[amsat-bb] Manual Tracking XW-1

Robert Bruninga bruninga at usna.edu
Thu Dec 17 06:25:20 PST 2009

XW-1's orbit is quite easy for manual tracking, though not quite
as easy as it is for AO-51 ECHO or GO32...   

Just remember these facts:
* XW-1's orbits come over 17 minutes earlier each day.
* There is a pass 109 minutes earlier and/or later
* Once a week (6 days) add about an hour and a half (basically
109 - 17)
* The pattern repeats every 6 days but 6 minutes later

Basically the exact pass pattern repeats every 6 days, but
unfortunately slips by 6 minutes a week so a permanent repeating
schedule like we use for AO-51 and GO32 for months is not
possible unless you want to add the 6 minutes each week.  
See www.aprs.org/MobileLEOtracking.html

This way say you are far from a PC, all you will need to do is
monitor the AX.25 packet downlink for several hours some day
with your APRS mobile.  Once you get a packet, then you can
manually derive the rest of the passes for your trip.

(I hope they eventually turn on APRS digipeating on the AX.25
channel for such wilderness travelers..)

Bob, WB4aPR

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