Re: SETI ET's problem with Doppler.


prewar (prewar@btinternet.com)
Fri, 10 Sep 1999 09:32:00 +0100


Yvan Dutil wrote:

> Second, the Dopler drift allow you to differanciate a
> guinuine ET signal for a local transmitter.

Hi Yvan,

Even if ET did 'step sweep' would we not still be able to see his
doppler shift within the smaller frames that each step provided.
Say, we reduced our 'bin' sizes to .1 or 1Hz which would increase our
sensitivity, would it not? Within this smaller frame his doppler shift

would still act as a differentiation beacon. ??
Many searchers are using SSB with 3KHz passbands (some using
R2 with 20 KHz pass) Receivers. Those looking towards/away from
our Earth's rotation around our Sun (within 45 degrees) already suffer
a
plus/minus 100-150 KHz Doppler shift from 1420 MHz. Is this not so?

This is in addition to any other Doppler shift at ET's end, and other
shift
due to our moving nearer/further apart. I do hope that I am wrong
in all this. :-) What chance do we really have if ET's TX freqs stay
fixed ??

Regards

albErT !!



This archive was generated by hypermail 2.0b3 on Sun Oct 10 1999 - 15:46:34 PDT