Returning to Equation 5, note that the scaling factor between
``adjacent'' VLA configurations (e.g., B and C) is
. The scaling is inexact because the North arm uses some
non-scaling antenna locations in the A and D
configurations. This scaling factor is near the ratios between the
default VLA frequencies at 20 cm and 6 cm and between those at 6 cm
and 2 cm. The VLA therefore has similar resolutions at 20 cm in
the A configuration, at 6 cm in the B configuration, and
at 2 cm in the C configuration. (Such rough three-frequency
scalings also apply for the B, C, and D
configurations, of course.) These scalings make the VLA a powerful
tool for studying the frequency-dependence of extended emission
without changing the angular resolution.