Title :
Point to point communication at VHF in India
Author_Institution :
Div. of Radio & Astrophys. Sci., Nat. Phys. Lab., New Delhi, India
Abstract :
A high percentage of anomalous long distance TV signals at Delhi was observed on channel 2 (47-54 MHz) as compared to other channels of Band I (47-68 MHz) and Band III (174-230 MHz), when monitored between early morning and midnight during a solar cycle (1986-97). Various ionospheric modes of propagation have been identified for Band I. These propagation modes are sporadic-E layer during summer day time, normal F-region around equatorial anomaly belt, spread-F phenomenon during night and ionospheric modification in the form artificial spread-F due to heating by high power shortwave broadcast transmitters at the control points. Such modes are strong enough to reflect communication signals at frequencies between 20 to 60 MHz and hence can help in realizing an effective low cost long distance communication link in India
Keywords :
VHF radio propagation; ionospheric electromagnetic wave propagation; radio links; sporadic-E layer; television reception; 174 to 230 MHz; 47 to 68 MHz; Delhi; India; VHF; anomalous long distance TV signals; equatorial anomaly belt; ionospheric propagation modes; low cost long distance communication link; normal F-region; point to point communication; sporadic-E layer; spread-F phenomenon; Belts; Broadcasting; Communication system control; Costs; Frequency; Heating; Monitoring; TV; Temperature control; Transmitters;
Conference_Titel :
TENCON '98. 1998 IEEE Region 10 International Conference on Global Connectivity in Energy, Computer, Communication and Control
Conference_Location :
New Delhi
Print_ISBN :
0-7803-4886-9
DOI :
10.1109/TENCON.1998.798165
