A Study of the End Point Path Geometry in Meteor Burst Systems Using a Microcomputer Signal Logger.
Abstract
Available from UMI in association with The British Library. Radio propagation experiments generally need large amounts of data to be gathered over extended periods. This thesis describes the design of a signal logger for unattended gathering of signal statistics from a meteor burst radio path, using two receiving antennas. Using a VHF broadcast radio station as a signal source, the data logger was used to investigate the properties of signals received with one antenna directed at the path mid point and a second at the receiving station zenith (end point). Calculations of path loss at 70 and 50 MHz showed that the mid point path loss should be lower than the end point path loss by up to 3dB for ranges up to about 900km but higher above this range. Calculations for the 70MHz 1173km experimental path showed that the path loss for end point illumination should be in the order of 1dB less than that for mid point. Results suggested a larger percentage of large amplitude signals on the end point antenna, but the mean end point path loss in the order of 1dB greater than mid point. Burst durations were found to be lower on end point but not to the extent predicted by theory. The sampling rate of the data logger was initially thought to be the main contributory factor to this effect, but further experiments showed that this was not the case. Duty cycle of the two path geometries was also compared, and a computer model written, predicting a 4:1 advantage for mid point. Results confirmed the model, showing the advantage varying from 1.14 to 6.36 with a mean value of 4.0. This ratio shows a small reduction during periods of high shower activity. In conclusion, the data logger has been proven, its limitations discussed, and the limitations and advantages of end point illumination investigated.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- 1990
- Bibcode:
- 1990PhDT.........6W
- Keywords:
-
- Physics: Astronomy and Astrophysics, Engineering: Electronics and Electrical;
- Microcomputers;
- Packet Transmission;
- Packets (Communication);
- Radio Signals;
- Radio Transmission;
- Signal Fading;
- Very High Frequencies;
- Broadcasting;
- Computerized Simulation;
- Predictions;
- Sampling;
- Zenith;
- Astronomy