Unable to seek advice from domestic sources.

BH9DFB_AI6YY

坐标美中，设备FTDX-10，CW甚至FT8在20m和40m都收不到国内信号，麻烦论坛老司机帮看看哪里出了问题。

最开始用的端馈离地3.5米左右，只能收到北美欧洲的信号；怀疑是发射仰角太大临时换了JPC-12，CW成功通联了澳大利亚新西兰日本还有韩国，而且信号强度都能有539-559，但是还是听不到国内的信号，想问问应该从什么角度下手比较合理？换天线？出城上山？谢谢

我这边夜间20M底噪不算太高，用JPC-12 CW带300Hz滤波器基本S表不起表，SSB能有S3左右。

BD8CCU

比较简单的办法是换高波段，15米10米；时间选择清晨或傍晚，灰线传播几率大

BH9DFB_AI6YY

BD8CCU There's actually a chance! I just went over and saw GP using FT8, and he was already at 15 meters. The signal strength is pretty good, but unfortunately, I tried to call him, but couldn't get through.

BH9DFB_AI6YY

BD8CCU Finally, I was able to contact BA5CW. Thank you very much!

BG5VLI

The signal traveling from within China to North America follows a route through the Arctic, which is highly susceptible to geomagnetic activity. This makes it difficult to penetrate reliably. It's recommended to try this during periods of low solar activity (e.g., when the sunspot number is low).

BH9DFB_AI6YY

BG5VLI Oh! So, looking at Australia in this way – since it doesn't go through the Arctic – means that it's actually quite different from the situation back home?

BI1SPD

I used to have trouble receiving signals from the US, but after changing to a different type of antenna (a "pull-rod GP"), it was slightly better. Now I can only connect to a few US local networks, and it seems to depend on the time as well.

BH7HQT

In North America, it's important to consider the weather conditions and local geography. Currently, I use GP (likely referring to a specific software or platform), and achieving stable 15W FT8 communication with North America is only possible in certain areas, such as Hawaii, Alaska, and parts of the US West Coast. Communication across the Eastern US has not been successful.

BG5VLI

BH9DFB_AI6YY Yes, the propagation path from NA/BY to Australia largely crosses the equator, with a stable ionosphere and minimal disturbances.

BG6QFO

I have also received a few 15-meter and 17-meter antennas through pull-over, which I believe were likely strong signals from the other side.

BA7NXE

Using FT8 at approximately 22:00 Beijing time, I can receive and transmit signals to North America via GridTracker, but the success rate is low.

CQ-BG8LTU

Try 15 meters between 9 AM and 12 PM Beijing time. I only managed to connect two North American signals last Saturday.

BG4TRF

I remember when we used to transmit on SSB at 20 meters, heading towards the North Pole.

BH7JUO

In Zone 4, likely in the US and China, the probability of successful SP (Single Sideband) operation on 15 and 10 meters between UTC 23:00 and 02:00 is high. The probability increases as winter approaches. Last year, I successfully used a 4-element Yagi antenna in FM mode at 29.6 MHz with 100W power to contact a station in the US West, achieving a signal strength of 59+10.

BH6BAS

I don't really get involved in FT8; I listen to it occasionally, and I can sometimes see the call signs from the US side.

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