6 ms·

Unless SpaceX has implemented high speed frequency hopping (which would 10x the cost of end user devices), they can easily be jammed. It isn't hard to overpower

by dsl 7y ago

Unless SpaceX has implemented high speed frequency hopping (which would 10x the cost of end user devices), they can easily be jammed. It isn't hard to overpower a single from space with a ground based transmitter.

ecpottinger 7y ago
It is also easy to control the direction your receiver see it's signals from, to properly jam a satellite you need to fly the jamming equipment high in the air on a plane/balloon. A ground based jamming will have to be very powerful or close to block a receiver that is pointed to the sky.
- baq 7y ago
  how about overpowering jamming signal aimed at the sat? genuine question, no idea about the physics here
  - rini17 7y ago
    Probably feasible, but would create international tensions, in worst case retaliation - many countries jamming foreign satellites or taking other hostile actions. Yuck.
    - baq 7y ago
      aye. still better than shooting the bird down.
avar 7y ago
Even if you implement frequency hopping it'll do nothing for China blocking it. The end users need to hop to the same frequencies to receive the signal, which means that a jammer can do the same. This sort of thing works for militaries (e.g. for GPS) because you can assume that the receivers are secure, i.e. they're guarded by people carrying guns. That's not really a viable plan when a hostile state can just buy a receiver with the built-in hopping algorithm from a retailer.
- dsl 7y ago
  It works for (the US) military because they assign unique NET codes to groups and unique keys to transceivers. The frequency schedule is seeded using part of the key, the NET, and the day. The system is actually designed with the assumption that transceivers will fall in to enemy hands. Starlink could implement something similar where the schedule is seeded using a key stored on the device, the day, and the receivers serial number (or other unique value). Supporting a million receivers is the same as supporting one, it is basically just one more input to a hash function.

by dsl 7y ago

ecpottinger 7y ago

It is also easy to control the direction your receiver see it's signals from, to properly jam a satellite you need to fly the jamming equipment high in the air on a plane/balloon. A ground based jamming will have to be very powerful or close to block a receiver that is pointed to the sky.

baq 7y ago
how about overpowering jamming signal aimed at the sat? genuine question, no idea about the physics here
- rini17 7y ago
  Probably feasible, but would create international tensions, in worst case retaliation - many countries jamming foreign satellites or taking other hostile actions. Yuck.
  - baq 7y ago
    aye. still better than shooting the bird down.

avar 7y ago

Even if you implement frequency hopping it'll do nothing for China blocking it. The end users need to hop to the same frequencies to receive the signal, which means that a jammer can do the same. This sort of thing works for militaries (e.g. for GPS) because you can assume that the receivers are secure, i.e. they're guarded by people carrying guns. That's not really a viable plan when a hostile state can just buy a receiver with the built-in hopping algorithm from a retailer.

dsl 7y ago
It works for (the US) military because they assign unique NET codes to groups and unique keys to transceivers. The frequency schedule is seeded using part of the key, the NET, and the day. The system is actually designed with the assumption that transceivers will fall in to enemy hands. Starlink could implement something similar where the schedule is seeded using a key stored on the device, the day, and the receivers serial number (or other unique value). Supporting a million receivers is the same as supporting one, it is basically just one more input to a hash function.