Questions on Radio Astronomy Techniques
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						DTE. 1999-07-27.

1.  How many Jansky is a 1 mw transmitter on the moon?  Assume
the radio telescope receiver uses a spectrometer with a
resolution of 1 MHz.

2.  How can radio astronomers regularly receiver a signal that's
a million times weaker than the background noise, while for
communications you need a signal a million times greater than
the noise?

3.  For receiving pulsar signals from the Crab nebula, within a
certain range of antenna size, a big antenna gives no better
signal-to-noise ratio than a small antenna.  Why?

4.  What, in degrees K, is the theoretical limit to sensitivity
of receivers at mm and sub-mm wavelengths?

5.  The NRAO 12 Meter Telescope maps a certain object, and so
does the BIMA interferometric array, at the same frequency.  The
BIMA telescope uses 6-meter dishes, with baselines ranging from
20 m to 100 m.  When the results are compared, there appears to
be no correlation between the 2 maps.  Why might this be?

6.  A position-switched spectral line observations of CO in
the direction of the Pleiades came up with a very strong negative 
spectral line feature.  Why might this be?

7.  What technique does "seti@home" use in analysing data for
possible extra-terrestrial intelligence?

8.  Explain how a 2-element interferometer filters out a single
Fourier term of the sky brightness distribution.

9.  Since continuum emission occurs at all frequencies, why
do we bother to observe at different wavelengths.  What extra
information does this give?

10. An observer uses frequency switching to measure some
weak CO emission from a distance radio source.  He finds he
has terrible spectral baseline problems.  What does that mean?
What might he be doing wrong?