[aprssig] ISS pass at 1115 EST today

Bob Bruninga bruninga at usna.edu
Fri Jan 28 12:16:59 EST 2011

> What's the downlink/uplink freqs.? 

Sorry, I need to remember that not everyone has been on APRS for 18 years.

Early adopters remember that we gave up the original APRS USA 145.79
frequency to give margin for astronauts on 145.800.  All downlinks from the
ISS/Shuttle are on 145.800.  

Unless it is packet.  About 5 years ago we convinced them to put the APRS
downlink on the APRS satellite frequency of 145.825 for compatibility there.
This has been great when we have 2 or more APRS satellites active.  Although
the APRS satellites are currently having problems, the ISS has risen to the
occasion and seems to be on APRS all the time now.

Monitor 145.825 for 24 hours and you can easily hear when ISS is coming
over.  In the USA you will hear 6 passes a day separated by 91 minutes or
so.  Once you hear the pattern, it repeats every day but the time of a pass
is 23 minutes LATER the next day.  But the long term location of the oribt
is moving earlier by 26 minutes a day.

Right now in the USA there are 6 passes a day over the USA between 4 AM and
noon, but this pattern is getting earlier each day.  In 2 weeks all the
passes will be before sun up.  In a month or more, the passes will be in the
afternoon commute for a few weeks.  Etc.

See the patterns on this page: http://aprs.org/MobileLEOtracking.html

Once you visualize what is going on, you don't need any computer to make
satellite predictions.  You can pretty much estimate each day's passes.
Remember we have had AMSATS for almost 50 years and we only used PC's for
tracking them for the last 30...

Anyway, a great way to work the satellites with your FM mobile on long

Bob, Wb4APR

> ISS has a voice contact with Kentucky school today at 1115 EST.
> 1015 CST. Going west to east across northern USA from Oregon to Marlyand.
> Anyone with an HT near a window should be able to hear it.
> Being right across the central USA, most everyone can hear it.
> A western window will get the early part of the pass.
> Then over the north, finishing to the east.
> Enjoy.
> Bob, WB4APR

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