DETECTION OF METEORS BY RADIO SCATTER TECHNIQUES

by John Nordlie

Proposal for research project to Dr. Charles Wood,
University of North Dakota, Space Studies Dept.
PROBLEM:
Astronomers have studied meteors for many years. To determine the source of a certain group of meteors, it is necessary to gather data on the time the meteors fell, the size, shape, speed, color, and origin in the sky of the shower. In the past, the only way to gather such data was to visually observe the meteors while they fell through the atmosphere. While the data from visual observation is quite useful, there are many factors which can prevent these observations from being done. Observations could only be done during night time hours, away from city lights, and only on cloudless nights. A way to gather data on meteors during all kinds of weather and all hours of the day would therefore be highly useful.

OBJECTIVES:
The objective of my research is to build an automatic instrument which would record meteors 24 hours a day, in all kinds of weather. The system will use a phenomenon called "meteor scatter", which is the reflection of radio waves by the ionized trails left by meteors streaking through the atmosphere. Ham radio operators have used this method for years to communicate with each other over distances normally too great for radio waves to reach. The system will consist of a directional gain antenna (i. e. Yagi) pointed at a radio transmitter normally out of range. The antenna will be connected to a suitable receiver, which in turn is connected to a micro computer in such a way that the computer could measure the strength of the signal being received. In operation, the signal would be too low to be detected, but a meteor event would allow radio waves from the distant station to be reflected down to the antenna, and thus be recorded by the computer.

METHODOLOGY:
Two ways of implementing such a system would be (1) use a transmitter/receiver/computer system, or (2) use a commercial radio station's transmitter, and only set up the receiver/computer system. The first method has the advantages of selecting a convenient frequency and transmitter-receiver distance, while the disadvantages are cost and finding an unused frequency. The second method has the advantage of having a wide range of commercial equipment to choose from, while the disadvantage is the crowding of commercial radio bands in many areas makes it difficult to find a spot on the band free of local interference.

WHY THIS PROJECT IS IMPORTANT:
Using visual observation techniques, data gathering on meteors can occur ideally only 12 hours per day, so half of the possible data on meteors cannot be gathered. Using the radio scatter technique, data can be gathered 24 hours a day, in all kinds of weather. An added bonus is that the instrument is totally automated, so observer fatigue is not an issue. Data gathered on meteor activity is paramount to the detection of new meteor streams and their orbits, so more data gathered makes better determination possible.

WHAT I EXPECT TO LEARN:
I expect to learn more about meteors and their orbits and sources. I also expect to learn more about radio propagation and signal processing. It may be desirable to set up many such receiving stations all over the country to gather more data and to verify location and patterns in meteor events. This study will help me determine if this plan is possible or desirable.


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