MA and Time Calculations



This group of files was designed to insure accuracy in various amateur
satellite calculations.  They are not necessary for successful operation,
but they can enhance most operations on Oscar 13.

All of these calculations can be done easily on a hand calculator.  The
programs were written for the computer to increase accuracy, not speed.

If you find them of some value, enjoy, and if you are not an AMSAT
member please consider joining.  Their address for infomation:

                       AMSAT
                       P. O. Box 27
                       Washington, D. C. 20044

The programs take into account timing errors in the satellite's
computer.  They are satisfactory for short term predictions. (On the order
of a week to ten days).  An ongoing program of time calculations should
increase this accuracy for long term predictions.  Stay tuned.

The source code is NOT available.  This has nothing to do with proprietary
rights.  I don't want to be embarassed by my "spaghetti" code.

Recommendations for improvement are solicited.  I can be reached on any of
the birds, the 20 meter AMSAT net, 14.282 on Sundays or by phone. WB6BDY
has a good BBS at (619) 279-3921.  I can also be reached there.

                                 73,
                                      Dave  WB6LLO, San Diego, CA
PROGRAMS:

SATCALCS.TXT----This file.

ADDHOURS.EXE----Entry is hours, minutes, and seconds.  Adds them.

SUBHOURS.EXE----Entry is hours, minutes, and seconds.  Subtracts them.

DECHMS.EXE------Converts decimal hours to hours, minutes and seconds.

HMSDEC.EXE------Converts hours, minutes and seconds to decimal hours.

MACALC.EXE------Converts Keplarian factor "Orbits per day" to
                minutes/phase angle(MA count).  It then calculates total
                time for an operating period based on MA units.



To return to DOS go to the menu and enter "Q".












MAEVENT.EXE-----This program predicts the time of an MA event.  Input is
                the mean anomoly number and the NASA orbit.  This gets
		tricky.  NASA is not consistent with the orbit numbers.
		In February of 1989 their orbit #514 equals "program"
		orbit #512.  Make entry with the NASA#.  The program
		makes the correction, and the printout is consistent
		with the NASA#.

		This will probably change.  Record an actual event on
		the satellite, experiment with various orbit #'s to
		determine the correct number.  Don't write to me on this
		one.  Write to NASA and your congressman.

MAPRINT.EXE-----This program prints MA event information predictions.
		Entry is made with MA and an actual event time.  An MA
		event prediction could be used, of course.  However, to
		increase accuracy, it is recommended that the entry be
		made from an actual event.

		Short term accuracy is excellent.  Long term time
		evaluations will improve accuracy of updates.
		Make certain you manually insert correct orbit numbers.

		The program is designed to indicate every other orbit
		number.  About every eight days it is necessary to sub-
		tract only one orbit interval of 33 min., 18.5 seconds
		and rerun the program.  This is probably a good interval
		to make minor corrections based on an observed event.

RPEETNEW.EXE----This one calculates and prints repeat MA event times.
		Entry is made with MA event, e.g. MA 100, and event time,
		preferably from observation.  Printer will record
		subsequent predictions.  Again a two orbit interval is
		built in.  Manually record orbit numbers, and watch for
		a single orbit change.

RPEETSUB.EXE----The same as RPEETNEW for the screen.  It is a quick and
		dirty way of making a single event prediction from a
		known event.
		
ORBITNO.EXE-----Used to determine the orbit number.  Entry is the date and
                an observed event time.  This can be from any up to date
           program, or for increased accuracy and actual observed
                event.  Round off to nearest orbit number, and confirm with
                an event prediction. 		
		

	Send an SASE for information on the "NO DITTERS".

	MATCH any receive frequency in the passband with your
	transmit frequency INSTANTLY.  Send and SASE to:

			Dave Guimont, Jr. WB6LLO
			5030 July St.
			San Diego, CA  92110

				for a FREE brochure.