nexus
Member
AO-51 (Amateur Orbiting Satellite Carrying Amateur Radio "OSCAR") is a very easy satellite to not only intercept comms from, but also to talk through if you have a ham license.
This satellite is basically a cross-band repeater using FM mode. The uplink frequency that earth stations transmit on is on 145.9200 mHz with a 67.0 hz PL tone. But for everyone who wants to listen to the satellite, we all need to tune our radios to the UHF downlink frequency of 435.3000 mHz FM, and no pl tones.
There are two basic things you need to know in order to listen in on this satellite.
1. You need to know your Long/Lat cordinates or your grid (grids are used by hams to determin a geographical area on earth's surface).
2. The location of the satellite and the time it will pass over your field of view.
If you don't know your LONG/LAT or grid square number, you can easily get that by going here: http://www.arrl.org/locate/locate.html
From that page you can enter in your city and state and it will give you both LONG/LAT and your grid square number. Then you will want to go to this site to get the list of passes for AO-51 to your location: http://www.amsat.org/amsat-new/tools/predict/
From there enter in your grid square into the box and click calculate and it'll automatically put yout long/lat in and then click pridict button. It will then show you the next 10 passes for your location. Keep in mind the time is listed in UTC (universial time cordinate) and that means you need to ADD 5 HOURS to your local time to get UTC. (example. if its 1400 hours your time, in UTC it will be 1900 hours)
Pick the time you want to go listen to it, and select the live tracking link to actually see the track of the satellite. As it is fixing to pass over you, go outside (if its a portable) and first tune 5khz ABOVE the center freq (435.3000) so you'll be on 435.3500 mhz as the bird gets above your location you'll need to be on center (435.3000 mhz) and as the bird is leaving from your location you'll want to tune DOWN 5khz to 435.2500 mhz.
The reason for this is the doppler shift effect. You should get a good 6 to 7 minutes of monitoring on each pass... Also if using a portable radio with a telescoping antenna or rubber duck, be sure and try to keep the antenna in a slight angle to the ground, say 35 degrees or so. If you hold it completely vertical it won't pick up the bird as strong. So holding it at an angle will give you best results. If you are using a mobile mounted antenna or a mast mounted antenna don't worry about it. Hams have been known to get into the AO-51 with a mobile. So it can be done. And I've personally intercepted hams talking through it using a rubber duck on my handheld.
Good luck and enjoy...
This satellite is basically a cross-band repeater using FM mode. The uplink frequency that earth stations transmit on is on 145.9200 mHz with a 67.0 hz PL tone. But for everyone who wants to listen to the satellite, we all need to tune our radios to the UHF downlink frequency of 435.3000 mHz FM, and no pl tones.
There are two basic things you need to know in order to listen in on this satellite.
1. You need to know your Long/Lat cordinates or your grid (grids are used by hams to determin a geographical area on earth's surface).
2. The location of the satellite and the time it will pass over your field of view.
If you don't know your LONG/LAT or grid square number, you can easily get that by going here: http://www.arrl.org/locate/locate.html
From that page you can enter in your city and state and it will give you both LONG/LAT and your grid square number. Then you will want to go to this site to get the list of passes for AO-51 to your location: http://www.amsat.org/amsat-new/tools/predict/
From there enter in your grid square into the box and click calculate and it'll automatically put yout long/lat in and then click pridict button. It will then show you the next 10 passes for your location. Keep in mind the time is listed in UTC (universial time cordinate) and that means you need to ADD 5 HOURS to your local time to get UTC. (example. if its 1400 hours your time, in UTC it will be 1900 hours)
Pick the time you want to go listen to it, and select the live tracking link to actually see the track of the satellite. As it is fixing to pass over you, go outside (if its a portable) and first tune 5khz ABOVE the center freq (435.3000) so you'll be on 435.3500 mhz as the bird gets above your location you'll need to be on center (435.3000 mhz) and as the bird is leaving from your location you'll want to tune DOWN 5khz to 435.2500 mhz.
The reason for this is the doppler shift effect. You should get a good 6 to 7 minutes of monitoring on each pass... Also if using a portable radio with a telescoping antenna or rubber duck, be sure and try to keep the antenna in a slight angle to the ground, say 35 degrees or so. If you hold it completely vertical it won't pick up the bird as strong. So holding it at an angle will give you best results. If you are using a mobile mounted antenna or a mast mounted antenna don't worry about it. Hams have been known to get into the AO-51 with a mobile. So it can be done. And I've personally intercepted hams talking through it using a rubber duck on my handheld.
Good luck and enjoy...
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