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In Depth Satellite Calculations
The following calculations were made by utilizing Orbitron and Microsoft Excel.
AO-51’s Downlink S/N for an isotropic (0 dB gain) antenna at the earth station.
AO-51’s Downlink S/N for an isotropic (0 dB gain) antenna at the earth station.
Same as above, but zoomed in from 0 degrees to 30 degrees.
A comparison of AO-51, SO-50, and AO-27.
Transmit Power of each of the Satellites are :
·
AO-27 = 500 milliwatts ( 27 dBm)
·
AO-51 = 500 milliwatts ( 27 dBm)
·
SO-50 = 250 milliwatts ( 24 dBm)
The assumption for the earth station receive antenna is isotropic
(0 dB gain).
A comparison of the Duration of the Pass for AO-51
The difference is the minimum receivable elevation.
To get you elevation lower, you will need to utilize a higher gain
antenna.
So for the same pass, you duration is longer if you can hear the
satellite lower in the sky.
A comparison of AO-51s downlink S/N vs. the uplink S/N.
The assumption below is that the uplink is transmitting 1 watt (30
dBm) of power with an isotropic antenna.
You can see, that uplink is usually not the problem.
A comparison of AO-51s downlink S/N vs. the uplink S/N.
This is the same graph as above, but I included several different
transmit powers with an isotropic antenna.
·
1 Watt (30 dBm) – same as above
·
2.5 Watts (34 dBm) – an HT on highpower
·
10 Watts (40 dBm) – a mobile at low power
·
50 Watts (47 dBm) – a mobile radio
Once you add a antenna with gain, you are in like gang busters!
You can see, that uplink is usually not the problem.
