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MMA Memo #68
A Millimeter Phase Stability Analysis of the South Baldy and Springerville Sites
M.A. Holdaway (NRAO)
1991/11/22
Site testing for the Millimeter Array has been underway at South
Baldy, NM for about four years and at Springerville, AZ for about two.
In addition to opacity measurements, the tipping radiometers at each
site have performed stability measurements at 230 GHz which yield the
Allan standard deviation at various averaging times of the sky
brightness temperature fluctuations. The Allan standard deviation is
related to the phase structure function $D_{o}(\rho)$ if the velocity
is known (Treuhoft and Lanyi, 1987), so in principla we could take the
Allan standard deviation "profiles" and determine the behavior of an
interferometer of baselin p. The details of this problem do not lend
themselves to an analytic solution, so we have turned to computer
simulations. The simulations indicate that South Baldy is a better 1
mm site than Spingerville. At 230 GHz, the two sites are comparable
in the most compact configuration and in the large configurations when
selfcalibration is possible. When selfcalibration is not an option,
phase stable interferometry in the A and B configurations would be
possible at South Baldy between 10% and 20% of the winter time. At
Springerville, phase stable observing in the two large arrays would be
very rare.
View a pdf version of MMA Memo 68.
Last modified: 2002-01-23
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