[aprssig] aprssig Digest, Vol 85, Issue 5

[Mike GM1WKR]

Hi Alex,

Thanks for the reply,

I think you may have misinderstood, the netSked spec says "FOr example
"3/30" indicates it will be transmitted every 3 minutes for 30 minutes. " so
it does give transmit interval as well as a duration - I just wanted to
check if the duration applies to the beacon start time or the actual net
start time.  The file at http://www.aprs.org/info/netsked.txt was written in
2008 so I also wanted to check I am looking at the most uptodate spec.

My question regarding the doubling of the rate was one of etiquette and QRM
avoidance, I am very keen to run a nice digi and wished to check that
beaconing an Object at 90 second intervals is OK.

My comment regarding "Weekday", "Weekend" and "Daily" keywords was a only
suggestion to extend Bobs suggested file format - many Nets run daily on
weekdays or on weekend days only rather than once a week or every second
week.

Thanks info re Cron.  I'd prefer to write as a daemon (initially in PHP as
it's all I'm comfortable with and then try porting to C or even java) so it
would be more platform independent.

Cheers
Mike
GM1WKR

> >
> > Hello,
> >
> > I'm attempting to write a net sked engine to squirt some
> > net objects at the
> > local digi and have a few questions (sorry if they are not
> > in context of
> > this list).
> >
> > 1]  Is http://www.aprs.org/info/netsked.txt is
> > the most up-to-date spec for
> > a Net Sked engine
> >
> > 2]  Is Bobs' suggested file format (URI above) now a
> > standard or is it
> > likely to change?
> >
> > 3]  APRS DTI - am I correct it is a plain old Object
> > DTI (semi-colon)?
> >
> > 4]  Beacon Rate ... using the following line as an
> > example
> > tuesday   9:30 PM 3/30 NET-AARC
> > 147.105 none R17m VIA WIDE1-1
> >
> > Does the /30 mean the Net runs for 30 minutes or that the
> > Beacon should run
> > for 30 mins, I'm assuming this is actual Net duration and
> > the engine will
> > start beaconing 10 minutes prior (9.20 PM in the example)?
>
> According to the document that you posted, 3/30 means beacon three times
> every thirty minutes (so once every ten minutes).  Seems like a poor choice
> of format to specify N per M minutes rather than a simple period between
> beacons.  A quick glance doesn't make it easy to figure out the actual rate,
> you have to do a calculation in your head.  But if the field simply had the
> period (say just a 10) that would make a lot more sense (10 minutes between
> packets).
>
> Net duration isn't indicated in the file format at all from what I can see.
>
> > Bob suggests doubling the rate (3 in the above)  ten
> > minutes either side of
> > Net Start time - can I clarify this means a beacon every 90
> > seconds or have
> > I mis-unserstood this bit.
>
> Doubling the rate as listed would mean a beacon every five minutes (since
> he used the format N per M minutes it's 3/30 = 1/10)
>
> > 5]  Could I humbly suggest the keywords "Weekday",
> > "Weekend" and "Daily" be
> > included in the spec as well as 'nth Mon' and 'Teusday'?
>
>
> If you do this in the world of Unix/Linux you have half of what you need
> already by way of the "cron" program.  Cron is very flexible with the date
> and time specification allowing programs to be executed once per day, week,
> month, year or multiple times per day, week, month, or year as you see fit.
>  The cron configuration (a "cron job") could execute a script that would run
> in the background to inject packets onto the air or via the APRS-IS through
> various means.  The script itself then only needs to create the packet and
> transmit it.  Repetition of the beacon can be achieved with the cron
> configuration or internal to the executed script (that's up to the end
> user).
>
>
>
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>
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