IMPROVING THE VARIOUS PROPERTIES OF THE UDA-YAGI ANTENNA

Рассматривается антенна Уда-Яги, которая предназначена для приема сигнала наземного телевещания в 57 частотном канале. Самыми важными характеристиками для антенны Уда-Яги являются коэффициент направленного действия, передне-заднее отношение (коэффициент защитного действия), при этом данные характеристики сильно зависят от числа директоров, применяемых в конструкции антенны. На основе произведенного электродинамического моделирования было определено, как изменятся характеристики диаграмм направленности антенны на частоте 762 МГц при применении различного числа директоров - от 1 (3-элементная антенна Уда-Яги) до 12 (14-элементная антенна Уда-Яги), при этом определено оптимальное количество директоров для ситуации, когда требуется достижение максимальной помехозащищенности (максимальное значение передне-заднего отношения). Приводятся диаграммы направленности при различном числе директоров на частоте 762 МГц, графики коэффициентов защитного действия (ПЗО) от числа директоров и от частоты, таблицы со сравнительными характеристиками диаграмм направленности. Моделирование производилось с использованием метода моментов, так как при его применении достигаются высокая скорость расчетов, а также высокая точность результатов. При моделировании антенна имела один рефлектор и активный элемент в виде полуволнового диполя The article considers the Uda-Yagi antenna, which is designed to receive a terrestrial television signal in a 57-frequency channel. The most important characteristics for an Uda-Yagi antenna are directivity, front-to-back ratio, and these characteristics are highly dependent on the number of directors used in the antenna design. On the basis of the electrodynamic simulation, we determined how the characteristics of the antenna directivity patterns at a frequency of 762 MHz will change when using a different number of directors - from 1 (3-element Uda-Yagi antenna) to 12 (14-element Uda-Yagi antenna), at the same time, we determined the optimal number of directors for the situation when the achievement of maximum noise immunity is required (the maximum value of the front-to-back ratio). The article gives directivity patterns for different numbers of directors at a frequency of 762 MHz, dependencies of directivity coefficients on the number of directors and on the frequency, tables with comparative characteristics of directivity patterns. We carried out the simulation using the method of moments, since it achieves a high speed of calculations, as well as high accuracy of results. During simulation, the antenna had one reflector and an active element in the form of a half-wave dipole

Determination of DVB-T2 Signal Quality in Nigeria: A Case Study of Jos, Plateau State, Nigeria

This study presents the evaluation of digital video broadcasting-terrestrial second generation (DVB-T2) Television signal quality in Jos using Integrated Television Services Limited signal. The delivery of quality Television signal remains problematic in Nigeria due to signal attenuation and degradation between the transmitter and receiver station. This is primarily due to environmental and atmospheric perturbations prevalent along the signal paths. This research aim is to determine the signal quality of DVB-T2 Television system in Jos, Plateau State. The simple field measurement methodology was adopted in measuring field strength and channel power parameters. These measurement parameters were used to calculate for carrier-to-noise ratio (CNR) and signal-to-noise ratio (SNR) through empirical method. Finally, CNR and SNR were used to determine the signal quality of DVB-T2 signal in Jos. The result of the research shows that DVB-T2 signal in the primary service areas has good and reliable signal apart from the rocky environments.

Impact of C-SPAN on US Democracy

In 1979, a new US cable television network was created. It was called C-SPAN, an acronym reflecting its origin. The Cable Satellite Public Affairs Network was created to record public affairs programming and deliver it by cable and satellite into US homes. Cable was a nascent industry at that time. It began mostly as a retransmission of broadcast signals into areas that had poor terrestrial reception. The satellite revolution of the 1970s known as “Open Skies” made it possible for new networks to deliver their signals to home satellite dishes, but more importantly, to cable operators who were offered new exclusive, nonbroadcast networks that they could sell to the local subscribers. Home Box Office, or HBO, was successful delivering movies this way, which allowed commercial-free content offered for a premium. Cable operators were thus interested in this new satellite-delivered content that would distinguish cable and give customers reasons to subscribe. Brian Lamb was one of these network entrepreneurs, who with a background in radio, broadcast television, public affairs, satellite policy, and cable television, envisioned a cable satellite network that would bring unedited, Washington, DC–based public affairs programming delivered over cable television systems to American homes. He convinced some cable television executives, with a complementary entrepreneur spirit, to invest in his idea. The result was a nonprofit network dedicated to public affairs events in their entirety. It would be paid for by monthly, per-home license fees paid by the cable operators to the network in exchange for receiving the television signal. This, however, was just half of the story of the origin of C-SPAN. While Brian Lamb was developing his idea and thinking of how content from Washington, DC, events could be delivered via satellite to cable systems, another group was also working on a similar idea. The year was 1977 and the group was the United States House of Representatives. The mid-1970s were a heady time for the US Congress. President Nixon resigned in 1974 after congressional investigations of the 1972 Watergate break in. Congress passed the far-reaching War Powers Act and Congressional Budget Impoundment Act over presidential vetoes to strengthen Congress over what noted historian Arthur Schlesinger Jr. wrote was the “Imperial Presidency.” When the US House of Representatives first televised its proceedings on 19 March 1979, C-SPAN began transmitting the signal via satellite and the new network was available.

Iterative Algorithm Offset and Angle Rotation Estimation with Additive and Multiplicative Noise for Space-Time Superposition of Television Signals

The estimation of displacements, rotation angle and other deformation of images is an urgent problem in the intelligence video recording system. One of the main tasks in assessing image deformations is to increase the speed of data processing. Significant amounts of information contained in a television signal limit the possibilities of using brute force methods, which are a universal solution for estimating unknown parameters. The paper considers the problem of estimating the displacement and angle of rotation under the influence of additive and multiplicative interference for the spatial-temporal alignment of television signals. Reducing the processing time is carried out through the use of an iterative procedure for estimating parameters by successive approximation with separate estimation of the angle of rotation and displacement.

Determining the Context of Television Serial Drama Viewership in Nairobi, Kenya.

The study sought to determine the context of television serial drama fiction viewership in Nairobi, Kenya. Watching of television serial drama fiction/soap operas is popular among Nairobi audiences. The research is anchored on uses and gratification and cultural proximity theories. The study employed a mixed-method design approach and used simple random, purposive and systematic sampling techniques to determine the population sizes. The study is further organised at two levels. In the first phase, 422 interview guide questionnaires were administered to respondents in households in three randomly selected constituencies of Nairobi followed by nine FGDs. The constituencies were Embakasi West, Makadara and Kibra. The survey questionnaires were finally analysed by SPSS and triangulated together with the qualitative findings. There is an emerging digital divide in the context of television viewership due to the impact of digital technology. The study found that many of the audiences now pay to access the television signals which they perceive as a gain reversal. Thus, the 'free' television signal connection has acquired a different meaning where private institutions, as opposed to the public (a government body), are now in charge of signal distribution and charge a monthly fee for access. From the recommendation, the government should make digital TV accessible by zero-rating taxes to the distributors. In addition to that, they should come up with a policy change that the first four most popular FTA TV stations should be accessible to the audiences at all times even when other channels are switched off.