All of the below will change with the EVLA, which can reach just about any frequency. The following is basically obsolete.
A total of 19 standard observing bands are defined at the VLA. All projects should specify one of these bands, even when frequencies will be modified. This ensures that various defaults at the VLA get set properly. Just pick one with similar properties. For VLBI, one of the ``V'' bands should be chosen.
The tables below describe the bands. The first show the band names along with the synthesizer settings. The column headings are the SCHED names (not necessarily the traditional names in use at the VLA) for these parameters. The second table gives the value that SCHED would want for the VLBI FIRSTLO parameter when using the standard setup. If the frequencies are modified, FIRSTLO would need to be altered. SCHED will insure that FIRSTLO agrees with the frequency that will be obtained with the settings used. The other columns in the second table show the range of sky frequencies covered by the VLA band. The observing frequencies must lie in these bands. Note that the first frequency is that of the edge converted to DC, and then to 600 MHz in the signal sent to the VLBI rack. The other end of the band can be a lower frequency if there is a net lower sideband at this point (the BBC's can be used in lower sideband mode to get a final net upper sideband).
The VLA band VQ will be changed a few months into 2001. The table below gives the frequencies for the new version. The old version was 80 MHz higher in frequency and missed the SiO line at 43.122 GHz. The current plan is to switch SCHED to the new VQ in January 2001, but have SCHED always write LO and IF cards in the VLA observe file for 43 GHz observing, even when using the standard band. After a few months in which any schedules made with the old scheme are flushed through the system, the VLA on-line system will be switch to the new standard. Some months after that, SCHED will stop writing the LO and IF cards for the new standard VQ band.
VLA STANDARD BANDS - VLA SYNTHESIZER SETTINGS
VLABAND VLAFEAB VLAFECD VLASYNA VLASYNB FLUKEA FLUKEB FEFILT
CC 0.00 0.00 3860.1 3810.1 100.00000 200.00000 0000
UU 19.60 19.60 3610.1 3660.1 100.00000 200.00000 0000
KK 17.60 17.60 3860.1 3810.1 100.00000 200.00000 0000
LL -3.20 -3.20 3639.9 3560.1 100.00000 200.00000 0000
XX 13.40 13.40 3939.9 3889.9 100.00000 200.00000 0000
QQ 51.60 13.00 3689.9 3739.9 100.00000 200.00000 0000
PP 0.00 0.00 -689.9 -710.1 115.83750 230.10000 1111
44 0.00 0.00 -939.9 -939.9 112.91875 212.91875 0000
4P 0.00 0.00 -939.9 -689.9 112.91875 215.83750 1111
LP -3.20 0.00 3639.9 -689.9 100.00000 215.83750 0101
18 -3.20 -3.20 3839.9 3810.1 100.00000 200.00000 0000
HH -3.20 -3.20 3589.9 3639.9 115.10000 215.10000 0000
VP 0.00 0.00 -689.9 -689.9 112.50000 212.50000 1111
VL -3.20 -3.20 3839.9 3839.9 100.00000 200.00000 0000
VC 0.00 0.00 3960.1 3960.1 100.00000 200.00000 0000
VX 13.00 13.00 3560.1 3560.1 100.00000 200.00000 0000
VU 19.90 19.90 3510.1 3510.1 100.00000 200.00000 0000
VK 17.50 17.50 3710.1 3710.1 100.00000 200.00000 0000
VQ 51.60 13.00 3510.1 3510.1 100.00000 200.00000 0000
VLA STANDARD BANDS - VLBI FIRSTLO and VLA BANDPASSES
VLABAND FIRSTLO A FIRSTLO D BANDPASS A BANDPASS D
CC 4260.10 4210.10 4860.10- 4910.10 4810.10- 4860.10
UU 15589.90 15539.90 14989.90- 14939.90 14939.90- 14889.90
KK 21860.10 21810.10 22460.10- 22510.10 22410.10- 22460.10
LL 839.90 760.10 1439.90- 1489.90 1360.10- 1410.10
XX 9060.10 9110.10 8460.10- 8410.10 8510.10- 8460.10
QQ 42689.90 42739.90 43289.90- 43339.90 43339.90- 43389.90
PP -274.06250 -280.00 325.93750-350.93750 320.00- 345.00
44 -526.98125 -526.98125 73.01875-123.01875 73.01875-123.01875
4P -526.98125 -274.06250 73.01875- 98.01875 325.93750-350.93750
LP 839.90 -274.06250 1439.90- 1489.90 325.93750-350.93750
18 1039.90 1010.10 1639.90- 1689.90 1610.10- 1660.10
HH 805.00 855.00 1405.00- 1455.00 1455.00- 1505.00
VP -277.40 -277.40 322.60- 347.60 322.60- 347.60
VL 1039.90 1039.90 1639.90- 1689.90 1639.90- 1689.90
VC 4360.10 4360.10 4960.10- 5010.10 4960.10- 5010.10
VX 9039.90 9039.90 8439.90- 8389.90 8439.90- 8389.90
VU 15989.90 15989.90 15389.90- 15339.90 15389.90- 15339.90
VK 21610.10 21610.10 22210.10- 22260.10 22210.10- 22260.10
VQ 42510.10 42510.10 43110.10- 43160.10 43110.10- 43160.10
Note that IF A and C are usually at the same frequency as are B and D.