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Equisat (The CubeSat you can see)

Discussion in 'Satellite and Space Communications' started by W5WTH, Jun 10, 2018.

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  1. KF5FEI

    KF5FEI Ham Member QRZ Page

    Exactly. Seems like every time we had a good pass, it was overcast or the light pollution was to great.
     
  2. W9GYR

    W9GYR Ham Member QRZ Page

    Not that I'm aware of.

    We know that it won't flash again until it exits this low power mode. We're hoping it will recover soon. The next increase in sunlight and power will happen around the 3rd week of October.
     
  3. W5WTH

    W5WTH Ham Member QRZ Page

    Thx and pls keep us posted! :)
     
  4. W9GYR

    W9GYR Ham Member QRZ Page

    Today we received the first packet since SatNOGS reported a reception on Sept. 29. The batteries are struggling with a lack of sunlight. This is the second recent dropout in communications and it was longer than the first.

    According to our orbital calculations: "winter is coming." This one should be brief and we expect to see a revival during mid to late Oct.

    Any reports of radio reception during this time would be greatly appreciated and will help us understand the health of the spacecraft. We expect that daytime passes will have a stronger signal and it might even go to sleep at night. It is 435.550 MHz with a 12.5 kHz narrow 4FSK channel. The doppler shift is +/- 10 kHz max. If the radio is too cold I estimate it could have a 0.5 to 1 kHz error in transmission frequency.

    After the next long "winter" in Nov. the satellite will then get the largest boost in solar energy that it has ever seen when the orbit lines up with the Earth's solstice.

    Thx 73


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    sunlight.png
     
    W5WTH likes this.
  5. K4KDR

    K4KDR Ham Member QRZ Page

    Nothing wrong with the transmitter on EQUiSat at the moment! Extremely strong signals on the 0355 UTC pass tonight.

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    -Scott, K4KDR
     
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  6. W9GYR

    W9GYR Ham Member QRZ Page

    EQUiSat has remained in low power mode for some time. It didn't revive as much as expected during the late Oct. increase in sunlight. We're now getting very little energy and the batteries are weak. Also our second ground station in Rome suffered damage from the recent hail storm and will be out of commission for a while. We would greatly appreciate any reception reports during the next month or so.

    We noticed that there is another satellite called SiriusSat-1 which is in a nearly identical orbit. It is currently about 500 km away and both are above the horizzon at the same time. It is transmitting at 435.57 MHz. Depending on the Doppler shift the two signals might overlap. The distance between the satellites is getting smaller and there will be a close approach on Nov. 5. Maybe within 5 km or less.

    I've written about this on my blog at https://blogs.brown.edu/umbricht/2018/11/03/close-approach/
     
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  7. W5WTH

    W5WTH Ham Member QRZ Page

    5km or less!!!! Any change they could touch?
     
  8. KA2CZU

    KA2CZU XML Subscriber QRZ Page

    maybe if they have real long antennas :D
     
  9. W9GYR

    W9GYR Ham Member QRZ Page

    These close approaches happen more often than you might expect. (Certainly more often than I expected. It seems low Earth orbit is crowded!) Lots of cubes are deployed from the space station in nearly identical orbits that occasionally cross.

    I rerun the collision analysis once or twice a day with the newest tle when an approach is happening soon. Below are my more accurate calculations from this morning.

    There's a 3.77 km close approach with Tanusha 3 later today. The probability of collision is about 1 in 3 million.

    The 2.91 km approach with SiriusSat-1 tomorrow has something like a 1 in 2 million probability of contact.

    Here's a closeup of the close approach at 21:33 UTC today showing Tanusha in red and EQUiSat is blue. They are almost on top of each other! Tanusha is slightly behind and about 3 degrees above us. The range to SiriusSat (green at right) will narrow to closest approach tomorrow morning. The Falkland Islands are shown for scale ;)

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    I don't worry too much unless it gets within the 1 or 2 km error bar of the tle.

    I was slightly more concerned about SiriusSat-1 transmitting on a frequency so close to us. Some of the SiriusSat-1 signals are within a few kHz. You can see how close in this SatNOGS reception. The chance of an overlapping signals is small but given we're now operating QRP (we're below 1/2 watt now) any rfi can impact reception.
     
  10. W5WTH

    W5WTH Ham Member QRZ Page

    Great reply. Thx for the education.
     

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