Timeline for How is a space probe's antenna directed toward Earth?
Current License: CC BY-SA 3.0
10 events
| when toggle format | what | by | license | comment | |
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| Jul 12, 2015 at 19:40 | history | tweeted | twitter.com/#!/StackSpaceExp/status/620316862308614144 | ||
| Jul 11, 2015 at 16:09 | vote | accept | Zoran | ||
| Jul 11, 2015 at 15:52 | answer | added | Mark Adler | timeline score: 7 | |
| Jul 11, 2015 at 14:26 | history | edited | kim holder |
edited tags
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| Jul 11, 2015 at 12:36 | comment | added | user | Also, the beam width isn't a binary on/off either, but a gradual reduction of signal strength. You pick a value, say, -30 dB to peak power, and calculate the specific antenna's beam width at the specific intended frequency to that power ratio, then state that as the transmission beam width. If you are slightly outside of that, you might receive at -32 dB to peak power, whereas if you are slightly inside of it, the value might be -28 dB. | |
| Jul 11, 2015 at 12:32 | history | edited | user | CC BY-SA 3.0 |
Better title
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| Jul 11, 2015 at 12:28 | comment | added | user | The emission beamwidth is also a specific angle (dependent on the relationship between antenna size and transmission frequency or wavelength). For large antennas and high frequencies (upper UHF and higher, which is what the DSN uses) this can quite easily become fractions of a degree, but over tens of AU, that's still quite a lot of margin. You'll want to maintain as good a lock as possible to maximize the useful signal strength received, but it's not a total disaster if you are slightly off: the mission's radio link budget is going to have to include some margin for error and variance anyway. | |
| Jul 11, 2015 at 8:50 | comment | added | Hobbes | Related question (about the antenna position of the receiver on Earth): space.stackexchange.com/questions/9803/… | |
| Jul 11, 2015 at 7:33 | review | First posts | |||
| Jul 11, 2015 at 7:40 | |||||
| Jul 11, 2015 at 7:29 | history | asked | Zoran | CC BY-SA 3.0 |