@proceedings {1053, title = {The Influence Of Solar Activity On High-Frequency Communications: A Systemic Risk To Global Communication}, year = {2026}, month = {03/2026}, publisher = {HamSCI}, address = {Newington, CT}, abstract = {

Radio blackouts, phenomena resulting from the interaction between solar activity and the Earth{\textquoteright}s ionosphere, constitute an invisible and underestimated societal risk with significant potential to impact High-Frequency (HF) communications. Such communications are vital for the safety and operation of aircraft, maritime vessels, broadcasting systems, emergency services, and amateur radio networks. This study was conducted by seventh-grade elementary school students from a public school in Santa Catarina, Brazil, as a research project within the Civil Defense in Schools Program. Its objective was to record the frequency and intensity of radio blackouts, aiming to assess the viability of a low-cost approach for Disaster Risk Reduction (DRR) education by integrating space weather risks into the educational environment. The methodology employed consisted of data collection from May to December 2025 using the Space Weather application. Data were recorded whenever the application issued a notification regarding an event occurrence. These events were classified according to the official nomenclature of the National Oceanic and Atmospheric Administration{\textquoteright}s (NOAA) Space Weather Prediction Center (SWPC), which categorizes solar flares into three classes (C, M, and X) and radio blackouts on an intensity scale from R1 to R5. An average of 12 monthly occurrences were recorded, including a high-intensity X2.62-class blackout in May, which was registered and reported by various news outlets. The results confirmed the fluctuating nature of solar activity during the analyzed period. While it was not possible to directly correlate the recorded events with specific communication failures documented in amateur radio logs, NOTAMs, or NAVAREA Warnings, the study underscores the relevance of promoting research and employing low-cost tools for the educational monitoring of space weather phenomena. This approach effectively illustrates the connection between solar activity and the vulnerabilities of modern technological infrastructure. By overlaying blackout-affected areas with major air and maritime routes, the systemic nature of this risk is reinforced. For future work, it is recommended to correlate these observational records with communication failures effectively reported by critical sectors, aiming to deepen the understanding of operational impacts.

}, author = {Alexandre Takio Kitagawa and Rebeca Wegner Geisler and Kathellen Thayenne Pereira Nogueira and Emillin Rocha} } @proceedings {1052, title = {Unauthorized Use Of Military Satellites: Threats To Mission Security And Integrity}, year = {2026}, month = {03/2026}, publisher = {HamSCI}, address = {Newington, CT}, abstract = {The clandestine and unauthorized use of military communication satellites, colloquially known as {\textquotedblleft}Bolinha{\textquotedblright} (portuguese for {\textquotedblleft}Little Ball{\textquotedblright}) in certain regions, constitutes a significant and escalating threat to mission security and operational integrity within the space domain. These geostationary satellites, such as the U.S. Fleet Satellite Communications System (FLTSATCOM) and UHF Follow-On (UFO) systems, were originally designed exclusively for military communications. However, their reliance on simple, non-regenerative {\textquotedblleft}bent-pipe{\textquotedblright} transponders, operating within the UHF band (approximately 260 MHz), has rendered them vulnerable to misuse and unauthorized appropriation by civilian users. This misuse has been particularly well-documented in remote areas of South America since the 1990s. This research aims to verify the current prevalence of unauthorized civilian use of these satellites and to raise an alert regarding this ongoing situation. The methodology employed involved a receiver (UV-32) paired with an antenna of 5/8 λ to capture the specific frequencies utilized by the satellites. Reception tests were conducted at random times, without a predefined pattern. A total of eleven different frequencies were analyzed between 244.125 and 258.545 MHz, which were identified from video streaming websites. The findings indicate that reception was achieved on all listed frequencies. The audio content, delivered in Portuguese, clearly contained dialogues that were outside the context of the satellite{\textquoteright}s intended military application. Analysis confirms that these illegal transmissions, which are frequently associated with illicit operations, generate detrimental interference. This parasitic load degrades legitimate military signals, saturates transponder capacity, and, critically, accelerates the drainage of the satellites limited onboard battery resources, resulting in numerous operational disadvantages. While operational countermeasures, such as the targeted {\textquotedblleft}jamming{\textquotedblright} of pirated channels, are utilized, the definitive solution lies in technological migration. Modern systems, such as the Mobile User Objective System (MUOS), which feature robust encryption, regenerative processing, and spread-spectrum techniques, are inherently more resistant to unauthorized use. In conclusion, containing this illicit practice is not merely a matter of public safety, but a critical necessity for the responsible stewardship of the space environment, the protection of national security infrastructure, and the preservation of public investment in space-based capabilities. }, author = {Alexandre Takio Kitagawa} } @proceedings {954, title = {Investigation of Electromagnetic Wave Propagation in CB Radio with Elementary Students: A {\textquoteright}Super Bowl{\textquoteright} Mystery}, year = {2025}, month = {03/2025}, publisher = {HamSCI}, address = {Newark, NJ}, abstract = {

The Citizen{\textquoteright}s Band Radio Service (CB Radio), as defined by the United States Code of Federal Regulations, is a two-way voice communication service operating in the 27 MHz band, divided into 40 channels with a power limit of 4 Watts. Classified as High Frequency (HF), CB radio shares the spectrum with other services, and in Brazil, it offers similar functionalities with simplified registration. Motivated by the accessibility and low cost of equipment, elementary school students in Santa Catarina (-26.8668712, -49.2317786) conducted an experiment during lessons on electromagnetic waves. Using Aquarius RP40 and PRO401HH CB radios, the students received signals on channel 06 (27.025 MHz) in Amplitude Modulation (AM), identified as originating from the USA and related to the {\textquotedblleft}Super Bowl{\textquotedblright} broadcast, through the analysis of the message content. After researching the possible source of the transmission, it was found that the signal travels approximately 7,850 km from its origin to the receiver, a distance estimated using geolocation tools and information from possible broadcasters found online, demonstrating the propagation of HF waves through the ionosphere. This region of the upper atmosphere reflects radio waves back to Earth, enabling long-distance communication through multiple {\textquotedblleft}skips{\textquotedblright} between the ionospheric layers and the Earth{\textquoteright}s surface. The observed variation in the received signal intensity, consistent with fluctuations in ionospheric electron density, highlights the influence of the ionosphere on signal propagation. Although long-distance reception may raise questions about transmission power, antennas, and other factors, this study emphasizes the role of the ionosphere, providing students with hands-on experience with radio communication equipment, deepening their understanding of electromagnetic waves through the ionospheric layer, and inspiring scientific inquiry.

}, author = {Alexandre Takio Kitagawa and Anni Carolini Maffezzolli and Ana Carolina Hemmer de Oliveira and Emanuella Brandl} } @proceedings {878, title = {Quality of AM Radio Reception at Night and Daytime for Future Use in Natural Disaster Situations}, year = {2024}, month = {03/2024}, publisher = {HamSCI}, address = {Cleveland, OH}, abstract = {

Brazil has more than 10,500 radio stations, which broadcast live sports, music, services and entertainment. It is estimated that 86\% of the Brazilian population listens to radio programming, making it, therefore, a more adaptable communication vehicle for use in different media and situations, such as the possibility of using it to transmit alerts and warnings in situations of natural disasters. The objective was to compare the propagation of AM radio transmissions at night and during the day with commercial receivers, also, to prove, with a simple methodology and at a reduced cost, problems and advantages that may occur in transmissions on the aforementioned frequencies, instigating research scientific research with students from an elementary school in Brazil. The receptions were carried out by the students during the day (9:00 and 12:00) and at night (7:00 and 00:00) using two receivers, one powered by batteries and the other by a battery (car receiver) and recorded for later group analysis adopting the SINPO code methodology. The results showed that several commercial AM radio stations were received at night, but during the day it was not possible to receive reception at any of the times analyzed. During the night, many distant stations could be captured, which negatively influenced the reception of the stations studied, but could be used to explain the propagation of the electromagnetic wave, the presence and performance of the Ionosphere and its characteristics. Due to the propagation behavior of the electromagnetic wave of AM radio stations, which has some peculiarities when compared to commercial FM stations, the use of this band in the region under study, in the case of alerts and warnings of natural disasters, must be better analyzed to ensure satisfactory results are obtained.

}, author = {Alexandre Takio Kitagawa} } @proceedings {491, title = {Use of the Short Wave Radio to prove the ionosphere with students from a public school in Brazil}, year = {2021}, month = {03/2021}, publisher = {HamSCI}, address = {Scranton, PA (Virtual)}, abstract = {

Knowledge of the characteristics of the ionosphere is largely based on its effects on electromagnetic waves. For the teaching of the atmosphere layers, in Brazil, as public schools have textbooks, pictures and videos, however, a practical experiment is not often performed . To remedy this gap, using low-cost materials, an experiment was carried out, well known for radio amateurs using two receivers, one portable shortwave (5.950 to 6.200 MHz and 7.100 to 7.300 MHz) and the other to FM (88 to 108 MHz), where shortwave radio stations with foreign language broadcasts were randomly tuned to characterize broadcasts from abroad. It was compared with some FM radio broadcasts from neighboring municipalities, previously researched on the internet and it is reckoned that it was not possible to receive these stations. There was a surprise from the students when they heard transmissions in other languages (from other distant countries) and did not listen to FM radio stations relatively close, thus proving the existence and application of the ionosphere during science classes.

}, url = {https://hamsci2021-uscranton.ipostersessions.com/?s=89-49-DB-01-08-CF-69-14-C0-96-58-9C-AB-F9-C9-A3}, author = {Alexandre Takio Kitagawa} }