Use of the default block
As the name suggests, the default block allows observers to modify system defaults without the need to alter system files.
Common problem:
While the format for any valid card in the default is the same as those modifying source cards, use of the leading slashes (ie, //DS) are not adequate in designating bands! The file checking programs will only check the card format but will not alert you to their mis-use!
Example:
/DEF
//DS 3 <- Observer desires 3-second integration...but at what band??
/EDEF
Corrected example:
/DEF
XXDS 3 <- Observer selects 3-second integration for X-band only!
/EDEF
Note that this is the same format found in the SUBn file...