vsat

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Using a VSAT terminal for EME

Some time ago I managed to get a Ku band VSAT terminal

After a long time in storage I started to try and see if I can use this for EME on 10 GHz.

At beginning I found a problem that elevation was not working, the stepper motor for elevation adjustment was not working.

After repair of the stepper motor the whole system worked fine and now I am trying to find a way to auto track the moon.

Here you can see a small movie from the VSAT Dish moving on my commands.

The system is a 1 meter dish with a RX LNB and a Ku band up converter max 4 Watt output.
A Tracking antenna control unit communicating with the Stabilized antenna pedestal with built-in GPS
The whole system came to me without any documentation so I searched the internet for available manuals
Thanks to Google I found a manual from the Tracking antenna control unit but not the exact manual for the antenna pedestal.

First I tried is to power up the Tracking antenna control unit, a sticker on top of the unit said factory set for 220 V so just connect to mains and power up, a loud noise came from the unit and after a few seconds it stopped. The power fuse had blown.
I checked the internal fuse and it was blown, then I checked the transformer inside the control unit and found that the fuse box was set for 110 Volt. I put in a new fuse and  set the fuse box for 220 Volt and tried again to see if it was working. Now with success, the Tracking control unit seemed to work.

 

As I did not know what power supply the antenna pedestal unit needed, I started to open up the unit connected to the external power switch.
There I found a power supply from 110-220 Volt input and 24V DC output. So it was safe to connect this on 220 Volt power supply.

I then had to find out how the Antenna pedestal unit would communicate with the tracking antenna control unit, it needed a interface box which I also have and a RS232 cable. After I found how the system should be wired I started both systems and and the initial start-up phase moved the antenna in azimuth and elevation, so it looked to work.

I then tried to find the way to change azimuth and elevation and found that azimuth was working but that the elevation was not responding to the commands inputted at the Tracking antenna control unit.
Some search followed and I became the idea that the elevation stepper motor was not working.
I dismounted the stepper motor and found that it was impossible to turn the motor.
With some high force I was able to turn the motor but this did not look correct to me.
I sprayed the motor with a bit of oil to lubricate and it seemed to help. After some turning the force needed to turn the motor became less.
Then I tried if the motor would turn when feeded with power from the antenna unit, and yes it did turn in steps.

After I remounted the stepper motor the antenna responded to the commands from the control unit and the system seems to work.

Now I have to find a way that the antenna can be linked to a computer to steer it automatically to follow the moon or the sun.
This is at this moment the major problem to solve.

It is communicating through RS232 so I will try to see if I am able to understand this communication

 

The VSAT Dish in the radome

The dish with antenna pedestal will be installed inside a radome which I also have, unfortunately I miss the lower part
of the radome but I think this can be solved using a brick wall


Radome transport

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