, of course it could be catastrophic in unheard of ways, but is there any evidence of that as a real outcome, potential and likely outcome, or even likely theoretical outcome?

I can understand it takes time for legislation to catch up, although that is far more a 'choice' than a requirement.

Ah yes, the old "interference on the tenth harmonic" explanation.

Really? Which bands are in use that are interfering? Why are the downlinks not wreaking havoc today?

> Why are the downlinks not wreaking havoc today

The entire point is the concentration of RF energy per unit space.

Downlink from a satellite in LEO, this is fuck all.

The uplink, in front of a directional VSAT antenna, this is very significant.

The fact you do not understand the difference suggests you are commenting outside the area of your expertise.

"The uplink, in front of a directional VSAT antenna, this is very significant."

This is reasonable, and I fully can understand that direct transmission at reasonable power going into a sensitive receiver can be problematic. In practice I suspect it would require some particularly aggressive intent to aim it such that you see that condition - and of course at the point you are at intent the 'rules' are optional.

Never ceases to amaze me that glibertarians think they can do their thing on board a ship more than on land.

They can if it's their ship.

The ship has to fly a flag, and be captained by a master mariner licensed for that tonnage, by the country flying the flag.

> glibertarians think they can do their thing on board a ship more than on land

Who are the glibertarians?

I assume you mean rich passengers (and libertarian seasteaders!) rather than the ships master concerned about the vessels safety.

Exactly. The people who think they can bring their ideology to a platform where you have to obey the captain.

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