Shortly after successfully completing 144 MHz EME communication, I was able to achieve 432 MHz EME communication through a fortunate coincidence.
Self-generated signal characteristics:
I built a 176-element Yagi antenna, with a main boom length of 3.9 meters; gain of 15.5 dBi, and a front-to-back ratio of 35 dB.
The radio uses IC-910H, with a maximum output of 75W.
The cable loss is less than 1 dB, with the front-end amplifier BU435.
Using a Yagi antenna at my QTH, which experiences high noise levels, to conduct EME QSOs with DL7APV was successful. This was made possible by DL7APV's excellent antenna system. (Unfortunately, DL7APV passed away several months ago due to illness, and the amateur radio community has lost a great enthusiast.)
The two images above show the EME signal received from DK3WG in the park, using a 17-element 4-meter Yagi antenna. The IC-705 only receives (even if transmitting, 5W power is not sufficient to reach them).
Receiving is the most challenging part. Once the receiving problem is solved, and a signal can be received, it proves that the antenna system is functioning correctly. As long as an appropriate power level is maintained, two-way QSO (communication) can be achieved.
Summary:
1. The environment is very important, especially for weak receivers. Aim for a quiet environment with minimal noise. Don't slack off; the background noise at my park near the vegetable market is around S4, which is acceptable.
2. The feedline is a crucial component, and you should strive to maximize the performance of your feedline system. Don't ask questions like "What's the smallest antenna I can use for EME?" because communication is bidirectional. For example, DL7APV can achieve QSOs even with just a DP (dual-polarized antenna), and there are even very strong stations that can QSO without using a GP (general-purpose) antenna. However, in many cases, the opposing station isn't one of these extremely powerful stations. Therefore, maximizing your antenna system will increase your chances of successful EME operation. Foreign stations typically have gain of 20 dBd or more, often with multiple Yagi antennas stacked together.
3. Power is crucial, and the appropriate power level is essential for successful EME communication. If your noise floor is very low, you might be able to receive signals from the other end, but if your power is insufficient, they may not be able to hear or decode your signal. Therefore, while high power isn't strictly necessary, it's important to have enough. Ideally, you should aim for the highest possible power level; typical strong stations in other countries use power levels ranging from 500-1500W.
4. Radio. This is arguably the least important component, but it shouldn't be too poor. Most commercial stations currently available meet the EME requirements, including (but not limited to) stations operating on frequencies such as 857, 897, 9700, 7100, and 991A.
5. Front-end amplifier. This is a matter of personal preference; some people find it useful, while others don't. It's not essential, and in many cases, a front-end amplifier can actually have the opposite effect. It doesn't mean that you absolutely need one to achieve EME success.
6. Other aspects.
Pay close attention to minimizing every dB of loss, because your success may only depend on a difference of 1 dB.
Pay attention to the timing of the moon, identify the time periods with the most people for EME, and you can go to the chat room to discuss and observe; this is a good environment for new members to join. 432 EME Chat Room:https://logger.hb9q.ch/
Don't be afraid to try. Be proactive and contact strong stations. Often, strong stations will propose a time for an EME QSO when they themselves have a need for it. They generally won't go out of their way to do so, so even if you're very weak, you can simply start the QSO without hesitation. Don't be shy.
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