[amsat-bb] Oscar Locator‏ (easy also without it)

Robert Bruninga bruninga at usna.edu
Sat May 28 14:11:47 UTC 2016

Yes, for knowing when satellites are in view (on vacation  for example) you
don't need no stinkin computer.nor even an oscar locator.  Just a pen and
paper.  Works anytime, anywhere.

You only need one number.  And that is how many minutes earlier or later an
orbit is per day.  Calculate this once for each satellite of interest and
that is all you need to remember.

See http://aprs.org/MobileLEOtracking.html

For PSAT it is 15 minutes earlier each day, and of course 100 minutes
between passes.

For ISS it is 23 minutes later each day and then every 91 minutes

With these factoids, all you do while traveling on vacation is to set your
mobile to the downlink.  Sometime that day you will hear your bird.  Just
note the time.  And by using the above numbers you can estimate all passes
every day.

The ISS even has another feature, its ground track approximately repeats
every other day.  So once you see the pattern you can know what to expect.

With a hand held Arrow antenna, you just swing around and FIND the
satellite and then operate the remainder of the pass.  Again, these times
are approximate given that the very first pass you hear, you may not be
sure which one in the daily series it is and the time to next pass creeps
later on descending passes comapred to ascending passes.

But it is fun.  I especially like to put my mobile APRS over on the Space
APRS channel when I am out in the wilderness traveling and wait for ISS to
come alive.  Then I can quickly jot down all expected passes or the day and
see how that fits into my wife's intentions for the day.

And with a D72 HT that can hear the ISS on a rubber duck, one can always
find the ISS.


On Sat, May 28, 2016 at 1:35 AM, Kevin Deane <summit496 at live.com> wrote:

> I am still interested in the way that the old timers used the Oscar Locator
> ‏ and have gotten very few responses in my past inquires... I think there
> was one maybe two people actually took the time and sent me in a direction
> they thought was clear but I might have to see it done or something. I
> suppose you could use keps off of any tracker and if worse came to worser
> you could even use months old keps and just keep track and listen...I know
> they do not change that much over time but enough eventually.
> My point is I would love to show my nephew how to track a sat in space
> with a pen and paper and two radios and two antennas ... That would be
> great, no cheating...Killer Boy Scout stuff right?
> Thanks for any input.
> Kevin
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