Important Notes - Please check these

• The world of VLBI is in a transition from the traditional backends to the newer digital backends such as the RDBE and the DBBC and to newer recording systems such as the MARK5C. SCHED supports many of the digital backends and new recorders. But not all of the examples have been converted yet and some sections of the manual may still be somewhat dated. We're working on it.

• The MARK5A recorders were removed from the VLBA in December 2013. All projects must now use the RDBE. All VLBA stations have two RDBE units for a total of 8 channels with the DDC. Most MARK5A setups can be duplicated with this system. Most of the standard setups with names like v6cm... will work with the DDC. As of April, 2014, half of the BBCs in the legacy system will be unplugged. The remaining ones are still used to collect pointing data and some old style calibration data, mainly for test purposes.

• Many requests for help from SCHED users are the result of trying to specify more information than necessary. SCHED knows how to set up the details for most observations at most stations. Before trying to figure out LO settings or, for example, details of VLA setup parameters, try just setting the final frequency you want and let SCHED try to determine the details based on the freq.dat file. In most cases, you only need to set NCHAN, BITS, BBFILTER, FREQREF, FREQOFF, NETSIDE, and POL. In fact, you can just set BAND rather than FREQREF and FREQOFF and SCHED will give you the standard default frequencies.

• Mark IV users please see the Mark IV Section for information about mode and mode change restrictions.

• If you are using B1950 coordinates, you should worry about the ``observe'' date to use for precession. Please see the discussion of the input parameter PRECDATE. But you really should not be using B1950!

• Please note that all setup files intended to be used for spectral line observations using DOPPLER must have all channels distinguished, in the setup file, by frequency and polarization. In the past, it was common practice to set all channels to the same frequency, and let the doppler calculations separate them. But the requirement to deal reasonably with single polarization sites in dual polarization observations forced SCHED  to be able to relate channels from each station to channels from other stations within the setup file. This is mentioned here because it has proven to be the source of considerable confusion.

• Try the plot capability (UV, El vs time etc). It's easy to use and should help with planning and with understanding what your schedule will provide. See the ploting section for details.

• This manual is written with LaTeX and latex2html. It is meant to be read using a browser. A postscript version could be generated for printing. But it is over 280 pages long and should be updated with each release. Printing it would be considered unfriendly to the world's forests. The authors have not printed it in many years.