One of the research projects under development at the CRS' Van
Andel Creation Research Center is the use of amateur radio equipment
as a radio observatory to study the characteristics and origin
of meteors entering the earth's atmosphere. Meteor showers are
thought to be debris resulting from the breakup of comets, perhaps
less than 10,000 years ago. What is the rate and pattern of meteor
bombardment? Can any conclusion be drawn about the rate of accumulation
of meteoritic dust on the earth's surface? The
Stardust meteor observatory is currently collecting data on an
average of 3,000 meteor falls per day.
Stardust is a program
to evaluate incoming meteors by monitoring the VHF radio reflectivity
of ionized meteor trails. Meteor trails normally form from 90
miles up down to about 70 miles or so. These trails are composed
of ionized atmospheric gases. A typical trail may be 20 miles
in length, a few feet in diameter, and may last from 0.5 seconds
(or less) up to perhaps 30 seconds for a really bright "fireball."
The more energy imparted to the atmosphere, either be velocity
or by size, the longer the ionized trail will last. Incoming speeds
are between about 40,000 and 140,000miles per hour. Size is usually
that of a sand grain.
The ionized meteor trail has an interesting property. It will
cause reflection of radio signals in the 30 MHz to 150 MHz range.
Mid-range frequencies are best. An FM or TV receiver that is tuned
to a station far beyond the line of sight will occasionally detect
a momentary reflection of the sky wave signal back down to earth.
Depending on meteor activity, size and velocity of the meteor,
power of the transmitting station, distance of the transmitting
station, orientation and gain of the receiving antenna, sensitivity
of the receiver, etc., it is possible to detect 3,000 to 6,000
meteor trails in a 24 hour period. Though it is not possible to
tell precisely, we estimate that our system covers a "footprint"
about 300 miles wide and 800 miles in length.
Our system uses a computer controlled Icom PCR-1000 all band receiver
with the signal strength output being fed into a second computer
using a DATAQ A/D converter for display and recording. The accumulated
data are then analyzed with a custom software program.
In June 2000 we established a second Stardust observatory near
Sebring, Florida. This one is being operated by Bob Meyer. He
is a retired missionary who is an amateur radio operator and who
has a lot of technical background. In December 2000 a third Stardust
observatory was established at Cedarville College in Cedarville,
Ohio. This observatory will be used by the Electrical Engineering
department and will incorporate student and faculty research projects
to improve signal detection and analysis and to reduce interference
problems.
These three observatories have been established through generous
donations of friends and members who have earmarked contributions
to this specific project. That support is greatly appreciated.
Continuing support for this project will allow us to continue
its development
Implications of this project relate to evaluating decaying comets
that produce meteor showers, developing a data base on meteor
activity to evaluate accumulation of meteorite dust coming into
the atmosphere, developing a model for the origin and age of meteorites,
and basic meteor astronomy.
While we have put much time and many dollars into the development
of this project, a meteor observatory station can now be replicated
by anyone who has two dedicated computers, about $1,500 and the
ability to build electronic equipment from plans and instructions.
Standard test bench equipment would also be needed. The computers
do not need to be high speed but must run Windows. A high degree
of curiosity is also an essential element!
If you would like to visit any of these locations, please let
me know and I will try to make arrangements. We would be glad
to work with other members who might have an interest in building
the Stardust system. It is a fascinating project and it is quite
impressive to see signals on the computer screen that are generated
by visitors from outer space!
Project Details:
STARDUST RADIO-METEOR
OBSERVATORY DATA FOR JANUARY, 2000 Observers, Del Dobberpuhl,
John Meyer, Jack Meyer.
Location: Van Andel
Creation Research Center, Chino Valley, AZ. USA. 34 50 ' 50"
N, 112 29' 50" W. Elevation 1347 meters ( 4420 feet) above
sea level.
Frequencies: 88.5,
88.9, and 89.7 MHz for signal FM receivers; 87.9 MHz (currently
an unused frequency) for noise FM receiver.
Transmitter Locations:
Many possibilities including: El Paso, TX ; Mesquite, TX: Commerce,
TX; Abilene, TX; Farmington, NM; Colorado Springs, CO.
Antenna: Dipole housed
in corner reflector built from wire screen. Open end of reflector
tilted at about 65 degrees above horizon and facing due east.
Antenna Pre-amplifier:
27 db gain.
Coax Cable: 152 meters(500
feet) of RG-8
Receiver Inputs: Four-way
splitter with outputs to each receiver
Receivers: Four OPTIMUS
STA-80 FM receivers modified to 10KHz band width using IF amplifiers
with 80 db dynamic range signal strength output voltages.
Data Acquisition:
DATAQ type DI-190, 2-channel module connected to computer serial
input port. Acquisition rate is forty samples per second for each
channel. Channel one is the combined peak signal amplitudes from
the three signal receivers. Channel 2 is the signal amplitude
from the noise receiver. Data are reported only when signal strength
at the antenna exceeds -124 dbm. Storage continues for one second
after signal drops below -124 dbm.
Interference Rejection:
Data storage is inhibited if interference at the noise receiver's
frequency exceeds -122 dbm at the antenna. Inhibiting continues
for one second after noise level drops back below -122 dbm.
Data Reduction: Mostly
automated computerized reduction.
Data Format: Results
are shown as total seconds of reflection time per hour. When no
figure is shown, the equipment was either out of service or results
could have been contaminated by sporadic-e or interference.
Meteor Data File (January 2000)
The
VACRC is looking for electronics technicians, amateur radio operators,
and communications engineers to assist in the project on a voluntary
basis. Those interested should contact the VACRC at the address
or email listed below.
