[aprssig] Newbie APRS object question

Keith VE7GDH ve7gdh at rac.ca
Fri May 22 12:47:15 EDT 2009

Wes AI4PX wrote...

> In general , yes sending this objects from an IGATE would not be
> desireable.

I'll go along with the "in general" but think of the many IRLP nodes
that run the IRLP to APRS status script. If their local IGate didn't
gate them out onto RF, mobile travellers wouldn't be able to see them.

> I wouldn't go so far as to say bad, but... you have no control of the
> path the IGate uses, so your packet would cover an area wider that you
> expect / want / need. Also, more than one IGate might send your packet
> and lastly, the IGate would encapsulate your packet inside it's own
> and make the original packet longer on the air.

That is correct. The IGate operator would have control over the path.
They would also have control over what they gate. Gating messages to
local stations should be automatic. Only chosen specific objects would
be gated, like the local IRLP node. My IRLP node also generates an
object for the weekly coffee get-together by the local club and my IGate
gates it (one hop) to RF.

Fred - you can generate as many objects as you want and send to the
APRS-IS. You might get someone's attention if they were frivolous, but
they can't hurt anything there. On RF, bandwidth is limited. In the case
of a repeater object, it should only be seen on RF in the immediate
vicinity of the repeater where it can be useful. That is why it's best
for the local digi to send it out, direct with no hops. As Bob mentions,
the digi usually hears more because it is usually higher. There will
occasionally be "perfect doubles" but it will only beacon the object 
when the frequency is clear as far as it is concerned.

You can generate your object and send it to the APRS-IS and do no harm.
However, for the best utilization on RF, look around to see if you can
find the ideal digi to send it and contact the operator. It should only
be sent from your location on RF if there are no other choices, and even
then direct or one hop at the once, and if the frequency is busy there,
really try hard to find a local digi operator to generate it instead of

73 es cul - Keith VE7GDH
"I may be lost, but I know exactly where I am!"

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