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Doppler and Radio.
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Mike Therrien Send message Joined: 12 Aug 09 Posts: 1 Credit: 76,177 RAC: 0 |
I get why your looking for doppler shifts. Can you or are you even interested in what that base frequency is of the source? I suspect that this would be needed to isolate the distance and movement of the transmission source. In addition if ET is transmitting radio waves are we looking for Carrier waves with AM or FM signals? Or is that something that will be considered once a viable source is found? |
Aurora Borealis Send message Joined: 14 Jan 01 Posts: 3075 Credit: 5,631,463 RAC: 0 |
I get why your looking for doppler shifts. Can you or are you even interested in what that base frequency is of the source? I suspect that this would be needed to isolate the distance and movement of the transmission source. In addition if ET is transmitting radio waves are we looking for Carrier waves with AM or FM signals? Or is that something that will be considered once a viable source is found? Seti is not looking for doppler shift as much as compensating for doppler shift around the hydrogen frequency. It is looking for any kind of persistent signal that can be differentiated from the normal radio noise of space or astronomical source. We are a long ways from worrying about the actually type of carrier or a deciphering a message. That would be an entirely different project if anything is ever found. |
John McLeod VII Send message Joined: 15 Jul 99 Posts: 24806 Credit: 790,712 RAC: 0 |
I get why your looking for doppler shifts. Can you or are you even interested in what that base frequency is of the source? I suspect that this would be needed to isolate the distance and movement of the transmission source. In addition if ET is transmitting radio waves are we looking for Carrier waves with AM or FM signals? Or is that something that will be considered once a viable source is found? SETI Enhanced is looking for narrow band signals that rise and fall with the rotation of the antenna at Aricebo. The code has to compensate for dopler shifts to see if there is a narrow band signal that is shifted because of rotations and orbits of both the transmitter and receiver. AstroPulse is looking for broad band signals. Once a signal is found, then we might aim an antenna full time to try to decipher the signal. But first we have to find the signal. BOINC WIKI |
JLDun Send message Joined: 21 Apr 06 Posts: 573 Credit: 196,101 RAC: 0 |
In addition if ET is transmitting radio waves are we looking for Carrier waves with AM or FM signals? Or is that something that will be considered once a viable source is found? From what I understand, the AM/FM split in terrestrial broadcasts is split "artificially": If a signal is centered below a certain frequency, then it uses amplitude changes to transmit information [AM]; otherwise it's frequency mod [FM]. But that's just us... |
John McLeod VII Send message Joined: 15 Jul 99 Posts: 24806 Credit: 790,712 RAC: 0 |
In addition if ET is transmitting radio waves are we looking for Carrier waves with AM or FM signals? Or is that something that will be considered once a viable source is found? Actually, we are looking for any signal, and we will work at interpreting it later. BOINC WIKI |
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