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Satellite tracking (BB_TRACKER V4.6    21_March_2013)

Aqui em Portugês     


How to install the driver on the Orbitron and  Dowload the Driver

KIT and printed circuit boards

Contact us for  more information

- PHOTO GALLERY to understand the idea

  Field day prototype test
(Thanks to GRC (Grupo Radioamadores Cascais)



The intention to enter the world of satellites and space at low cost, led us to develop a driver for the program Orbitron able to command two rotors of moderate price, thus, making a system for the following of Satellites, Moon, Sun etc. The complete system of components  hardware are purchased from the market and should not exceed € 400.00.

With the use of reasonable gain antenna, the system optimizes the contacts from horizon to horizon
and frees your hands.

The system consists of a
software driver that can be downloaded on the link page above.
This Driver extracts every moment
the Azimuth and Elevation of the satellite selected in Orbitron and sends them to a micro-controller board that will control the rotor-controllers through a system of LEDs indicators  PCBs installed over the rotor-controllers.

We are preparing a manual that explains how to
assemble all the kit, install it and operate.
In the following lines we describe the development of the idea for a Mule prototype being that, in the end, we will have  a system with 3 Printed Circuit Boards (PCBs) with all the electronics so, it just will be needed to assemble the parts according to the instructions manual.




Aspect of the  driver inside the ORBITRON

The green signaling shows compensation wich means that the Azimuth rotor is in a reverse rotation to avoid winding of the cables around the mast.
Before the compensation, this window previously notifies
the operator that will carry out a compensation by  coloring  orange.

The SINC button is active in orange color, when the driver is openned .
It is desirable, before the passage of any satellite, to do the compensation  and synchronization .


- Low cost system for satellite tracking.
- The system is a Kit that can be mounted by any ham with minimal knowledge.
- Driver works with Orbitron which is a satellite tracking program available for free downloading on the Net.
- Rotors used are type TV MASTERROTOR models B-747 or AR-303 which are well suited to the VHF and UHF antennas.
- The  system has a precision of + - 3 ° that is more than sufficient for the opening angles of the antennas with 13 elements.


The total cost
of the System wil be about  400.00 €.

- 2 rotors MASTERROTOR B747 AR303 to acquire in your local the market. (They are for € 50.00 each in Portugal.)

- Our KIT with 3 assembled PCBs, and accessories for  170,00 € (Packaging & shipment included).
Note: you will bee billed of VAT in your country customs

- Tripod or garden umbrella for about 30.00. Purchase it on your local market. We got our from Leroy Merlin

- For the power supply use any 12V 2A . We used an old PC powe supply . Or get one for about ~30,00 €

- Time and patience to assemble the kit cost  (€?).



- Rotors are low cost, so, at the end of a 360 ° movement some +- 5º comulative Azimuth error will happen .
However, this error does not affect the tracking of satellites with antennas openings of +- 6º at -3dB which are just the type of antennas we use for VHF and UHF for Amateur Satellite Comunications .
The antennas sh
ould  be installed so that, the center of gravity of the boom must stay on the elevation rotor, to avoid slippage.




1 - Use of an easy and friendly tracking satellite program ORBITRON

2 - Low price

3 - Suitable for use in tracking LEO satellites.

4 - To modify rotors, it is only necessary to open the azimuth rotor and saw the two locking pins.

5 - The system can be synchronized  and do not winds cables around the mast.It makes an automatic "Unrolling".

6 - The placement of the Led PCBs is simple: just remove the buttons and the contacts of the controllers  and place there the PCBs.

7 - The system allows anyone with minimal investment and ability to enter the LEO satellite communications

8 -
The system  can be also be remotly controlled by  entering the remote PC  over the Internet..




Hardware and software needed for the portable system.

2 ROTORS with Controllers(type MASTERROTOR B-747 or AR-303), 1TRIPOD (Quadripod), 1 TUBE with 1.5m



- 3 Printed Circuit Boards:
PCB/s with position LEDs for the Azimuths and elevations to mount in the controllers.

1 PCB Mother Board  equipped with a microcontroller to place inside the chassis, or box where will be all the assembly.
We have built
our prototype on a wooden board

One tripod or  an umbrella garden base




- An old
power supply can be used where we take  the 12 volt ~ 2 A minimum.

5  Flat Cables with 16-conductor with 2 x ICD16 female connectors to connect the microcontroller PCB and the Led position PCBs.

2 x 10 meters of cable  UTP CAT5 4 pairs to send the control voltages to the rotors. With 2 Power connectors and one DB15 male connector.

( You can avoid the multipin connectors, connecting the cable directly to the Rotors terminals 1,2,3).


- 1 Driver
with free  Download here to be installed in the PC following the instructions.




The program BB_TRACKER is a Driver that runs under Windows
and  is inserted in the Orbitron configuration.
The driver receives data from Orbitron and sends them to
the PCB equipped with a microcontroller that commands the controllers of the rotors for the azimuths and elevations.
The rotors and
the controllers have synchronous motors.
For azimuths
, we made a printed circuit board with 60 position green LEDs in circumference at  6 degrees angles (Sectors of 6º) which are sufficient to maintain tracking of satellite antennas with lobes of + - 3 degrees @ -3 dB.

he elevation PCB have  15 LEDs corresponding to  15 sectors of 6º.
In the rotating disk
of the controllers we installed a photodiode which detects  the LED light stopping in the center of the respective sector.
The software always calculates the shortest route around 360 degrees and walk accordingly.
The program also warns that will carry out a reset of turns
for compensation,
in order to avoid winding the cables around the support of the antennas.





The Hardware simulates manual operation of the controller receiving commands from the software and do the following:
1 - Turns on the LEDs of the azimuth and elevation where the rotors should move
2 - Connect
s the current supply of the drivers on both rotors through the relays RL1 and RL2
3 -
Actuates the relay RL3 and RL4 to define the direction of the rotors movement : In azimuths if it is CW or CCW. In the elevation if it is 90 ° upwards (UP) or down to 0 ° (down).

When the photo diode
reaches the lighting LED, it  sends an information to the microcontroller  to disable all the devices previously activated.

The relays RL5 and RL6
are intended to cut off the current from the rotors keeping the
controllers working to synchronize the system.


The software acquires the data automatically from the Orbitron processing them as follows:
- Extracts the data through the protocol DDE (Dynamic Data Exchage) in a
Satscape string format.
- Insert
s data in the reading windows for viewing.
- Process
es the data from windows comparing the values with the ranges of sectors and sends a related signal to the angle-LED  where the Micro should send the rotor, the LED lighting sector
- The software also compares current data with the previous one to  know which way is shorter to move the rotor (CW or CCW).
It also  calculates the number of sectors CW and CCW to where the rotor will be sent. It calculates the travelling of the azimuth rotor to notice to do a RESET and avoid cable turns around the mast.  
- Even after turning off the PC, the data
of the Last Position of the antenna is stored.
- In the case of the Last Antenna Position values indicated by the  program does not match the actual orientation of the antenna, it is because something has been forced.

To fix it, just press the knob SYNC (when in orange) that will synchronize the system .


System buttons

- Button-Start / Stop to trigger the automatic tracking
from Orbitron data.

- Start-button to activate the manual system
with the windows where are inserted  the intended azimuths and elevations.

- Button-SYNC to synchronize the actual orientation of the rotors with the controllers.





It uses a Software Driver running with Orbitron, a microcontroller in a PCB accessed by the PC USB port, which controls the modified Controller Box.

The Software Driver receives data from Orbitron processes it and sends the commands to the microcontroller which, in turn, sends data control to the Rotor Controller.



The concept is to replace the original controller button with an hardware which simulates the manual operation.

This is done replacing the rotable controller dish with a PCB with leds which represents the centre of  angle sectors.

In the white plastic rotable dish we put a photodiode which detects the activated led and stops.

We divided one complete turn of 360º in 60 sectors of 6º each for the azimuths and 90º 15 sectors for elevations.


The reason for the sectors is to permit an antenna pause between +- 3º of satellite passage inside a 6º arc.

For example: the sector 5 will be between 24º and 30º and the antenna will be pointed in the midle  27º during the passage.


As soon as the satélite azimuth is out of the sector, the software driver sends a command to the microcontroller to activate the next sector led and the (white plastic) dish of the controller runs 6º and stops.





The driver catches the data from Orbitron with the DDE protocol in the Automatic mode or catches data from the windows in the Manual mode.


The movement of the azimuth rotor is free from any mechanical limitation so, it will be possible to turn more than 360º around without being interrupted in the middle of a  satellite pass .


 However, the cables that feed antennas are not to be wrapped around the support. The software will reset automatically back 360º the orientation of the antennas whenever it reaches a complete cable turn around the support.


To prevent that automatic resets occurs during the satellite passage, the RESET button will become Orange to recommend a previous RESET before the satellite horizon view, allowing tracking it completely without the interruption of a reset.


In the Manual operation, the Azimuth and Elevation are inserted in the windows to command the antenna position.

The SINC button is to synchronize the physical antenna position with the system data. It can occur with heavy wind or data loss and the software position do not corresponds to the physical antenna position.

















NOTE : This type of Rotor is not recommended to work horizontally. However its use has no revealed mechanical damage declared.
The only care is to balance the antenna placing it to the rotor in its center of gravity




We fixed the Elevation Rotor horizontally more efficiently, taking advantage of the clamp  and making new  holes that allowed to put it as shown







 Interior of Rotor controller with synchronous motor and rotor button.

These contacts in the controller will be substituted by relays






                                                      Contacts removed                                                                                                                         Aligning the PCB




                                       Marking holes for the leds                                                                                                                      Drilling of small holes



 Drilling for the leds. Error of + - 1 degree are acceptable. It is very difficult to accurately drill the holes.  Images for Azimuth PCB with 60 led holes and elevation with 15 holes + 2
In the final stage, holes will be precisely placed by a PCB software design and professional PCB manufacturer.( SEE IT HERE )






Placing the 60 LEDs on the disk of the azimuths AND 15 LEDs on the disk of the elevations.                                           Phototransistor and shrink sleeve




Sleeve placed on phototransistor                                                                                                     Pin where to put the phototransistor


Phototransistor placed . Screws were removed because are not necessary. The sleeve stands the fototransistor.           Photodiode will run down and around the leds.



15 Elevation diodes placed. ( Note:Each diode representes the center of a sector of 6º  )                                  Flat cable 16 connected to the Microcontroller PCB



For Azimuth we have 60 sectors ( 60 leds) divided in four quadrants of 15 sectors.                       Four flat cable 16 wil connect diodes to the microcontroller PCB


Note : These two PCBs are a prototype design and will be replaced by the new comercial PCBs shown above.



Assembled system to put in to a metalic box


All Relais, and wires, will be placed in a single PCB after this prototype




Since this is a prototype, to make changes and corrections, the assembly of the circuit is quite triky  and we used flat cables. After testings a double-sided PCB will be built.





Remove the blocking pins in the gear to allow more than 360º rotation of the Azimuth rotor




 This is the gear of the rotor shaft










Exterior microswitch installed in the Azimuthe Rotor. The cam (ledge) switches on the stop at zero. The Brown and Brown/White wires belongs to the UTP CAT5 cable.





Wiring the UTP cable to the rotors. In both rotors, connections are the same.




Connectors used and glued to the rotors to allow easy transportation.                      Soldering the female pins of the connestors

Note : These numbers are the numbers of the Pin connectors and the number of the DB15 Pin also. They are note the numbers of the Rotor terminal.

As seen in the picture before;:
The Blue cable will connect to the pin 2
The Orange to the pin 1
The Green to the pin 3  .
The Brown and White/brown wires will connect to the microswitch opened contacts in both rotors.





Soldering the two UTP cables (Azim.and Elev.) to the DB15 male connector             Soldering the internal wires to the female of DB15 connector






Back view of the prototype Box. 




Top view




BB_TRACKER, Antennas, Rotors, Tripod, Mast and Radios ready for a Satellite Field Day...


73 have a nice work