The Radio Meteor Project: Detect Meteors by Radio?
Detect Meteors by Radio?
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Even prior to the creation of the all-sky camera system, a radio meteor detection system was envisioned. Early plans called for making audio captures of
passing meteors that would sync with the video images. A lack of a suitable radio receiver hampered this approach. A few experiments utilizing a standard
FM radio receiver failed to obtain any useful results due to an inability to resolve fine-tuning issues. For the past year, attention to the topic waned as
the all-sky camera project took center stage.
Recently the SpaceWeather web site had a link to a NASA page which described a forward scatter meteor detection system. This detection system uses the reflection of a television carrier signal, not local to the receiver. The theory of operation is simple, yet elegant. Television reception is a "line of sight" proposition. This means that in practical terms, a ground-based antenna cannot receive signals from a transmitter more than 300 km away. When a meteor enters the atmosphere approximately 100 km up, it creates an ion trail that is within the line-of-sight of the transmitter. |
The trail is also reflective to certain types of radio signals. That reflected
signal is now briefly detectable to a distant receiver.
The choice of television signals is not random. TV signals have a relatively high power output and the commonly used frequencies are short range. Additionally, they are not generally reflected by atmospheric effects. The NASA page, details a system which uses a channel 4 (67.25 MHz) as the target frequency and a relatively advanced computer-based, radio receiver IC- PCR1000. The antenna used in the system appeared to be an easily constructed, 2-element yaggi. The site also claimed to provide free software for visual monitoring of the meteor trail reflections or echoes. A lack of a radio receiver in the right frequency range and a lack of consensus on the best frequency to monitor caused the project to be shelved. However, the meteor detection program was immediately reenergized when NJAA club member, Jim Roselli, donated the necessary IC-PCR1500 receiver. |
IC-PCR1500 receiver
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The NJAA operates on leased premises administered by The State of New Jersey, Department of Environmental Protection, Division of Parks and Forestry