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[aprssig] Iridium humbles APRS

Russ Chadwick russ at wxqa.com
Sun Apr 8 13:45:31 UTC 2012


One aspect of sending packets through Iridium is that there is much less 
chance of large delays sometimes caused by I-gates when using APRS-IS.  
This PowerPoint has results of a study done last year comparing Iridium 
and APRS-IS for carrying APRS packets from balloons.

http://www.wxqa.com/packet_delays_144390.pptx

The balloon flights labeled with callsigns used APRS-IS and the flights 
labeled with AIRCOR used Iridium.  The large delays sometimes seen 
significantly degrade the usefulness for reporting balloon positions to 
the FAA ATC.

Russ
KB0TVJ



On 4/7/2012 6:34 PM, Brian Moore wrote:
> Bob, I can't thank you enough for your APRS system, I am a new ham and 
> still a technician class one at that. I am a huge proponent of APRS 
> and see its benefits for every ham. I hear your frustration when 
> someone shows you up with a multi-billion dollar satellite system like 
> Iridium, and discards APRS as a toy. Although a few weeks ago I read 
> an email from you talking about a satellite constellation for APRS on 
> 145.825, and that could rival Iridium's usefulness. It would not have 
> the bandwidth, nor the operational costs. Something like that would 
> enhance the current terrestrial based APRS network on 144.390, making 
> truly global tracking, messaging, and situational awareness possible 
> without a need for new gear on the user end. People use simple HT's to 
> make contact through satellites every day.
>
> I won't carry on much more, I just wanted to state that at least some 
> of us out here are aware of the boon to overall capabilities APRS adds 
> as a whole, your ideas are not falling on deaf ears. I don't go a day 
> without telling someone about APRS.
>
> Thank you, Brian KD0QCT
>
>
> On Sat, Apr 7, 2012 at 7:13 AM, Jason KG4WSV <kg4wsv at gmail.com 
> <mailto:kg4wsv at gmail.com>> wrote:
>
>     On Fri, Apr 6, 2012 at 4:06 PM, Bob Bruninga <bruninga at usna.edu
>     <mailto:bruninga at usna.edu>> wrote:
>
>     > $950 unit cost...
>
>     > leverage off the DOD Gateway... $250/mo... all the bandwidth you
>     want...
>     > NSF paying $1.2M per year for irridium.. "paying for SIM cards"...
>
>     >  THey just got $2.3B to build the next
>     > network..
>
>     That sounds cool if you've got the application and the budget, but
>     looking at it another way: for the price of an expensive unit, plus
>     monthly service fee, using only a few billion $$ in infrastructure,
>     you can be connected.  Sounds like cell phones.
>
>     I don't see how this can "humble" or even compare to APRS; they are
>     very different communications systems.  As I tell my students, if I
>     have two D7s I have a complete digital and voice communications
>     network.  Doesn't matter if natural disaster takes down the cell phone
>     towers, or if i'm on the dark side of the moon or mars.
>
>
>     -Jason
>     kg4wsv
>
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>





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