Original post:https://www.hellocq.net/forum/read.php?tid=378362(Author BG7NF)
In the world of amateur radio, every long-distance communication experience on the 2-meter band is a wonderful adventure. Since entering summer, there have been very few instances of successful long-distance communication in the Pearl River Delta on the 2-meter band, with only sporadic reports from areas 1, 3, 4, and 5, as well as BV. This contrasts sharply with previous years, causing considerable concern due to the delayed opening times. June 13th was a memorable day. Several long-term 2-meter enthusiasts in the Pearl River Delta, including BD7OH, BD7IS, BG7IKK, and BD7NWF, successfully communicated with numerous Japanese radio stations using the FT8 mode on the 2-meter band. My longest successful communication today was with JA7WXL, a friendly station, at a distance of 3275 kilometers. This is truly remarkable. Furthermore, the communication lasted for almost 4 hours, during which I also successfully communicated with radio stations in areas 4, 5, and 6 within China. The excellent communication results were a great surprise to us.
2-meter band, with a frequency range of 144 - 148 MHz, as a very high frequency.（VHF）A typical example of a frequency band, under normal conditions, signals primarily propagate via direct wave over line-of-sight. The ionosphere has minimal reflection effect on these signals, and they can also easily generate reflected waves when encountering obstacles, making them generally suitable for short-range communication. The ability to achieve long-distance communication likely stems from specific propagation conditions at play.
The sudden occurrence of an ES (likely referring to a specific event) before the arrival of Typhoon "Butterfly" may be a key factor.
Vertical wind shear is one of the key drivers for the formation of the Es layer. In the E region of the ionosphere, significant differences in wind speed and direction in the vertical direction can lead to strong turbulent motions. This turbulence can concentrate charged particles, thereby forming regions with high electron density in the Es layer. For example, when the wind speeds and directions at different altitudes in the upper atmosphere are inconsistent, similar to vehicles on different lanes traveling at different speeds and frequently changing lanes, this causes atmospheric matter to rub against each other and collide, leading to the concentration of charged particles, which creates conditions for the formation of the Es layer.
The transmission time today started at 00:31 UTC and lasted until 04:00 UTC, a total of 3.5 hours. Theoretically, this is similar to signals transmitted through atmospheric ducts, which are relatively stable and can last for several hours. However, considering the distance of over 1000 km, it's closer to the characteristics of ES transmission. It seems that the "Butterfly" typhoon in early this year enabled communication at a distance of 2 meters in the Pearl River Delta, which is truly amazing.
This recent experiment significantly expanded our understanding of the characteristics of propagation in the 2-meter band. The results achieved today once again demonstrate that, under specific meteorological and ionospheric conditions, it possesses the ability to achieve long-distance communication across borders. We can now deeply appreciate that, in this field characterized by uncertainty, unexpected breakthroughs are always possible. Through patient observation and active experimentation, we can achieve unforeseen results in the complex and variable 2-meter band propagation environment. We can further investigate the relationship between different meteorological conditions, ionospheric states, and 2-meter band propagation, and explore more methods for achieving long-distance communication under special propagation conditions. Furthermore, we look forward to having more opportunities to utilize these special propagation conditions, allowing us to continuously expand the boundaries of amateur radio communications and discover even more wonders in the world of radio waves.
闽ICP备2021006864号-7
闽公网安备35020602002794号