Very useful data for those interested in Meteor Scatter Propagation
See URL of Meteor Information Website at the end !
The following data applies to the radio detection of ANY METEOR ENTERING THE EARTH'S UPPER ATMOSPHERE
Note that data for visual observation should only be used as a rough guideline since radio detection and visual detection will peak at different times.
This occurs because visual observation is a 2-point system, i.e. only the meteor (source of light energy) and the observer are involved.
Radio detection is a 3-point system, i.e. the source of energy is a radio transmitter, the meteor (ionized trail) is merely a 'reflector,' and then there is the observer. The geometry involved in radio detection is therefore more complex than that in visual detection. Consequently, meteor position is more critical in radio detection than it is in visual detection.
The data below indicates which direction to point a beam antenna (yagi, tv antenna, etc.). If you use a dipole, it should be strung perpendicular to the directions given below. For example, if the best signals come from the North, then a beam antenna should be pointed North, but a dipole should be strung East-West. Data shows the best times and directions for longitudes of 60, 75, 90, 105 and 120 deg. In North America, latitude will change the times only slightly. Since you should accept the times for what they are (mathematical calulations which are not necessarily extremely precise), the variation due to latitude becomes insignificant. Having said that the calculations are not extremely precise, you should listen several hours before and after the times listed to ensure that you don't miss the peak. To accomplish this (and avoid losing too much sleep or work time) you might try feeding the audio output from your receiver into the audio input of a VCR. This will give you 6 hours of tape. You can playback the tape through your tv set later. If you set the VCR timer for 3 hours before the times indicated below (in which case the tape will run until 3 hours after the times indicated), this should increase your chances of success. Also note that I have given times for North, South, Northeast and Northwest propagation. Since 'reflection' from meteors should be symmetrical, this would indicate that reception from the Southwest and Southeast should be possible. In fact, this should be true, however, Northeast and Northwest are better bets for Leonids. That doesn't mean you should not give Southwest and Southeast a try. As you will figure out when you see the data, the times for North and South propagation are the same; therefore you can use the data for Northeast propagation if you want to listen for signals from the Southwest and data for Northwest propagation if you want to listen for signals from the Southeast. I calculated times for 45 deg North and also 30 deg North. At 30 deg North, most propagation is North-South, there is less of a chance for hearing signals from other directions than there is at 45 deg North. Again, that should not stop you trying other directions if you live in the south. One last point--the times below are peak times. Signals will be heard before and after these times.
The data was derived from a program written by Michael Owen, W9IP. All times are UTC.
Receiving site location: 60 deg W Direction and times to listen-- North: 0700 and 1345 UTC Northeast: 0730 South: 0700 and 1400 Northwest: 1300
Receiving site location: 75 deg W Direction and times to listen--N: 0800 and 1500 NE: 0830 S: 0800 and 1445 NW: 1400
Receiving site location: 90 deg W Direction and times to listen--N: 0900 and 1600 NE: 0930 S: 0900 and 1545 NW: 1500
Receiving site location: 105 deg W Direction and times to listen--N: 1000 and 1700 NE: 1030 S: 1000 and 1645 NW: 1600
Receiving site location: 120 deg W Direction and times to listen--N: 1100 and 1800 NE: 1130 S: 1100 and 1800 NW: 1700
For further background information--Sky & Telescope, December 1997, p. 108; Observer's Handbook (Royal Astronomical Society of Canada), 1998 edition, p. 183 or 1999 edition, p.205; or Philip Gebhardt, VE3ACK pgebhardt@compuserve.com Greenbank, Ontario, Canada
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Havana, Cuba
16 November, 1998
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