Just a thought - and I know its on a different frequency etc .. blah blah. BUT I wonder if the seti processing could have found that transmission from Hughens as if floated down, as a signal in a wu. It was faint and took the large dish's to record the info.

Nairb

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> Just a thought - and I know its on a different frequency etc .. blah blah.
> BUT I wonder if the seti processing could have found that transmission from
> Hughens as if floated down, as a signal in a wu. It was faint and took the
> large dish's to record the info.

The probe would have to be transmitting on the same frequency that SETI is listening to. Hydrogen I think.

The probe would have to be transmitting on the same frequency that SETI is listening to. Hydrogen I think.

Yes - I know its not on the same frequency as seti - The point of the question is more along the lines of How do you test that the seti processing works. ?

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> The probe would have to be transmitting on the same frequency that SETI is
> listening to. Hydrogen I think.
>
> Yes - I know its not on the same frequency as seti - The point of the
> question is more along the lines of How do you test that the seti processing
> works. ?
>

Well, barring the huge upfront issue of different frequency, the signal would've been captured by the radio dish at Arecibo and logged in the data-tape that they get and it would then be split into WUs and sent to various computers. If anything, as we looked at the graphics, it would've spiked rather noticably due to the proximity of the signal to Earth. Huygens' signal was weak indeed but given that it's only a few hundred million miles away rather than light years, the signal would've been stronger.(This is also assuming, of course, that Arecibo could pick up something on the order of a few watts of generated energy.)

How do we test it? I think they slip in some test elements to see if there were any bugs and I know that earlier SETI searches used known astronomical references to calibrate their instruments.

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What the Green Bank radio telescope has detected is only a ‘carrier’ signal. It indicates that the back cover of Huygens must have been ejected, the main parachute must have been deployed and that the probe has begun to transmit, in other words, the probe is ‘alive’. This, however, still does not mean that any data have been acquired, nor that they have been received by Cassini. The carrier signal is sent continuously throughout the descent and as such does not contain any scientific data. It is similar to the tone signal heard in a telephone handset once the latter is picked up.

Only after having received the data packets at ESOC will it be possible to say with certainty whether data were properly acquired. The first data set from Cassini will reach ESOC in the afternoon. Additional downlinks will follow throughout the evening and night for redundancy.

Further analysis of the signals will be conducted using other three independent data acquisition systems at the Green Bank Telescope. In addition to the GBT, sixteen other radio telescopes in Australia, China, Japan and the USA are involved in tracking the Huygens probe.
...

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Radio astronomers confirm Huygens entry in the atmosphere of Titan

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I recall reading an article some tmie ago (was it linked from the Classic web pages???) that described how the system has been tested.

If I remember correctly, they tune the recievers to different frequencies and listen to old bits of space hardware floating around - I think the Voyager probes were used at extreme distances - much further out than Huygens and much weaker signals.

Also I rember seeing an article on the Seti Classic pages that shows how they test the software by processing satelite doppler shifts.

So in principle, it is reasonable to suggest that Huygens transmisons could be used as a test source, but they have many other sources available which are probably weaker in amplitude and use less complex in modulation schemes.

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