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[aprssig] BALLOON unproto paths

Robert Bruninga bruninga at usna.edu
Tue Apr 5 02:41:54 UTC 2005


>>> "Russ Chadwick" <russ at wxqa.com> 4/4/05 9:54:37 PM >>>
>EOSS is somewhat different from other balloon organizations 

Yes, not trying to change the way you do thinks.  Just making
sure everyone is aware the RELAY and WIDE are obsolete and
we are doing everything we can to get rid of them.  We didnt
want you guys to be caught off-guard.

>When we use 144.390 MHz, we always use a single WIDE...

Yes, so since that is going away, then.. what to do now...

>If we... change to WIDE1-1  then the mountain top digis will 
>repeat the packet and ... all the (formerly Relay) stations will 
>also repeat the packet.  Won't that cause more
>collisions and lower the probability that the packet from 
>the balloon makes it to the I-gate?

Its a judgement call.  Most "relay" digis (to be WIDE1-1)
digis cover such a small percentage of area (id guess
1 to 5%) they are a very small issue.  But if you land next
to one, it may be your only chance to find it.  So *doing*
it gives you a 1 to 5% finding advantage.

Now the QRM is also a judgemnet call.  But remember that
all the digis AND "wide1-1-only" digis will all key up at the
same time.  And so the IGate will hear the DIGI that it is
closest to and will only hear QRM if it is next to a wide1-1-only
digi.  That probabiliyt is also down in the 1 to 5% range?

Hence they appear to be equal benefit versus liability...

But not every packet will have a perfect collision.  Thus
some will get through because the digi may be delayed
by other QRM on the channel so the two dont collide.

Thus the 1-to 5% benefit (always) slightly is better than
the 1-to-5% liability (sometimes)...  And the beneift of
the former lets you FIND the payload, where as the
liability of getting to FINDU is just a nice to have if
lost...

Or at least that is my thinking.  But remember, tonight's
brilliant idea is the realization that WIDE2-2 or even
WIDE3-3 is no worse than WIDE in the air, but then
becomnes a 2 hop or 3 hop path on the ground...

Now, that being said, now you have to decide if you
want to bother with the WIDE1-1 only digis and use
the WIDE1-1,WIDE2-1 path for the slight probability
that you land next to a WIDE1-1-onlydigi.

I guess, having said all that, I'm now leaning away from
encouraging WIDE1-1 and triggering all that TVI just
for the minuscule advantage.  Therefore, why dont we
say WIDE2-2 or so for balloons?  Eveyone wins? and
its no worse than the old WIDE.?
Bob

S

Russ   KB0TVJ

-----Original Message-----
From: Robert Bruninga [mailto:bruninga at usna.edu] 
Sent: Monday, April 04, 2005 12:34 PM
To: russ at wxqa.com 
Cc: hanksn at aol.com; manes at attglobal.net; mgriffin at centrosystems.com;
n0ndm at comcast.net; rick at fastmail.us; Robert Bruninga;
mmccaslin at worldnet.att.net; kb0yrz at yahoo.com; wocbh at yahoo.com 
Subject: RE: [aprssig] BALLOON unproto paths


Russ,

If we are successful with the APRS New n-N Paradigm
in getting rid of RELAY and WIDE in the USA, this will
impact Balloons where we have always recommended
the use of the single hop path of WIDE.

So maybe its time to start shifting the Balooner's over
to the use of the equivalent  which is now WIDE1-1.
The advantage of WIDE1-1 is that it will be digipeated
by fringe area FILL-IN digis as well.

And it works now.  So you can  begin transitioning
over your Balloon receommendations now.

Let me know if you see any problems with this...
Bob, WB4APR







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