>  In reference to "1" day - 24 hours, how does the "Frequency" 
> option work compared to the "Calendar" option?
> 
> Does "Frequency" start at Midnight to Midnight? Or can the 
> "start" be set on the start time?

Frequency means, um, "frequency."  Length of time from the last
successful backup run of a given schedule on a given client before the
scheduler considers starting it again.  (There's a minor special case if
the frequency is a multiple of 24 hours to keep the start time from
creeping a little later in the window each time it runs, but not
important here.)

> My Policies are schedule to run between 17:00hrs and 7am.  I am using
a
> "Frequency" of "1 day".  It appears that the policy is kicked off at
> 17:00hrs and also after midnight.

You have pushed the Calendar radio button on the schedule(s).  Push the
Frequency button unless you have a serious reason to manage this on
specific days.

> Any suggestions?

Yes.  Read The Fine Manual.  NetBackup System Administrator's Guide,
Volume I.  Managing Backup Policies | Schedule Attributes Tab |
{Calendar|Frequency} Schedule Type

And you're not alone.  The post-midnight job that is a logical
consequence of a day-spanning window with both days checked in
calendar-based scheduling is not intuitively obvious.  There is logic in
later NetBackup versions to handle this after the first occurrence,
documented in the SAG.