1:45 PM - 3:15 PM
[O08-P29] The observation of SporadicE using Amateur Radio
Keywords:Amateur Radio, SporadicE, 50MHz
[What is SporadicE?]
SporadicE is one of the phenomena occurred in E field of Ionosphere. It can reflect very high frequency (VHF), so we can communicate with people who is very far away in the frequency.
[Motive and Purpose]
SporadicE has been observed by a lot of methods. National Institute of Information and Communications Technology (NICT) has been conducting the observation called Ionosonde. To use Ionosonde, we can get the information about whether SporadicE occurs or not, but we can’t know where SporadicE is or what areas are connected by the SporadicE. Also, Ionosondes which NICT has are only 4 places of Japan, so we would not be able to observe all events that occurs in this country. One of the methods which uses GNSS is GPS-TEC. This is the way that calculates the total number of electrons and pint out the places where SporadicE occur. To use this method, we can research the motion of SporadicE precisely. However, the observation limits are limited to the SporadicE near the critical frequency of 17 MHz and the relatively strong SporadicE, and it is not possible to know which point-to-point propagation is caused by the SporadicE. The purpose of this observation is to obtain the data that where propagations are occurred by SporadicE, and to observe all the occurrence of SporadicE even if its critical frequency is under 17MHz by using Amateur Radio stations.
[The detail of this method]
I used 50MHz FT8-mode, both are used by Amateur radio communication. I observed the change in signal strength of amateur radio stations and get the information about the change of strength of SporadicE and which points are connected. Also, according to the address of transmit stations, I plotted the point which SporadicE was in the map. The observation point is at the rooftop of Meikei high school, and I utilized dipole antenna.
[Result]
Firstly, I show you the graphs that indicate the change of signal strength. (Figure2 and 3)
The graphs explain the change of radio wave so easily to understand. To look these data, we can know not only how long the SporadicE happened but also how big the event was to compare with each of duration of phenomenon. Also, it is possible to obtain the information where are connected by SporadicE so accurately, which is that only this method of observation can get. The challenge is that it is very difficult to distinguish between intermittent propagation caused by Sporadic E and by irregular repetition of transmission and reception by the radio stations. In addition, the antennas and output power of each station are also different, making to evaluate the scale of SporadicE with only one observation point. To overcome these problems, it is necessary to install stations that repeat transmission and reception at the same interval at multiple locations in Japan.
Secondly, I show you maps which indicate the places where SporadicE occurred. (Figure4)
Almost all the phenomena are expended to East and West or just a little south and north, and there were no one which were expended to precisely south and north. This result is same to the some GNSS methods’ one. In addition, it is possible to observe all the occurrence even if the critical frequency is under 17MHz. The problem is that the number of amateur radio stations is highly uneven in different regions, which makes the plotting interval wide and makes it difficult to obtain a general shape of the layer. The above issues can be overcome by To overcome these problems, it is necessary to use multiple types of antennas for observation and to install observation facilities in multiple locations throughout Japan.
[Conclusion]
To use FT8 mode, we can obtain the information which places are connected by SporadicE and where SporadicE occur. This new method will become an option of observation of Ionosphere.
SporadicE is one of the phenomena occurred in E field of Ionosphere. It can reflect very high frequency (VHF), so we can communicate with people who is very far away in the frequency.
[Motive and Purpose]
SporadicE has been observed by a lot of methods. National Institute of Information and Communications Technology (NICT) has been conducting the observation called Ionosonde. To use Ionosonde, we can get the information about whether SporadicE occurs or not, but we can’t know where SporadicE is or what areas are connected by the SporadicE. Also, Ionosondes which NICT has are only 4 places of Japan, so we would not be able to observe all events that occurs in this country. One of the methods which uses GNSS is GPS-TEC. This is the way that calculates the total number of electrons and pint out the places where SporadicE occur. To use this method, we can research the motion of SporadicE precisely. However, the observation limits are limited to the SporadicE near the critical frequency of 17 MHz and the relatively strong SporadicE, and it is not possible to know which point-to-point propagation is caused by the SporadicE. The purpose of this observation is to obtain the data that where propagations are occurred by SporadicE, and to observe all the occurrence of SporadicE even if its critical frequency is under 17MHz by using Amateur Radio stations.
[The detail of this method]
I used 50MHz FT8-mode, both are used by Amateur radio communication. I observed the change in signal strength of amateur radio stations and get the information about the change of strength of SporadicE and which points are connected. Also, according to the address of transmit stations, I plotted the point which SporadicE was in the map. The observation point is at the rooftop of Meikei high school, and I utilized dipole antenna.
[Result]
Firstly, I show you the graphs that indicate the change of signal strength. (Figure2 and 3)
The graphs explain the change of radio wave so easily to understand. To look these data, we can know not only how long the SporadicE happened but also how big the event was to compare with each of duration of phenomenon. Also, it is possible to obtain the information where are connected by SporadicE so accurately, which is that only this method of observation can get. The challenge is that it is very difficult to distinguish between intermittent propagation caused by Sporadic E and by irregular repetition of transmission and reception by the radio stations. In addition, the antennas and output power of each station are also different, making to evaluate the scale of SporadicE with only one observation point. To overcome these problems, it is necessary to install stations that repeat transmission and reception at the same interval at multiple locations in Japan.
Secondly, I show you maps which indicate the places where SporadicE occurred. (Figure4)
Almost all the phenomena are expended to East and West or just a little south and north, and there were no one which were expended to precisely south and north. This result is same to the some GNSS methods’ one. In addition, it is possible to observe all the occurrence even if the critical frequency is under 17MHz. The problem is that the number of amateur radio stations is highly uneven in different regions, which makes the plotting interval wide and makes it difficult to obtain a general shape of the layer. The above issues can be overcome by To overcome these problems, it is necessary to use multiple types of antennas for observation and to install observation facilities in multiple locations throughout Japan.
[Conclusion]
To use FT8 mode, we can obtain the information which places are connected by SporadicE and where SporadicE occur. This new method will become an option of observation of Ionosphere.