[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Satellites Everywhere




Apparently-to: tlang@freeway.apana.org.au
From: Bob Bruninga <bruninga@nadn.navy.mil>
Subject: [amsat-bb] Satellites Everywhere

Let me first appologize for my exuberance!    But...   :-)

Now that I added satellite tracking into APRStk.exe I am amazed that
there seem to be satellites overhead most of the day.  For those
APRS operators waiting for someone to drive through your map, the
Satellites are THERE most of the time and they are moving... FAST!

I think maybe many hams might think that the only satellite they can
work without special equipment is AO27 FM voice.  This is no longer true.

For the last year, for thousands of amateurs who have the Kenwood THD7
HT or TMD700 Mobile DATA radios, there are at least 11 satellites that you
can receive with your Handheld or mobile!  All you have to do is to be on
the right frequency at the right time and set the internal TNC to 9600
baud.  (and tune downward 5 KHz for doppler every few minutes).

I now carry a small 4 element beam with me almost everywhere I go.
With it, I can work AO27, or SO35 or watch the downlink packets of
any of the 9600 baud birds on the front panel of the mobile radio.  No, I
cant "work" any of them (yet) without a laptop, but just receiving them
just about anywhere at any time with a handheld beam is to me the joy of
amateur radio and inspires me to think about new applications.  (I have
motors on order for a car roof AZ rotator!)

YES, during an overhead pass (above say 40 degrees) you can even decode
packets on your mobile WHIP antenna!  But these only occur for a
brief minute or so about twice a day per bird... But still, that is over
a dozen passes a day to play...  Or hold the small beam out the window,
and see packets on any of 44 passes a day.

CAVEAT:   I am including the 4 new satellites launched 2 days ago (not all
of which may become fully operational)...  and AO27/SO35 voice in the 11.

SUMMARY:  Just dont overlook how easy it is these days to receive the 9600
baud downlinks with no muss-and-no-fuss....(only $$$'s).   And no matter
where you are in the world, or how isolated, these satellites are there.
And with the equipment in your car, even basement and apartment dwellers
can play.  I have a favorite hilltop about 1 minute from my house where I
go to take low elevation passes... (I have nothing at home, though today,
I copied AO27 and one of the pacsats using the handheld beam INSIDE the
house!)

With these Kenwood radios, any mobile with a small 18 inch beam can work
the satellites.  Its time to start taking advantage of this mobility..
I have posted a concept I call ASTARS to discuss the possibilities...

   http://web.usna.navy.mil/~bruninga/astars.html

NOTE:  The Kenwood radios are not perfect.  Your mileage may vary.  But
being an all-in-one 9600 baud packet radio with display, is certainly a
great tool for furthering the state of mobile amateur satellite
operations.

SATELLITE TRACKING:  I wrote APRStk to give a visual timeline of when
passes are due over the next 2.5 hours and since the satelites are moving
on the same APRS map as all the other APRS mobiles, it makes it easy to be
aware of the constantly changing picture.  An APRStk screen shot is on the
above WEB page.  (The .exe needs to be run within an existing APRSdos
install)

By using APRStk on my old dos PC in the corner, I now always have a view
to the local APRS activity AND any satellites in view!  Unfortunately
APRStk is kind of slow on an 8 MHz PC with no co-proc, but on anything
faster, and with auto-REDRAW enabled, it will ALWAYS show you what is
happening.  Even if you are zoomed in too far on the map, to watch locals,
if a satellite comes above 5 degrees, the MAP background will change color
according to the elevation angle.  If it turns RED, then the satelilte is
over 40 deg and you should hear it on an omni (with no coax losses).. or
with coax and a pre-amp.

The neat part of the display is at the bottom, where it shows you
graphically, the next 2.5 hours of passes coming up...

AND FINALLY!  APRStk can send and receive updated KEPS over the air with
only one key press.  The idea will be that Satellite one-line keps will be
transmitted one packet per hour on  local APRS networks and thus, you
will never have keps more than one day old!

de WB4APR, Bob








----
Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
--
|Fidonet:  bruninga@nadn.navy.mil 3:633/284.100
|Internet: bruninga@nadn.navy.mil
|
| Standard disclaimer: The views of this user are strictly his own.


----
Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org



AMSAT Top AMSAT Home