On Sun, Oct 16, 2022 at 1:31 PM Steve Stroh via Starlink <starlink@lists.bufferbloat.net> wrote:
On the battlefield, high power continuous jamming such as you describe tends not to last very long. There are special missiles (HARM - High speed AntiRadiation Missile) to remedy that situation. They home in on a jamming transmitter like a beacon.
this is called "ballistic anti-jam" :-)))) 

One of the stellar attributes about Starlink is that it’s using phased array antennas on both user terminals and satellites, proving a “tight beam”. I’m speculating, but my guess is that clever programming is configuring the satellite beams to be contoured to ignore contested areas where jamming is being attempted. An additional speculation is that Starlink is programming both the satellites and user terminals to continuously authenticate each other’s transmission, allowing them to ignore spoofing attempts.

Not to mention that the directional nature of the beams allows for a positional reality check. If a terminal is attempted to be used by the enemy and the terminal’s internal GPS is spoofed to say it’s well within Ukraine (good guy territory) rather than its real location outside Ukraine (bad guy territory), the satellite can discern that a terminal really isn’t where it’s reporting it is, and that terminal gets (permanently?) deauthorized.

On Fri, Oct 14, 2022 at 13:45 Mike Puchol via Starlink <starlink@lists.bufferbloat.net> wrote:
Pumping out RF at fairly high power levels, and pointing an antenna at a satellite, are both things very easy to do for someone like Russia. To then jam 500 MHz of spectrum all at once is not that trivial, and one can get creative, eg by only attacking the reference subcarriers in OFDM, thus concentrating RF power on those, rather than the whole channel. 

There are some papers written around jamming LTE by attacking specific resources instead of the whole band, making the attack less conspicuous, something similar could be applied against Starlink. By not using brute force, you also make the attack harder to detect and counter.

My view is that Russia is not worried about being noticed, and just applies brute force.

Best,

Mike
On Oct 14, 2022 at 20:26 +0200, Juliusz Chroboczek <jch@irif.fr>, wrote:
Juliusz, see the Twitter thread I linked to, it explains precisely the
jamming scenarios they could be facing, and how they are possible.

I saw it after I wrote my question, and it does explain a lot. Thanks.

Do you have an idea how difficult it is to actually do in practice? Is it
a simple matter of plugging a second-hand VSAT dish to an old amateur
radio rig, or do you actually need to be a research lab of the Moscow
Academy of Sciences to do it?

-- Juliusz
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