ABMO Radio Page
Latest radio meteor echoes from W Kelowna, B.C.
Highest none shower counts are at local sunrise and the lowest are at sunset.
The observatory is located in West Kelowna and it uses the forward scatter technique of meteor echo detection. The receiver is tuned to TV channel 4’s video carrier frequency (negative offset) at 64.240 MHz. The echoes are from the video carriers of the two station listed below:
|Moose Jaw, SK
When a meteor has the proper geometry between the transmitting TV station and the receiving station an echo is produced as the receiver as the signal is reflected off the ionized plasma produce while the meteor ablates in the earth’s upper atmosphere. The ionization usually occurs between 110 down to 60 km up, thus giving a radio coverage out to about 1400 km radius of the receiver.
The station consist of an Icom PCR-1000 to a seven element log periodic antenna. The antenna is installed in the attic and pointing 70 degrees or towards the northeast. A fifty foot piece of RG-58 coax connects the antenna to the receiver. No pre-amps are used. The PCR-1000 is a software controlled receiver; a small black box with only an on and off switch on the front.
In the back of the PCR-1000 are:
BNC Antenna connector, a ground post, DC Input, Audio Out, a RS-238 connector for communication with the computer, and a special 9600 bps audio filtering bypass for high speed digital packet radio used on amateur built satellites (AMSAT).
During the major showers the observatory employs several different programs on several different computers on the LAN. Audio is split off the PCR-1000 as seen above (Y-adapter audio out) and shared among the computers during the showers. Alternatively, I use a second receiver, the ICOM R-8500 that runs in parallel with the PCR-1000 but on a different frequency, and run the audio from it to separate computer for real time analysis.
If a shower is predicted to show once in a lifetime activity I will also run an ICOM IC-746 transceiver. I usually devote the IC-746 to listening to 40.530 MHz, the US SNOTEL meteor system. SNOTEL has two master stations (transmitters) located in Utah and in Idaho which put in strong meteor burst signals into BC.
The software does the actual detection, counting, data filing and display work. Software in use includes Spectrum Lab, mAnalyzer, HROfft, all capable Windows programs. Watch for a software discussion in the Radio Detection Basics in the Radio Methods section of the site. In addition to the above programs the observatory runs Janalyzer and a self written code. Which program is used is dependent on the subject understudy or nature of the shower.
Note: I do run the above programs on both Windows XP and on Linux machines. To see how I run it on a Linux machine please go to the RMOB site and read the article. Janalyzer is written in Java so is cross platform ready.
I set my software to output data at ten minute periods and on the hour. Depending on what software is running, duration for each 10 minute and hourly interval is recorded along with signal strengths in several bins of approximately 10 dB, 20 dB, 30 dB, and greater than 30 dB. Total time in seconds per period for each power level is also recorded.
A FFT spectrogram for each five minute period is ftp to an external site as well as saved on a local hard drive for study later or for the correlation with video fireballs
To be continued…