[aprssig] A/N Footbal Run is underway!

Curt, WE7U archer at eskimo.com
Fri Dec 5 16:54:10 CST 2008

On Fri, 5 Dec 2008, Robert Bruninga wrote:

> The statement is True... IIIFFF everyone at an event or
> associated with the event exclusively used one of those clients.
> Last time I checked, they accounted for about 4% of all APRS
> users...

I didn't suggest that everyone run one of those clients, I suggested
that the protocol for defining the OVER-THE-AIR be added to the spec
so that everyone would have the capability and everyone would see
the same thing.

I don't see the distinction between a small event or a major
event/disaster scenario here...  If this is made part of the spec
and over time the clients adopt it, sending one message would cause
everyone's displays to adopt the tactical call.  Everyone would see
the same thing.

> 3) Even if 20 years from now we get 90% of a club to use those
> exclusive clinets, then still the last thing one would every
> artificially introduce at a comms event is the potential for
> even 10% of the communicators to be seeing not the same thing
> that everyone else is seeing.

So design for the way you'd like to see things 30 years from now...

> Further, even those with the correct software will see the
> *wrong* callsign until they get updated, and sometimes the only
> posit on a station is one-in-a-hundred, so even then too, you
> may have half the people seeing the wrong thing for a long time
> until the tactical-change-call-packet gets through on RF.

Currently we use the message retransmit algorithm, so it goes out a
bunch of times at an exponential backoff just like messages.

Perhaps the protocol for defining/retransmitting the tactical call
definitions needs to be tweaked a little in that case.  This is a
solveable problem.  Perhaps tactical call definitions could be sent
at a slightly higher rate than messages and/or for a longer time

> Again, I am not denegrating that approach for closed-special
> events, but, In my mind, the solution is for all hardware
> devices with callsigns should be encouraged to make it trivial
> for FIELD-UPDATE with no tools, PC, or devices involved.

Great in theory, impossible in practice.  Most of us don't have the
money (or the desire in some cases) to run D7xxA's/D7A's, so run
other quality hardware/firmware which may not give us the capability
to change things in the field.

We've also seen that getting people to change even D7xx settings for
an event often leads to those stations disappearing off the map for
the duration.  Therefore the switch to setting tactical callsigns on
the fly which has worked 100% for us so far.  The most reliable
approach for us has been to use trackers which are in every day use
(therefore known to work properly) and leave them alone.  We then
define tactical calls over-the-air for them.

> That
> is the only reliable, non ambiguous method for changing tactical
> calls during an event.  That's why we like the PM's in the
> D700's, because the mobile can change the call on the fly, and
> it instantly propogates to everyone of every kind throughout the
> RF and WEB domain.  That is where the emphasis should be made...
> Improved callsign changing in the devices.

Great if people know their rigs well and have them set up properly.
Many do not and can't be depended upon to make changes in the field
when needed.  Others that do know are often busy elsewhere and can't
take time to help them configure their rigs.  It's a time/resource
issue and defining tactical callsigns bypasses it completely.

Curt, WE7U.				archer at eskimo dot com
   Lotto:  A tax on people who are bad at math. - unknown
Windows:  Microsoft's tax on computer illiterates. - WE7U.
The world DOES revolve around me:  I picked the coordinate system!"

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