Satellite FUN is a C# application which predicts satellite passes , tracks satellites, automatically starts RF recording (HDSDR) and post-processing (SatDump). The goal is mainly unattended Weather/ Earth observation satellite reception on L and X band . It supports the SPID BIG RAS including the HR version through the Rot2Prog protocol and other rotators through HamLib.

Here is a direct link to Github !

Satellite FUN is just a hobby project written to suit my own needs for satellite tracking , especially on X band , where accurate antenna positioning is very important. If you find it useful, please send me a message and report bugs etc ! THANKS !!!

Satellite position calculation is done using David Taylor’s DJTSatLib.dll

Regarding antenna tracking, in the Rot2Prog protocol case , it writes commands directly to its serial port , which allows for faster position update. This mode is what I use on X band , allowing position update every 0.5s.

HamLib tracking is somewhat slower, as by default position update interval is set to 3s (can be further reduced though). This may already be more than enough for many applications though.

Some other features have been added to aid Weather/Earth observation Satellite RX and enable unattended pass-list tracking / recording/decoding:

-One can automatically launch HDSDR with the proper settings per satellite.

-It programs the 54 MHz -13 GHz Kuhne MKU Local Oscillator.

-Antenna pointing offsets can be changed on the fly.

-There is a favorite satellite list with Satellite TX frequency, Recording sampling rate etc

-Latest version can also track the whole pass-list enabling automatic recording with HDSDR .

– Automatically launches the appropriate SatDump demodulator/decoder and stores resulting files in a dedicated folder.

– Can reset Lime’s driver or power-cycle it using the RTS signal of a COM port. This is useful when Lime occasionally hangs . With this feature it will be restarted just before the satellite becomes visible.

-Switches antenna polarization using the DTR signal of a COM port. This signal can go to a coaxial switch and select RHCP/LHCP.

You can download it from here .

Locate the green “Code” button and click and “Download ZIP” file:

Unzip the contents and you will get 2 folders , one containing Satellite FUN and another one with HDSDR ExtIO dlls.

I have added software limits to Satellite FUN and these should be adjusted first but as an extra precaution it is best to set some limits for AZ and EL on your controller as well to prevent overturning beyond physical limits. My antenna is placed on a balcony and from here I can only track eastern passes with AZ>0 and AZ<200. In addition , EL movement must be limited to 0 up to 90 degrees otherwise the dish will hit the wall :-). For these reasons, I have set the limits on my Rot2Prog controller accordingly. These limits on the controller side rescued my dish a couple of times during software debugging 🙂

I have included the Airspy ExtIO dll and 2 ExtIO dlls for the LimeSDR.The official one (ExtIO_LimeSDR_1.07.dll) supports sampling rates up to 30 MSPS.Jean-Luc Milette kindly granted permission to include his custom dll (ExtIO_LimeSDR_WxSats_to_share.dll ) which supports rates up to 60 MSPS. Many thanks Jean-Luc for providing these! These dlls should be pasted to the HDSDR folder .

Satellite FUN installation should be done as an administrator.

You first need to install and register the DJTSatlib.dll.

Follow the instructions further down below.
Once the dll is installed, start the program, hit yes to the “Update keps” pop-up message, edit your lat/long etc. One can also edit the config.txt file directly. For the new settings to take effect , it is always good practive to save the config.txt file and then restart the program !

For HAMLIB use , you need to edit rotator.bat
For example , for my old Rot2Prog BIG RAS controller , I just have 2 lines.
rotctld -m 901 -r COM4 -s 600

For SPID BIG RAS HR (MD-02), just these 2 lines are needed after editing your com port and connection speed:
rotctld -m 903 -r COM4 -s 19200

The program does not automatically connect to your rotator.
Connect to your rotator either directly using Rot2Prog or using HamLib (launching rotator.bat)
Then try to read back its position to see that it works.
You can use the GO TO AZ/EL buttons to check it goes where instructed.
To track a satellite , once it is visible , hit the auto-tracking button.

Please open the config .txt file and edit the paths to HDSDR and HAMLIB as required. You will find the lines below:


HAMLIB_BIN_PATH %PROGRAMFILES(X86)%\hamlib-w64-4.1\bin\


For automatic HDSDR launch with the proper dll, sampling rate and recording folder, some preparatory work is needed to create the profiles and store them in registry .

To do this, select a dll from “Select ExtIO dll” and a sampling rate from the “SR (MSPS) ” combo-boxes. Then hit “Launch HDSDR now “. When HDSDR starts, select the corresponding sampling rate, edit recording folder , gains etc and then exit. Repeat this for all sampling rate and dll combinations. These will be stored in the registry and from now on loaded automatically.

Please keep in mind that this is work in progress. I use it almost everyday to track satellites and record /decode passes and will try to fix every bug I am aware of !

Regularly check for updates on Github and please report bugs etc .


Follow the instructions below to install the DJTSatlib.dll.

On 64 bit systems:

First copy the DJTSatlib.dll to your Windows\SysWOW64 folder and
register the dll being in that folder. This can be done as follows :
Open a cmd window as Administrator –> Start/All Programs/Accessories .
Then Right click and Select “Run as Administrator”.
Then change folder to Windows/SysWow64 by typing :

cd C:\Windows\SysWOW64

Now type:

regsvr32 DJTSatlib.dll

On 32 bit systems:

Enter the unzipped folder and double-click on “install djtsatlib.bat”.
This is only needed once, when the program is installed for the first time.
If this does not work try the following:
Copy/paste the dll into Windows/System32 folder and register the dll in there.
This can be done by first opening a cmd window (Start/All Programs/Accessories).
On W7 cmd must be opened as admin so Right click and Select “Run as Administrator”
In the cmd window that has just opened, change folder to Windows/System32
by typing :

cd C:\Windows\System32

Now type:

regsvr32 DJTSatlib.dll

Important Note:

Windows 7/8/10 users must be administrators to successfully register the dll.


Some screenshots can be found below :


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