EPHFILE is used to specify the location of the JPL ephemeris file. This is only needed if SCHED is being asked to calculate the position of one or more objects using the ephemeris. This is done by including a recognized planet (or other body) name among the sources and not providing a source catalog entry for it (if there is a catalog entry, that is used instead).
The objects that SCHED understands are Mercury, Venus, Moon, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto, and Sun. Topocentric positions and rates will be provided for VLBA antennas if one of these is specified. Geocentric positions along with rates and horizontal parallax are provided for the PM cards for the VLA. Note that SCHED does not understand how to specify moving objects to antennas that don't use the VLA or VLBA control file types.
Under unix, environment variables may be used. For example, if SCHED is defined to mean /users/cwalker/sched, the base area under which all sched stuff is kept (substitute your local directory), then one can specify the ephemeris file with EPHFILE = $SCHED/catalogs/newfile.eph, if that were where it is (it isn't!). Use the setenv (c or t shell) or export (korn shell) to set environment variables.
At the AOC, for now, the ephemeris file is on Brian Butler's computer in the location shown in the example below. There is also a copy in the SCHED catalogs subdirectory.
Note that if planetary observations specified to stations that use the VEX file, the positions passed will not be of adequate quality for correlation and maybe not for pointing.