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[aprssig] Iridium humbles APRS

Bob Bruninga bruninga at usna.edu
Fri Apr 6 21:06:58 UTC 2012


I was humbled after giving an APRS talk to a bunch of Polar Engineers who do
all the science at the poles.  They have complete 2-way, high-data rate
trackers smaller than ours, and theirs work everywhere on the planet.  About
the size of a pack of cards, and antenna and a battery and you have the
ultimate remote "APRS" system...  though they have the bandwidth to add a
WEB cam and SEE what it sees!

Here are some random notes I made...

Subject: Iridium info ...

100,000 typical trackers, probably 100 in Arctic and 200 in Antarctic...

Short Burst Data (SBD)... about  100k units sold

$950 unit cost...

94.2% overall system reliability over the long term for making a call...

1.9 Kbytes... 350 bytes per burst

1616 - 1626 MHz..  1.6W peak

leverage off the DOD Gateway... $250/mo... all the bandwidth you want...
NSF paying $1.2M per year for irridium.. "paying for SIM cards"...

very expensive commercially...  mostly in the arctic?  Monthly $14/mo and $1
per minute.

phone models :9552 phone.  Now the 9555 phone

Iridium bankrupt in 2011?  But going stong???

Iridium fueled to 2017.  No known expectations of loss of service other than
typical space radiation problems.  THey just got $2.3B to build the next
network..

New mode:  Global Data Broadcast.  A paging capability.  Presently it is
point-to-point.  But will be able to hit multiple units at the same time.

Now it takes 15 to 40 seconds to place a call.  This new system will be more
like PTT.  Just push to talk and all hear it!

SIM numbers:   (these are full phone units I htnk) 400 in antarctic, 100 in
the arctic..

The GPS unit "pass through" means they share the antenna meaning you lose
about 3 dB link margin if you also have the GPS option.


Bob, WB4APR




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