Station Demoded Data Az/El Plot with data until 2019-09-18

Bellow you can see az/el plots by https://gitlab.com/kerel-fs/satnogs-AzEl-plots script of @kerel based on @pierros initial script . Data used for these plots were extracted from satnogs-network and can be found in their csv format in this zipped file: 2019-09-18.zip (9.4 MB) .

So in this diagram you can get an idea on which Az/El a station performs good enough to demodulate data. Have in mind that the sum of data (colored areas) are shown in logarithmic scale.

Data includes one entry for each data with unique timestamp of good observations with data. This means that data frames with the same timestamp are logged once. Also it doesn’t include data from png uploads, like SSTV or NOAA ones and CW decoded frames.

There are plans to have, in the future, page with stats like that but it needs some work before that.

For the past plots check this old thread.

Thanks to all for your contributions!


Station 1


Station 2

Station 6

Station 7

Station 9

Station 10

Station 12

Station 15

Station 16

Station 21

Station 22

Station 23

Station 24

Station 25

Station 26

Station 27

Station 28

Station 31

Station 32

Station 33

Station 34

Station 35

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Station 46

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Station 49

Station 50

Station 56

Station 61

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Station 65

Station 66

Station 67

Station 70

Station 72

Station 75

Station 77

Station 83

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Station 479

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Station 526

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Station 539

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Station 554

Station 555

Station 558

Station 567

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Station 569

Station 570

Station 572

Station 574

Station 579

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Station 642

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Station 692

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Station 702

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Station 749

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Station 888

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Station 909

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Station 918

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Station 930

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Station 939

Station 964

Station 966

Station 969

Station 972

Station 977

Station 981

14 Likes

Impressive. Mny tnx 73 Oliver

Hi Fredy,

This is awesome!

1 Like

A free drink at OSCW to the first person who can explain why most data is received between 10° and 40° elevation :smiley:

3 Likes

your latitude 55.634 ?

Correct, it is station 49 :slight_smile:

Do you know the answer, Alex? Or is this a true mystery?

My guess would be interference from the building where the antennas are located? As the yagi’s start to point more upward you are picking up interference off the back lobe?

2 Likes

Yes, I do have an answer, or at least a good guess :slight_smile:

At your latitude, you see a lot of satellites low on the horizon, is that it?

1 Like

I would say due to the fact that most satellite passes are in that range of elevation (assuming cut off at 10 for horizon).

It is logical to assume that if we do a graph for satellite occurrence per elevation it would be approximating an cumulative exponential distribution.

3 Likes

It’s the combination of distance and angular velocity. The angular velocity determines how long a satellite stays within a certain elevation range. Though the distance is smaller near zenith, the angular velocity is higher, so the satellite spends less time there. At very low elevations more time is spent there, but the distance is too far and hence the SNR to decode is lower.

8 Likes

Indeed, this is what I have been thinking too! You win!

That’s a good point, although, in such a case, I would expect the yellow band to be less symmetric in Azimuth. However, this is likely a contributing factor, so you get a drink too :grin:

2 Likes

This really helps my research on The Effects of Hyacinth Bean Vine on Moxon Takeoff Angles.

7 Likes

Hello,
how to extract data from satnogs-network for a station to create the diagram itself ?
I added a LNA and modified the configuration for station 972 and thus improved the number of decoded frames.
This will allow me to correlate the theoretical radiation pattern of the antenna with the decoded frame diagram


3 Likes

Great work Fredy, will look to elevate my antenna at the weekend given the plot the garage is obviously in the way
cheers

Max

1 Like

Unfortunately extract this kind of data currently is not easy for a user, I’ll try by the end of the week to extract and calculate the needed data for your station. :wink:

Thank you, I will look at the code satnogs-db and satnogs-network to better understand the data structure and perhaps bring new possibilities for users …

Just to be clear, there are ways to create these plots on yourself but it would take several requests on the API, what I’m doing is to use temporarily one of the backups of the database and run the script for generating the extra needed data (the ones attached on the first post) locally, the I run an extra script to draw the plots.

The plan is to create that kind of stats and others either in the site or maybe in https://dashboard.satnogs.org but unfortunately it’s not the number one priority, as we need to move forward with some more critical issues.

1 Like

This is definitely not an appropriate way of estimating the radiation pattern of your antenna, for various reasons (including satellite passes at different azimuths and elevations, different effective radiated power (ERP) by on-board transmitters, different downlink frequencies etc.).

A much better idea would be to try and center the main lobe of the antenna to an azimuth and elevation the sun drifts through (let me know if you need help figuring that out). The sun is a continuum (broadband) source which will allow you to map the radiation pattern of your antenna, without any tracking involved.

The antenna is also omnidirectional (the gain is a function of just one parameter (θ, or φ)), so that makes things even easier for you if you take that assumption into account (fewer measurements are necessary).

The gain will be normalized (it’s possible but a bit more work to calibrate/convert to dBi), but I think that’s what you’re looking for anyway.

4 Likes

Sort of relevant to something I started working on until classes got in the way. Using SatNOGS to study the antenna patterns of antennas on the network

This thread was also mentioned in my thread. :slight_smile:

I might work on that threads topic over winter break.

1 Like