[aprssig] APRS Cron Object Injector

KF4LVZ aprssigZbr6 at acarver.net
Mon Mar 23 02:42:40 CDT 2015


On 2015-03-22 20:55, Kenneth Finnegan wrote:
> On Sun, Mar 22, 2015 at 7:55 PM, KF4LVZ <aprssigZbr6 at acarver.net> wrote:
>> For any user that does need regularity in the beacon (without a random
>> delay)
> 
> Why would users want regularity in APRS-IS beaconing? My script still
> ensures that the average interval is exactly what the user specifies,
> so what is the advantage of hammering the APRS network on the top of
> any minute? APRS channel access depends on being a stochastic process;
> based on the original Abramson AHOLA models, introducing entropy
> should improve overall APRS network performance.

Well regularity can be useful for timed beacons (e.g. a propagation
study) when the transmission has to occur at the same time whether or
not it makes it through.  The point is to not discount the possibility
to have perfectly regular but offset beacons.


> I mentioned dithering in section 7.1.4 of my thesis, but sadly didn't
> have the time to expand on the evidence I had collected showing the
> poor level of entropy on the current network. Congestion on the
> network collects around even intervals, even while the channel is
> relatively empty. http://digitalcommons.calpoly.edu/theses/1341/
> 
> This is a minimalistic solution. Why should users be depended upon to
> correctly pick a random offset themselves? That's what the current
> scripts depend upon, and users keep picking zero.  By the time they
> have the understanding to properly offset their beacons, I would hope
> they're no longer using a cron job to beacon their objects.

That's a problem with education rather than technology.  People pick
zero because they just don't learn or don't want to learn.  But not
using a cron job for a beacon is a bit odd considering that a beacon is
a regular event and a cron job is exactly what you use for a regular
event (regardless of the randomization you added to the script inside
the cron job).


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