3 ms·

This would be real simple to prove, Starlink Satelites downlink on the same band as Satelite TV so you can use the receiver from a dish that downconverts it to

This would be real simple to prove, Starlink Satelites downlink on the same band as Satelite TV so you can use the receiver from a dish that downconverts it to something a cheap dongle can handle and put that all inside a grounded, metal box in the bed of a diesel and just record spectrum. I was under the impression that actual space business people had ways of not leaking RF when flying over.

defrost 2y ago
It's been proven by several teams already, eg: In new research accepted for publication in Astronomy and Astrophysics Letters, we discovered Starlink satellites are also “leaking” radio signals that interfere with radio astronomy. Even in a “radio quiet zone” in outback Western Australia, we found the satellite emissions were far brighter than any natural source in the sky. from: https://theconversation.com/starlink-satellites-are-leaking-signals-that-interfere-with-our-most-sensitive-radio-telescopes-215250 https://theconversation.com/starlink-satellites-are-leaking-... referencing: Detection of intended and unintended emissions from Starlink satellites in the SKA-Low frequency range, at the SKA-Low site, with an SKA-Low station analog (Sep. 2023) https://arxiv.org/abs/2309.15672 https://arxiv.org/abs/2309.15672 It's an ongoing issue in that Starlink v1.0 leaked and as I recall promises were made that the next generation of satellites would leak less and turn off when over radio quiet zones .. that second gen group have (IIRC) more noise and continuing transmitting over RQZ's.
- genewitch 2y ago
  > Although this IEMR abides by ITU-R guidelines, these intensities are large compared to the strongest astronomical radio sources in the sky and will therefore have the potential to disrupt astronomical observations at SKA-Low frequencies; Sounds like the ITU-R messed up, regardless of why. starlink is 28% of the EIRP the ITU specified. And the "newer generation are a factor of 12 fainter". We're talking micro. watts. of Effective Isotropic Radiating Power. with 0dBi antennas (unity gain). I don't understand why they're using those oddball frequencies, but i haven't paid attention to band allocations in a long time. 159.4MHz is Land Mobile band plan - "business band 2 meters", and oh, 137.5 is "SPACE OPERATIONS". I almost want to guess that the 159.4 is a spur of something down around 39.9MHz, fourth harmonic or something. I don't see anything that would let starlink radiate there, unless they change frequencies over countries. Furthermore, it doesn't seem like the 159.4MHz signals will be a detriment to the facility in question, but merely possibly impinge on radio-astronomers. I understand that these arrays are so sensitive that the RF they collect and process in the career of a scientist there is roughly equal to a cricket chirping once. or something. But microwatts are real tiny, too. Should be possible to put a notch filter at 137.5, or request space businesspeople to do intra-satellite on some other frequency.| in fact, business idea: aim a yagi array where the satellites are as they pass over, can be done programmatically, or reactively - at least 4 sensors however far from the facility monitor the starlink downlink frequencies (not 137.5 and 159.4, but the ku band ones) - and then aim at the satellite. I'll build it out with crap i have in my shed to prove it works if anyone is interested. If you know a satellite is in your second of sky, and you monitor, specifically, the 137.5 frequency with a separate, real sensitive antenna array, you can just drop the IQ/whatever from the radios for that timeframe. This isn't rocket science, QRM and QRN will plague us forever. Thanks, Marconi.

defrost 2y ago

It's been proven by several teams already, eg: In new research accepted for publication in Astronomy and Astrophysics Letters, we discovered Starlink satellites are also “leaking” radio signals that interfere with radio astronomy. Even in a “radio quiet zone” in outback Western Australia, we found the satellite emissions were far brighter than any natural source in the sky. from: https://theconversation.com/starlink-satellites-are-leaking-signals-that-interfere-with-our-most-sensitive-radio-telescopes-215250 https://theconversation.com/starlink-satellites-are-leaking-... referencing: Detection of intended and unintended emissions from Starlink satellites in the SKA-Low frequency range, at the SKA-Low site, with an SKA-Low station analog (Sep. 2023) https://arxiv.org/abs/2309.15672 https://arxiv.org/abs/2309.15672 It's an ongoing issue in that Starlink v1.0 leaked and as I recall promises were made that the next generation of satellites would leak less and turn off when over radio quiet zones .. that second gen group have (IIRC) more noise and continuing transmitting over RQZ's.

genewitch 2y ago
> Although this IEMR abides by ITU-R guidelines, these intensities are large compared to the strongest astronomical radio sources in the sky and will therefore have the potential to disrupt astronomical observations at SKA-Low frequencies; Sounds like the ITU-R messed up, regardless of why. starlink is 28% of the EIRP the ITU specified. And the "newer generation are a factor of 12 fainter". We're talking micro. watts. of Effective Isotropic Radiating Power. with 0dBi antennas (unity gain). I don't understand why they're using those oddball frequencies, but i haven't paid attention to band allocations in a long time. 159.4MHz is Land Mobile band plan - "business band 2 meters", and oh, 137.5 is "SPACE OPERATIONS". I almost want to guess that the 159.4 is a spur of something down around 39.9MHz, fourth harmonic or something. I don't see anything that would let starlink radiate there, unless they change frequencies over countries. Furthermore, it doesn't seem like the 159.4MHz signals will be a detriment to the facility in question, but merely possibly impinge on radio-astronomers. I understand that these arrays are so sensitive that the RF they collect and process in the career of a scientist there is roughly equal to a cricket chirping once. or something. But microwatts are real tiny, too. Should be possible to put a notch filter at 137.5, or request space businesspeople to do intra-satellite on some other frequency.| in fact, business idea: aim a yagi array where the satellites are as they pass over, can be done programmatically, or reactively - at least 4 sensors however far from the facility monitor the starlink downlink frequencies (not 137.5 and 159.4, but the ku band ones) - and then aim at the satellite. I'll build it out with crap i have in my shed to prove it works if anyone is interested. If you know a satellite is in your second of sky, and you monitor, specifically, the 137.5 frequency with a separate, real sensitive antenna array, you can just drop the IQ/whatever from the radios for that timeframe. This isn't rocket science, QRM and QRN will plague us forever. Thanks, Marconi.