48 research outputs found
Bit error rate for private mobile radio (PMR) due to lightning electromagnetic field radiation (LEMR)
The conceptual implementation to access the extend influence of lightning electromagnetic radiation (LEMR) on mobile radio communication. Binary data has been transmitted through a pair of Motorola Talkabout T5420 walkie-talkie with 14 channels and 38 eliminator codes and operates on 14 UHF Family Radio Service (FRS) Frequencies. Two types of induced interferences which are high voltage and high current experiment has been conducted in High Voltage Laboratory, Institute of High Voltage and High Current, UTM. In order to achieve the implementation mention above, a research has been conducted with the title of the project is 芒鈧揃it Error Rate for Private Mobile Radio (PMR) Due to Lightning Electromagnetic Field Radiation (LEMP)芒鈧拷. The objective of the first part of the research is to determine whether the lightning could produce the error of the bit in term of bit error rate in digital communication. If there any errors, the research will continue to ascertain how much it damage or influence the data. In optical communication, in practice, a low bit error rate in the region 10-7 to 10-10 may be tolerated with pulse code modulation (PCM) transmission. Although, in wireless communication, the receiver will face much higher bit error rate due to the environment and nature phenomena such as rain drops, fogs, thunderstorm and lightning
Narrow Bipolar Pulses and Associated Microwave Radiation
Narrow Bipolar Pulses (NBPs) is a special type of intra-cloud lightning discharge activities. It is known with other names also such as Narrow Bipolar Events (NBEs), energetic intracloud events, and Compact Intracloud Discharges (CIDs). NBP signatures have been measured by using various methods such as broadband antenna systems, HF-VHF direct measurement systems (filter-detector receiver), and satellite- based systems. To the best of our knowledge, there are no attempts have been made to measure NBP signatures at microwave region so far. In this paper, observations of microwave radiation from thunderstorms have been made during the northeast monsoon season of 2012 in Malaysia. Broadband fast antenna system and wideband microwave receiver captured simultaneous records of NBPs electric field change and microwave radiation, respectively. The wideband microwave receiver consisted a Low Noise Amplifier (LNA) connected to a Band Pass Filter (BPF) with operating frequencies between 1.5 and 3 GHz. Electrical signals induced by the incident electric fields on a whip antenna with omni directional pattern (E-plane half power beam width 19 degrees and 9 dBi gain) were directed towards the LNA by using a 5 meters 50惟 RG58 coaxial cable. The output electrical signals of the BPF were digitized directly by an oscilloscope at a rate of 2.5 Giga Samples/second. An oscilloscope at a rate of 25 Mega Samples/second digitized the output of electrical signals from the broadband fast antenna system. Strong noise-like burst of microwave radiation pulses associated with NBP events were detected. The total duration of the microwave bursts of the pulses is in the range between 5 and 8 渭s meanwhile the total duration of the NBP pulses is in the range between 10 to 25 渭s. We will provide detail time- frequency analysis of both NBP and its associated microwave radiation by using wavelet transform method
Wavelet Analysis of The First Pulse of Initial Breakdown Process in Lightning Discharges
The investigation is done using wavelet transformation in order to seek for differences in the initial breakdown process between negative cloud-to-ground flash (CG), positive CG, cloud flash (IC), and isolated breakdown (IB) process. A total of 66 waveforms were selected from the collection of 885 waveforms collected during summer thunderstorm between May and August 2010 at the premise of Uppsala University, Uppsala, Sweden. The recording unit consisted of a flat plate fast electric field broadband antenna measuring system with the sampling rate set to 20 Megasamples per second. The analysis was conducted only on the first pulse for each lightning events and the output from the wavelet transformation is shown as normalized power spectrum plotted in time-frequency domain as shown in Figure 1 below. The first pulses in negative CG are found to radiate intensely in average frequency range between 186 and 1637 kHz. The energy radiated by the first pulses of positive CG mainly concentrated in the average frequency range between 57 and 599 kHz. As for the cloud flash, the first pulses found to be spread out in the average frequency range between 398 and 3656 kHz and for isolated breakdown, the energy spread out between 44 and 279 kHz. The positive CG and IB flashes are tending to radiate at lower frequencies range within smaller range when compared to negative CG and IC. IB has the smallest average frequency range at 235 kHz while the average frequency range of IC and negative CG are more than 10 times and 6 times larger than IB, respectively. It can be speculated that the initial breakdown process of positive CG and IB flashes are most likely initiated from the same discharge process in the thundercloud. On the other hand, the initial breakdown process of negative CG and IC are most likely initiated from different discharge processes
The Estimation of Power Flux of Microwave Radiation from a Negative Narrow Bipolar Pulse at Low Earth Orbit Satellite Altitude
In this paper, we estimate power flux densities at two points in space within the orbiting range of low Earth orbit (LEO) satellite. One point located 200 km away from the narrow bipolar pulse (NBP) emission source with angle 胃 = 45掳 and the other point located 2000 km away from the NBP emission source with angle 胃 = 45掳. The sensitivity of the LEO satellite sensor must be larger than 10-8 W/m2/Hz at distance 200 km and 10-10 W/m2/Hz at distance 2000 km in order to be able to capture microwave radiation from NBP.
The Estimation of Power Flux of Microwave Radiation From a Negative Narrow Bipolar Pulse at Low Earth Orbit Satellite Altitude
In this paper, we estimate power flux densities at two points in space within the orbiting range of low Earth orbit (LEO) satellite. One point located 200 km away from the narrow bipolar pulse (NBP) emission source with angle 胃 = 45掳 and the other point located 2000 km away from the NBP emission source with angle 胃 = 45掳. The sensitivity of the LEO satellite sensor must be larger than 10-8 W/m2/Hz at distance 200 km and 10-10 W/m2/Hz at distance 2000 km in order to be able to capture microwave radiation from NBP
Distinctive features of radiation pulses in the very first moment of lightning events
This paper investigates the existence of distinctive features between 4 different types of lightning discharges, namely negative cloud to ground discharge (鈭扖G), positive cloud to ground discharge (+CG), cloud discharge (IC) and isolated breakdown discharge (IB). A total of 110 very fine structure waveforms of 44 鈭扖G, 16 +CG, 39 IC, and 11 IB discharges have been selected from a collection of 885 waveforms measured using fast electric field broadband antenna system. The measurements were carried out in Uppsala, Sweden from May to August 2010. We found that there are significant distinctions within the first 1 ms among different types of lightning discharges (鈭扖G, +CG, IC, and IB). For example, the pulses in 鈭扖G discharges are more frequent than other discharges; the pulses in +CG discharges have the highest intensity and the IC discharge pulses tend to have shorter duration
Lightning Interference in Multiple Antennas Wireless Communication Systems
This paper analyzes the interference of lightning flashes with multiple antennas wireless communication systems operating in the microwave band at 2.4 GHz and 5.2 GHz. A bit error rate (BER) measurement method was used to evaluate BER and packet error rate (PER) during 5 heavy thunderstorms on January 25 and March 17 to 20, 2011, respectively. In addition, BER measurements also were done on January 21 and March 30, 2011 under fair weather (FW) conditions providing a baseline for comparison. The Transmitter-Receiver separation was fixed at 10 meter with line-of- sight (LOS) consideration. We infer that lightning interfered with the transmitted digital pulses which resulted in a higher recorded BER. The maximum recorded BER was 9.9路10-1 and the average recorded BER and PER were 2.07路10-2 and 2.44路10-2 respectively during the thunderstorms with the average fair weather BER and PER values under the influence of adjacent channel interference (ACI) and co-channel interference (CCI) being 1.75路10-5 and 7.35路10-6 respectively. We conclude that multiple antennas wireless communication systems operating at the microwave frequency can be significantly interfered by lightning
Interference from cloud-to-ground and cloud flashes in wireless communication system
In this study, cloud-to-ground (CG) flash and cloud (IC) flash events that interfere with the transmission of bits in wireless communication system operating at 2.4 GHz were analyzed. Bit error rate (BER) and consecutive lost datagram (CLD) measurement methods were used to evaluate BER and burst error from 3 tropical thunderstorms on November 27, 28, and 29 during 2012 northeastern monsoon in Malaysia. A total of 850 waveforms from the electric field change recording system were recorded and examined. Out of these, 94 waveforms of very fine structure were selected which matched perfectly with the timing information of the recorded BER. We found that both CG and IC interfered significantly with the transmission of bits in wireless communication system. The interference level becomes worst as the number of return strokes (RSs) increases and the intensity of the flash intensifies. Narrow bipolar pulses (NBP) event is suggested to radiate the most intense microwave radiation pulses, larger than preliminary breakdown process (PBP) and typical IC flash and caused more severe burst error to wireless communication system. In CG flash, PBP event is suggested to radiate the most intense microwave radiation pulses that interfered with the bits transmission and caused significant burst error. RSs are suggested to radiate less intense microwave radiation but still interfere with the bits transmission and cause significant burst error especially when the number of RSs becomes larger. Furthermore, we found that the typical IC pulses interfered the bits transmission in the same way as PBP in CG flash and produced comparable amount of burst error
Analysis of Lightning-induced Transient in 2.4 GHz Wireless Communication System
This paper analyzes the effects of transient from lightning channel to wireless communication system operating in microwave band at 2.4 GHz. Received Signal Strength Indicator (RSSI) measurement method has been used to capture 3 lightning flashes (naked eyes method) with 7 spikes recorded at r distance from the lightning channel base with fixed d Transmitter- Receiver (T-R) separation at 1 meter. The transient effects have been evaluated in terms of Electric Field Strength, Signal-to- Interference-Noise Ratio (SINR), Bit Error Rate (BER) and Packet Error Rate (PER). During the first lightning flash event, more than 50% of total transmitted packets were corrupted for at least 3 seconds duration. The same happens during the second and third lightning flash events with more than 40% and 15% packets corrupted for durations of 3 and 2 seconds respectively. Interestingly the most suffered traffic types are video and speech signal transmission while data transmission is not affected at all