Observation 9873098: Impulse-1 (LEO Express-1) (58301)

Satellites & Observations Observations
1

Regarding Observation 9873098 …

Does this look like a downlink transmit? @SA2KNG

2

It doesn’t look like the same transmitter, it has two distinct edges and weak trace in the center.
Like obs 9473199

3

Probably it is a LEMUR at that frequency. It will need some investigation to find which one is, as it seems we haven’t it in SatNOGS DB.

4

@SA2KNG Thanks for the comment, Any chance you are able to upload the spe-can waterfall for this pass for observation:

2024-07-17 15:50:50
2024-07-17 15:58:23

Thank you very much :slight_smile:

Max El on this pass was 5 and on Obs 9473199 max el was 52 deg so possibly not as strong as a signal strength due to elevation constrains? Just thinking outloud thanks!

5

Thank you for the comment! Can pull the TLE’s and plot them in respect to LEO-1 to see if there was one in visible range during that timestamp :slight_smile:

6

Do note that station 1888 is running other software to record Impulse-1, so all the satnogs observations is there to block access so any other observations doesn’t suddenly get interrupted.

This is the waterfall from 15:50 that would have been #9873100

58301_2024-07-17_15-50-53
58301_2024-07-17_15-50-53832×1603 103 KB

7

Thank you very much! Does the zoomed in portion here represent accurate Downlink transmit from the satellite? Thanks!

Capture
Capture236×1025 165 KB

8

Did that with ikhnos and none of the known satellites near Impulse-1 frequency, neither the Impulse-1, fit the signal curve. For example here is Impulse-1 expected curve:

2024-07-17T14:18:47_9873098_58301_23174AX_0-IMPULSE-1-MIRA_0.8059448148148078_B_r24.0_f0.0
2024-07-17T14:18:47_9873098_58301_23174AX_0-IMPULSE-1-MIRA_0.8059448148148078_B_r24.0_f0.0832×1603 437 KB

9

Thank you! The frequency, though shifted, in this picture below looks to follow that signature from the curve you drew up right? thanks! @fredy

Capture
Capture236×1025 165 KB

10

Unfortunately this isn’t Impulse-1:

  1. The pass was very low, according to the info in 9873100, so the signal shows up around 0-3 degrees elevation and it is very strong for such an elevation.
  2. The signal is shifted at least 20KHz from the expected central frequency.
  3. The signal, while strong, it disappears before the middle of the observation, which probably means that it follows a curve that goes outside the waterfall limits. If it was Impulse-1, the signal should be visible in a straight line during the whole observation.
  4. The signals in this observation don’t look like the signals of previous successful receptions. You can not see any peak on any of the signals at the edge and the middle of the signal.
1 Like
11

SatNOGS Network - Observation 9656721

@fredy @SA2KNG this observation shows a similar style of beacon activity with the same intensity as the one listed above… thoughts? Different pass geometry traveled between the two passes