[na-user] NA problem solved -- check MASTER.DTA

k8cc k8cc <k8cc@mediaone.net>
Sat, 27 Jan 2001 10:48:16 -0500


Let me clarify some things concerning MASTER.DTA files.  I'm copying this 
to the reflector because others might be interested in this information.

The MASTER.DTA format was invented by K1EA for use with the CT logging 
program.  Eventually NA, TRLog and perhaps others implemented the "Super 
Check Partial" feature similar to CT and adopted the MASTER.DTA format.

The MASTER.DTA file has a very unusual format, so I am curious whether the 
MASTER.DTA you modifed is really in CT format, or something simpler that is 
intended for another program?  For example, I think there is a file 
maintained by some VHFers which might be called MASTER.DTA but includes 
other information such as grid square.  This file is *NOT* a K1EA-format 
file and is not usable with CT, NA or TRLog.  If you can read MASTER.DTA 
with a text editor, it is NOT a K1EA-format file.

MASTER.DTA starts with a set of pointers to "streams" of callsigns within 
the file which contain a particular two-letter fragment.  The pointers are 
calculated using the ASCII values of the characters in the fragment, and 
the only valid characters are 0-9, A-Z (uppercase only) and the slash 
bar.  Anything else (including spaces) will probably send NA into the 
weeds.  (Because of the speed at which the MASTER.DTA file must be decoded, 
NA does not include a lot of error-checking.)

Perhaps this is better explained by example.  Suppose I enter "N0" in the 
callsign field of NA and auto-check kicks in.  NA calculates the pointer to 
the beginning of the stream of callsigns which include "N0".  It also 
calculates the pointer to the beginning of the "next" stream of callsigns 
(i.e., those which include "N1") and backs up one byte to determine where 
the "N0" stream ends in the file.  NA simply starts at one end of the 
stream and pulls out callsigns (which are separated by nuls) until the 
window is full or the end of the stream is reached.  (There is more to it, 
such as dupe-checking the call, or if the partial is longer than two digits 
but this is the basic process.)

Addressing your points:

>After some correspondence with K8CC, I've discovered that I've
>unwittingly been using a bad DTA file.  I decided that I'd enter the
>names of all my friends in the DTA file as (for example) K8CC/DAVE, so
>that I was reminded in the middle of a contest and could at least say
>hello.  I also had entered some calls that genuinely had slashes, such
>as F/ON8KO.  Anyway, the DTA rules are that just letters and numbers are
>allowed.  Furthermore, the database should be in alphabetical order to
>operate correctly.

Slashes are OK, but as described above anything other than 0-9, A-Z or a 
slash is not.  The calls doe not have to be in alphabetical order in 
MASTER.DTA, but if they're not they won't show up in alphabetical order in 
the NA F8 window. (Sorting these on the fly would require tremendous 
amounts of memory and would slow the program to a crawl.)  Also, keep in 
mind if you add things like a name to a call (i.e., K8CC/DAVE) that the 
columns in the F8 window are defined by the longest entry in that column, 
so with longer entries you'll see fewer calls in the window.

>I haven't been able to find any rules published as to what is the
>correct DTA format, and would appreciate knowing what these are.  I have
>been in the habit of creating my own DTA files from past entries in the
>IOTA contest and some others, and would like to make sure these are in
>the correct format.

To the best of my knowledge, there is no published specification for the 
MASTER.DTA file.  I "reverse engineered" the file to make NA work with 
it.  Generating a MASTER.DTA requires specially-designed software - its not 
something you can create with a database like MS-Access.

K1EA invented MASTER.DTA, and Jim, AD1C has been publishing MASTER.DTA 
files associated with CT for years.  Jim has been kind enough to share the 
.DTAs he generates with the providers of NA, TRLog and perhaps others.  My 
experience has been problematic with others who have published .DTA files, 
usually because the calls are not sorted alphabetically, or callsigns 
appear multiple times in a single callsign stream.

Late last year, AD1C announced he would like to get out of the MASTER.DTA 
business.  I and my contesting cohort (and NA user) Tim, K9TM volunteered 
to take over the task.  An exact timetable has not been set, but sometime 
in the near future the torch will be passed.  Nothing will change from the 
standpoint of the user - you'll still be able to find recent versions of 
MASTER.DTA in all the places you currently find them.

I hope this explanation is useful and not just a waste of bandwidth.

Dave Pruett, K8CC
DATOM Engineering

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