BAND provides a simple way of requesting an observing frequency. SCHED has an internal table of standard center frequencies that can be called upon with BAND. If BAND is specified, and FREQREF is not, SCHED will get the observing center frequency from its internal table and will calculate, based on the NCHAN, BBFILTER and POL parameters, the actual channel frequencies to use to center the observations at the desired frequency.
The bands and centerfrequencies are in the table below. When a bandwidth is not zero, that center frequency is used if the observation total bandwidth is the given amount. This allows the center to shift with increasing bandwidth, which is especially useful at 21 cm where the radio astronomy band is near the edge of the tuning range for the preferred IF at the VLBA.
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SCHED STANDARD OBSERVING BANDS
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Center
BAND Frequency(1) Bandwidth
'90cm' 330.49 0.0
'50cm' 610.98 0.0
'21cm' 1465.49 128.0
'21cm' 1435.49 64.0
'21cm' 1416.49 0.0
'18cm' 1658.49 0.0 (2)
'18cm' 1653.99 0.0 (3)
'13cm' 2295.49 0.0
'6cm' 4990.49 0.0
'4cm' 8415.49 0.0
'2cm' 15285.49 0.0
'1cm' 22235.49 0.0
'24ghz' 23800.49 0.0
'7mm' 43135.49 0.0
'sx' 2295.49 and 8415.49 0.0
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1. Note, these are subject to change as the choices
are discussed with the community.
2. Most 18 cm observing.
3. For 32 MHz wide observations involving Jodrell, but not the
phased VLA. Avoids RFI at Jodrell. But must be higher to fit
in the VLA IF's.
Specifying the BAND works well when most setup file parameters are defaulted. But if the user insists on specifying many of the other parameters, such as IFCHAN, BBC etc, in non-standard ways, the program may not do the right thing. It is likely that this will generate an error when the setups are checked.