[amsat-bb] Re: PCSAT-1 Mobile Communications Test

Jim Jerzycke kq6ea at pacbell.net
Wed Jan 17 17:06:59 PST 2007


Wonderful stuff, Bob!
I'll give this a try when I get back home.
73, Jim  KQ6EA

--- Robert Bruninga <bruninga at usna.edu> wrote:

> > ... approved the following Eagle communications
> payloads:
> > c.  A low rate text message system, like SMS. It
> will 
> > operate on U/V-bands and be usable over 75% of the
> orbit 
> > by a small terminal on the ground.
> 
> Sounds just like APRS... <grin>
> 
> Of course, I know that they are not talking about
> APRS, but then
> when one considers the ten thousand or so D7 and
> D700 radios
> with APRS messaging built into the front panel, one
> wonders why
> we don't have more APRS satellites to use for this
> purpose.
> These days, PCSAT-1 is doing great links to
> mobiles...
> 
> In my mind, one of the best applications of any
> Amateur
> Satellite is to serve the mobile operator, since the
> fixed
> operator in most cases has access to many other
> communicaitons
> paths already, such as the internet and satellites
> that need
> beams.  But the mobile ham operator could really use
> a satellite
> link!
> 
> Again, the point of this post is not at all to
> suggest a change
> to the Eagle plans, not in any way, but to remind
> future
> satellite builders that there is this vast mobile
> Ham radio
> community that already has a built-in 1200 and 9600
> baud front
> panel radio message and tiny-web-page display
> capability out
> there fully fielded by thousands of operators that
> could benefit
> from PCSAT type uplinks and downlinks.
> 
> See the Tiny-Web-Page applications of the D7 and
> D700 radios
> presented at the TAPR/ARRL DCC 2000:
> http://www.ew.usna.edu/~bruninga/aprs/TWP.html
> 
> We tried to extend the mission of PCSAT-1 with
> PCSAT2, ANDE and
> RAFT, but all of those have limited lifetimes.  If
> you have a
> mobile D7 or D700 and haven't tried PCSAT-1 during
> this current
> recovery period, you should try it.  On any good
> pass, I see as
> many as a dozen stations and messages on my mobile. 
> Simply tune
> your D7 or D700 mobile to 145.825 and leave it
> overnight.  Next
> morning, look to see who all you see on the front
> panel of the
> radio.  Also check the MSG list.
> 
> Here are some hints on the best way to do that
> experiment:
> 
> 1) Observe call of the last normal APRS station
> heard (so you
> can tell what is new and what is old in the
> morning).
> 2) Be sure your RANGE LIMIT is set to 0, and not 50
> miles or so,
> because the radio will filter out all satellite
> packets since
> they come from 500 to 1500 miles away unless it is
> set to 0.
> 3) Check that your radio CLOCK is set so that you
> can see the
> packet times of arrival
> 4) Clear out any old incoming messages to make room
> for
> Satellite messages.
> 5) Park your car to see the sky above about 15
> degrees especialy
> from the Southwest through North East.  
> 6) Please, only do unattended at night so that you
> do not
> conflict with command stations during the day.  
> 
> Next morning, check the station list and message
> list on the
> radio and see what you got!
> 
> Oh, for unattended operation like that, be sure your
> TX rate is
> only one packet per 5 minutes so you will equitably
> share the
> channel with dozens of others...  If we overload
> PCSAT-1 in the
> dark we will kill it. We won't see a positive power
> budget until
> March for only a week.
> 
> To see everyone live, who is playing on PCSAT-1, see
> http://pcsat.aprs.org
> 
> Good luck!
> 
> Bob Bruninga, WB4APR
> Naval Academy Satellite Lab
> 
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