(This post was generously sponsored by BH6BEZ)😁）
Hello everyone, I'm BG6HJE. I'm from Lanzhou, Gansu Province, and currently live in Hefei, Anhui Province. I'm a beginner amateur satellite enthusiast. I'm glad you've all taken the time to read this post. Because I lack sufficient knowledge of radio communication, please point out any errors you find in the text. Or, if you have any valuable experience to share, please reply to this post so that we can learn from each other. Thank you!
On March 3, 2024, taking advantage of the favorable weather and rising temperatures, I arranged to try out the GreenCube amateur satellite with BH6BEZ. This satellite uses SSB digital mode.（PACKET)Therefore, a computer is needed to process the data. BH6BEZ provided the antenna and radio, while I provided the computer and software support. We are using an IC-705 and U7V4 Yagi antenna.
As everyone knows, when a satellite passes overhead, there is a Doppler effect that can affect our communication. The GC linear satellite is particularly sensitive to this effect. I and BEZ experienced this issue firsthand during the first transit at midday. We were unable to effectively manage the Doppler effect, and neither manual frequency shifting nor automatic software-controlled frequency shifting achieved complete synchronization. Manual frequency shifting was obviously not feasible given the precision required for frequency control.😂). Although the software automatically adjusted the frequency shift, it was still slightly behind Doppler's, which prevented us from decoding the satellite's downlink. Finally, just as the satellite was about to enter a shadow, BEZ successfully decoded it by manually adjusting the software.
With the experience we had gained, both I and BEZ were full of confidence and decided to have a thorough DX session in the late evening. However, things didn't go as planned; after adjusting the hardware, we encountered software problems. We received and decoded information from many stations, but we couldn't transmit. When we pressed the PTT and "F1"（CQ）The radio spectrum was completely clear, and no successful transmission was achieved.
So, we started troubleshooting the issue, suspecting that the SoundModem software was malfunctioning and unable to modulate information or transmit it. Unfortunately, at that time, we didn't have anyone experienced to guide us, so we couldn't find a solution. As a result, we had to pack up and return home without resolving the problem.
Ultimately, after discussing with BEZ and BA7LVG, they concluded that the DCD was being transmitted at too high a power level, which is why we were continuously prohibited from transmitting. The "abstract" appearance of the decoded image was also due to the radio signal being set too high, affecting the decoding performance.
There were also other minor issues, such as the data cable between the computer and the radio being unsuitable, and the software not having been properly tested beforehand. After summarizing our experiences, we decided to try again next weekend.
Finally, include a photo of BEZ's back as an advertisement space.🤪
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