[Starlink] Re: Starlink and Iran

[Ulrich Speidel <u.speidel@auckland.ac.nz>]

On 16/01/2026 6:42 am, Colin_Higbie via Starlink wrote:
> Can't the traditional approach of just flooding the air with noise reduce the SNR to the point that most packets are indecipherable? I don't believe this requires a digital or technically advanced approach nor a focus on GPS or anything else so specific, just sufficient power and ability to broadcast fully across the same spectrum bands to drown out the valid signals. Starlink, like cellular technology, uses excellent methods to operate amidst a lot of noise and find its packets, but it's still not immune to noise.
>
> Iran is a large area, and probably the government lacks the ability to block the entire nation simultaneously, but I would think they could drown out the signal in specific geographic regions, effectively jamming the signal entirely or almost entirely in those areas.
>
> Perhaps some of the cellular or satcom experts here can expand on or correct me if I'm mistaken. My physics knowledge on this has not updated much since the original spread spectrum work decades ago.

The original spread spectrum work concerned much much lower frequencies 
(in the MHz rather than the GHz) and the physics that goes with lower 
frequencies (not just spread spectrum) is that at the time, jamming was 
mostly used against receivers with fairly omnidirectional antennas. 
Read: It doesn't really matter where you transmit your interfering 
signal from - the receiver will hear it. It also helps that the (free 
space) path loss of RF signals is proportional to the square of the 
frequency, so low frequency means you can hit a receiver over a 
substantial distance with relatively little power.

Starlink is a different ballgame: It operates in Ku-band above 10 GHz. 
This means highly directional antennas - so you literally need to 
transmit into the receive beam from the beam's preferred direction to be 
able to jam at all. Plus having to invest more power to bridge the 
distance means that flooding just isn't an option here.

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Dr. Ulrich Speidel

School of Computer Science

Room 303S.594 (City Campus)

The University of Auckland
u.speidel@auckland.ac.nz
http://www.cs.auckland.ac.nz/~ulrich/
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