Many of the file designs are for a frequency of 37.5 MHz, which is
convenient in giving quad corners at +/- 1 meter, and dipole ends at 
+/- 2 meters. Scale to desired frequency. Their file names are usually
simple, such as DIP.GEO

Other designs are for specified frequency, such as 2QUAD20.GEO

Elements are constant diameter: if tapered elements are used, the 
taper correction must be calculated and used.

See the PUBLIC section for files of dimensions of a number of common
Amateur antennas. These can be analyized by programs in that section,
by MiniNEC, NEC or ThinWire: the last two are the most comprehensive,
and usually the most accurate.