Earlier quoted context omitted.
>and based on the strength of that signal Wrong. Utterly wrong.
Would you explain why?
No. The Internet is at your fingertips.
GPS antenna mods make Starlink terminal immune to jammers
31–40 of 78 posts
Re: GPS antenna mods make Starlink terminal immune to jammers
#32Earlier quoted context omitted.
But how do these jammers work? They can't point at the sky to blind the satellite because there's no receiver; they broadcast from above ground, so in theory putting your receiver in a metal box with the top removed solves the problem?
Wait, starlink is one way? How does it know what to send?
you use your 14.4 dial-up modem for sends. Oh, sorry, thinking about HughesNet.
Re: GPS antenna mods make Starlink terminal immune to jammers
#33Re: GPS antenna mods make Starlink terminal immune to jammers
#34Question: Would using GPS antenna that only points at the sky (vs more omni-directional ones that mobile devices must have to work in any position) would "fix" the jamming problem ?
That's essentially what he's doing. The patch antenna he's using have a null at the horizon, where ground-based jammers would be.
OK, thanks. That info wasn't in TFA, nor in the article it linked to.
Re: GPS antenna mods make Starlink terminal immune to jammers
#35Earlier quoted context omitted.
>and based on the strength of that signal Wrong. Utterly wrong.
Would you explain why?
Here's a great explainer of GPS starting from really basic concepts.
Re: GPS antenna mods make Starlink terminal immune to jammers
#36Question: How come aircraft can so easily get jammed then? They use GPS for precise positioning in flight, so I'm guessing they have the very best antennas...
> They use GPS for precise positioning in flight
Large airliners, for the most part, don't. They use inertial navigation. GPS is a source of calibration for their inertial navigation system. There are some (non-precision) approaches that use GPS.
Re: GPS antenna mods make Starlink terminal immune to jammers
#37Does Starlink have a mode where you can manually tell it its lat/long? For a semi-stationary receiver, surely that would be a better way to bootstrap a connection.
I would assume that Starlink needs the GPS signal more for timing than for position though it certainly does need to know its position as well. Some of it is probably also driven by regulatory and UX requirements -- from a consumer standpoint there is a benefit of using GPS reception as a checkpoint before the process proceeds. Under normal operation if the terminal can't receive GPS then it is likely also unable to communicate with Starlink satellites.
One could use a GNSS emulator and this modification to test how the system performs under various GPS fault conditions to quantify it. My hunch is that it's more of a regulatory check than an operational requirement. I suspect the signals from the Starlink satellites themselves are sufficient for the terminal to derive timing and position without having to rely on GPS at all.
Re: GPS antenna mods make Starlink terminal immune to jammers
#38>> IMMUNE TO JAMMERS No. That is not a thing. At most, one can make equipment less susceptible to jamming. Jamming is not like hacking, it isn't a matter of whether an attack works or does not. It cannot be fixed via a patch. Pump out enough energy close enough to the target and even a hyper-directional antenna can be jammed. Have a look at military GPS jammers. They aren't the little dongles that you can buy online…
Right, look at the US' current jammer suite, the AN/ALQ-99, while it has issues it's unbelievably powerful. One of the downsides is that it jams the AESA radars of friendlies in the area, including the plane using the jammer itself. The next gen replacement sounds like an absolute monster too, but without some of the donwsides like the need for a ram air turbine to power it.
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Re: GPS antenna mods make Starlink terminal immune to jammers
#39Earlier quoted context omitted.
But how do these jammers work? They can't point at the sky to blind the satellite because there's no receiver; they broadcast from above ground, so in theory putting your receiver in a metal box with the top removed solves the problem?
>> putting your receiver in a metal box with the top removed solves the problem No. Radio can turn around corners. It can also bounce off things. Radio is light, but at a much longer wavelength. It is less like blocking a laser and more akin to blocking out sound waves. Blocking line-of-sight to the transmitter would block the laser but would do little to block sound waves.
GPS is on 1575.42 and 1227.60 Mhz, though.
Isn't that above the critical frequency you'd get ionosphere reflection at? (Which makes sense, since the signals are coming from outside it at LEO)
Re: GPS antenna mods make Starlink terminal immune to jammers
#40>> IMMUNE TO JAMMERS No. That is not a thing. At most, one can make equipment less susceptible to jamming. Jamming is not like hacking, it isn't a matter of whether an attack works or does not. It cannot be fixed via a patch. Pump out enough energy close enough to the target and even a hyper-directional antenna can be jammed. Have a look at military GPS jammers. They aren't the little dongles that you can buy online…
Atomic clock and hard coded GPS Location for the win?!
You joke, but have fun ensuring your clock is synced to everyone elses, even if it is incredibly accurate...