[aprssig] KC2TUA/KC2UFG Ballon QRM

Bob Bruninga bruninga at usna.edu
Mon Mar 23 00:34:16 EDT 2009

>> Yes, each digi will put out one packet 
>> once a minute from the balloon. But that 
>> is no different than any other mobile driving
>> around at a one minute rate.
> Absolutely incorrect. The mobile is only 
> heard by the adjacent digis. A balloon at 
> 30,000 feet is impacting every digi (and 
> every other APRS user) over an area of 
> about 75,000 square miles...

I have to stand by my statement.  The impact on each digi is still only the same as one mobile at a one minute rate.  Surely that does not do damage to any local area that has all kinds of guys driving around at a 1 minute rate wasting air time during their commute which no one cares about.  While a balloon taking no more bandwidth is sure a lot more interesting.

> Yeah, but potentially into the "local area" 
> of scores or even hundreds of digis, 

So?  It still has no more of an impact on any local area than just one more mobile driving around at a 1 minute rate.  Though it seems this one sure did last a long time..  Dropping the rate for long duaration missiosn would have been prudent.

> and it doesn't listen to see if the frequency 
> is clear.

The APRS channel is never clear when you are above 1000 feet, I guarantee it.  That is why all balloons and aircraft are recommended to ignore DCD while in flight, else they will never transmit.  And what good is an APRS device on a very rare and exciting aero-mobile if it cant transmit?

Yes, this event got a lot of attention.  But it was more fun than watching 20 mobiles driving around here all day doing nothing related to Ham radio, and with no receivers so they can even communicate.

Anyway, looks like it was fun for all...

Bob, Wb4APR

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