FE gives four front end specifications for VLBA antennas, one for each IF (A, B, C, and D). Note that the 2cm front end on the VLBA has 4 filters; the on-line system chooses which to use based on the frequency of baseband channel 1, with the dividing points for the filter choice are 12.9, 13.9, and 14.9 GHz. FE = omit may be specified to cause a channel not to be used.
FE can also be used for other stations, especially the VLA and any station that uses a VLBA backend. The 4 receiver names correspond to the first 4 IFs. SCHED can provide appropriate defaults for the VLA based on the frequency requests.
The front ends for the VLA and VLBA are listed here. The maximum ranges are given for the VLBA, which may be considerably greater than the good ranges, especially at 13cm.
Name (FE) VLBA Range VLBA IFs VLA Range VLBA VLA GHz GHz 4 m 4 --- -- 0.058-0.084 90cm P 0.302-0.352 BD 0.23-0.472 50cm - 0.588-0.633 BD --- 20cm L 1.18-1.85 AC 1.0-2.03 13cm S 1.92-2.84 AC 2.0-4.0 6cm C 3.9-7.9 ACBD 4.0-8.0 4cm X 7.7-9.05 BD 8.0-12.0 (also called 3cm) 2cm Ku 11.8-15.6 BD 12.0-18.0 1cm K 20.5-25.3 -- 18.0-26.5 (also called 1.3cm) - Ka --- BD 26.5-40.0 7mm Q 37.6-46.2 AC 40.0-50.0 3mm - 79.7-96.0 BD --- 13cm and 4cm can be observed together on the VLBA using all 4 IFs.