Holding an Yagi to do satellite QSO is really tiring (both physically and mentally), and handheld antenna gain is generally not that high (for weight control). U7V5 is about as werght as an average person can hold it up for a satellite connection. On the other hand, in 2022, the University of Naples launched a MEO orbiting amateur radio satellite: GreenCube. It puts higher demands on antenna gain, and with up to an hour of pass time, hand-held antennas are simply not feasible.
After viewing the article written by BG7XWF, I decided to install a low-cost rotor for myself, which cost about C$78 (400￥).Links to articles he wrote. Thanks for him guiding me through the installation!
- Low cost: 301 cctv camera rotator +301 PTZ control box, capable of rotate two Yagi antennas with long no more than two meters.
- Heavy duty: Dahua heavy rotator /303 Heavy rotator + 303 PTZ control box, capable of rotate two Yagi antennas with long more than two meters.
The 301 rotator and 301 PTZ control box cost about C$48 (250￥) and carry 1.5m V7 Yagi + 1.8m U12 Yagi
I use a 2.5m sign pole to support rotator and antenna. buy a plastic bucket or a larger delivery box and pour cement into it and stick the pole upside down. finally, install the monitoring camera transfer plate, and install the screw on the rotator according to the hole position.
The antenna is supported by 2m Reker rods (epoxy tubes). purchase the M8x57 U-pipe card and punch two holes in the stick that fit just right.
Finally, pull a network cable between rotator and the indoor control box; cut off the RJ45 connector, peel off the cable, and connect the cable according to the logo of the cradle rotator and control box. the control box code switch corresponds to the baud rate and address code, please explore, I did not research out.....
Because the controller is too far away from my room to pull the cable. so I used the RS485 to network module to connect to my computer.
Open the following three programs: Orbitron, BG6LQV业余卫星软件, and virtual serial port software provided by the manufacturer of RS485 to network modules (not required if you are connecting to your computer using USB to 485 modules).
Click "云台通讯串口", select the serial port number, baud rate and address code, and click "打开串口"Open the serial port. If normal, the red circle on the right will change to green. Then click the "天线自动转向" automatic antenna steering button. After clicking it, it will turn into the "停止天线转向"Stop antenna steering button and start initializing the rotator. What a minutes,after this, the message "天线控制器初始化成功" will be displayed at the bottom of the software. You can click the "天线控制" antenna control button and use the up, down, left and right buttons inside to manually control the cradle head.
The most important step: After the initialization of the rotor, check whether the initial position of the antenna points to the north and measure the initial elevation Angle.click "云台参数"rotator parameter menu to set the"水平参数"horizontal parameters and "垂直参数"elevation Angle parameter, calculate with the following formula: millisecond/Angle of cradle head rotation. It is easier to calculate by manually turning the rotor to the end and then dividing the milliseconds displayed on the software by the maximum Horizontal Angle (350°).Then manually adjust the antenna to the maximum elevation Angle and measure the Angle. Elevation parameter calculation formula: milliseconds/(maximum elevation Angle - minimum elevation Angle) displayed on the software.
Select a satellite in Orbitron (never multiple satellites) and click the "绑定软件"bind software button in 业余卫星软件. Now the rotator can automatically track satellites.
After using it for a while, I felt that the antenna was not very good: Yagi was not long enough and the GreenCube satellite had a bad experience. Now the bearing weight of this rotator has reached the limit. If the antenna is upgraded, it must be replaced with a heavy-rotator. So I bought a Dahua heavy-duty rotator. Considering that VHF Yagi is basically only used for sending uplink signals, and the transmitting power can be increased to obtain better communication effect, only UHF Yagi is replaced.
I'll talk about this in the next post.
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