Prepare tools and materials: wrenches, screwdrivers, closed wires about 3 meters long, protractors, audio and video cables, power plugs, etc.
Firstly, modify the parameters of the satellite receiver (connect the satellite receiver with audio and video cables and use the TV as a display);
Key points: modify two parameters-"downlink frequency" and "symbol rate".
1, through the channel button on the remote controller or satellite receiver, select the channel on CETV (either education 1, 2 or air class; Tip: Many channels are preset when the satellite receiver leaves the factory, including three programs of CETV.
2. Press the "Menu" button on the remote controller or satellite receiver to open the main menu directory, select "Program Settings" below to enter the next menu, and select "Program Parameter Settings" to enter the parameter setting panel. Only two parameters need to be changed: the downlink frequency is changed from "12620" to "12395" and the symbol rate is changed from "12395". Other parameters such as local oscillation frequency "1 1300" and polarization mode "vertical" remain unchanged. Press the "OK" button on the remote control to prompt whether to save the settings. Press the Save button to return to the Program Settings menu, select the Exit button, then return to the main menu and select the Exit button.
(Note: ① This work can be completed in the original working environment, that is, in the observation environment of SINO-1 satellite. Special note: When the parameters are changed and saved, the CETV program that can be received just now can no longer be received. (2) When modifying parameters, if the modification sequence is wrong, you can select System Settings in the main menu, enter Default Settings to restore to the original state, and then modify the parameters. )
Secondly, connect the satellite receiver to the satellite cooker and TV, and select CETV.
Important: Select any of the three channels of CETV.
Move the satellite receiver with modified parameters to the satellite pan/tilt and connect it with the satellite pan/tilt (connect the tuner with the satellite receiver with the prepared closed route of about 3m; At the same time, it is best to connect the CETV with the satellite receiver with audio and video cables), and select the channel (1, 2 or any one in the air, and there is no signal in the picture at this time; Tip: The parameters of these three channels have been modified before, because one channel has been modified before, and the parameters of the other two channels have been automatically modified, so the parameters of the satellite receiver are not modified here).
Three. Trilogy of satellite boiler debugging (key and difficult points);
1, adjust the tuner first (coarse tuning is enough, fine tuning is unnecessary).
Point: Turn clockwise about 40 degrees.
The debugging personnel stand in front of the receiver facing the satellite oven, that is, behind the tuner. At this time, the output cable interface of the tuner is basically vertically downward (towards the ground). Starting from this position, just rotate the tuner clockwise about 40 degrees (note: the standard degree is 42.3 degrees, because the tuner is insensitive to the angle and can receive signals with a phase difference of 10 degrees or even 20 degrees, so it is about 40 degrees.
2. Adjust the elevation angle of the satellite pot again (it is very critical and difficult here, and it must be accurately adjusted with the help of a protractor).
Key points: The actual elevation angle is 2 1.4 degrees.
(1) Understanding the theoretical elevation of Yibin City: The parameters obtained through the satellite search program and the satellite parameter data sent by it accurately provide that the receiving elevation of Asia-Pacific Satellite No.6 in Yibin City is 43.7 degrees (this is the elevation of the modified feed satellite pot, and the distance education uses the offset feed satellite pot, but the elevation of the offset feed satellite pot is different from that of the positive feed satellite pot, not 43.7 degrees. if
(2) Understanding the offset feed angle: Compared with the feed-forward satellite cooker, the elevation angle of the offset feed-forward satellite cooker we use is 22.3 degrees smaller (less) than that of the feed-forward satellite cooker.
(3) Obtain the actual elevation angle of Yibin offset feed satellite: actual elevation angle = theoretical elevation angle-offset feed angle = 43.7-22.3 = 2 1.4 (degrees).
(4) Debug the satellite pan/tilt and adjust the elevation angle to 265438 0.4 degrees. There are two common methods:
The first method: online measurement method tied to protractor (general method);
Drill a hole in the center of the protractor, thread it on the line, and then directly measure the actual elevation angle behind the satellite pot 2 1.4 (degrees) (see the left figure below).
The second method: measuring the angle of the iron frame (a method with strong applicability and operability, used in our county);
Calculated the angle of the hob =90-21.4 (actual elevation) =68.6.
First measure 68.6 degrees on a piece of paper with a protractor, and fold the corner of the paper with 68.6 degrees. Compare the angle of folding with the angle of hob, and adjust the angle of hob until it is the same as the angle of paper. If it is not intuitive and easy to operate to measure the angle of the iron frame with a protractor, it is very operational to fold the paper into an angle instead. See the picture on the right. ).
After the elevation angle is adjusted, fix it (it may be fine-tuned later, mainly because the measured elevation angle may be inaccurate).
The first method and the second method.
3. Then adjust the south deflection angle of the satellite pot (it is not easy to adjust with a protractor and compass, so we don't need to adjust anything).
Key points: If starting from due south, turn about 50 degrees from south to east. If you start from the direction of the original Sino- 1 satellite, turn about 37 degrees from south to east.
The south angle of Yibin receiving the Asia-Pacific satellite is 6-6: 49.9 degrees east-south.
Tips: Basically, all geosynchronous satellites are above the equator, and most of our China is located in the northern hemisphere, that is, the equator is in our south. Therefore, the satellite basins all face the geosynchronous satellites without exception, and they all face the south. Just because the longitude of geosynchronous satellites is different, there is a question of how many degrees in the southeast or southwest. )
The original southeast azimuth of SINOPEC-1 satellite was 1 1.84 degrees, and now it is 49.9 degrees, which needs to be adjusted by 36.86 degrees on the original basis.
Debuggers stand behind the satellite pan/tilt, and then adjust the satellite pan/tilt to the southeast (that is, to the left as shown in the figure) by about 36 degrees (note: programs can be received within the range of about 5 degrees, and if the due south direction is taken as the standard, it is 49.9 degrees southeast), and slowly move back and forth around 36 degrees (the reason why this work is put at the end is that the elevation angle can be measured with a protractor, but while observing the TV picture signal (while observing the TV picture) At this time, the signal intensity column appears on the TV screen, and the signal intensity is also displayed in digital form on the satellite receiver. When there is no signal, the display is between 15-25%, and the normal received signal is above 85%).
If you can't get a signal by slowly turning the satellite pot back and forth at this angle, go back and fine-tune the elevation angle, increase or decrease the elevation angle on the original basis, and repeat the above steps to find the stars back and forth, so you must find, receive and lock the program.
After receiving the program, we must fine-tune the southeast angle, elevation angle and polarization angle in turn, try our best to find the maximum intensity of the program signal and fix the satellite pot.
4. Set the parameters of the satellite receiving card on the computer:
Key points: modify two parameters-"signal frequency" and "symbol rate".
Select "Central Audio-visual Education Center" in the channel list, click the "Modify" button to change the signal frequency (the aforementioned "downlink frequency") from "12620" to "12395" and the symbol rate from "32553" to "27500".
It is best to restart the computer so that it can receive data normally (please remember to modify these two parameters when installing the computer system in the future).
In a word, the adjustment of satellite pot is the key and difficult point in the whole process. According to the order of tuner-actual elevation-southeast corner, you can easily receive programs. If not, it is necessary to consider whether there are tall buildings or obstacles blocking the satellite signal in the new direction after the satellite pot is adjusted. Only by reinstalling the satellite pot in an open place can it be debugged again.
Other parameters, such as the longitude of Asia-Pacific satellite 6 and the longitude and latitude of Yibin, will not be introduced here. The ultimate goal of providing these parameters is to determine three parameters of the satellite pot: polarization angle, elevation angle and southeast angle. We all know these three parameters, so we don't need to introduce these latitudes and longitudes.