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22876RE: [aprsisce] Strange path for repeater object.

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  • Tony VE6MVP
    May 10, 2013
      At 05:00 PM 2013-05-10, Robert Bruninga wrote:

      Given that you suggest sourcing the packets at each of the four digipeaters around that repeater object in question makes a lot more sense.  I must admit I was thinking in terms of only the single "closest" digi to the repeater.   Blind spot on my part.   <smile>   And when I review your web page I'm thinking you might want to add a sentence along those lines.   My conceited attitude is that if I miss something other folks likely will be missing the same concept.

      BTW the digis in question are up to 30 or 40 kms from the repeater object.

      I'll talk to the folks who run those digis and we'll see what we can do.

      Tony



       

      Tony,

       

      Thanks for the very informative info.  But I fear this technique sets  bad example…

       

      > Therefore, in my opinion, some objects such as repeater objects,

      > should be one hop digipeated by the various digipeaters around the object.

       

      We agree completely in ever digi putting out the info, but every DIGi should source this info, and most digipeaters have BEACON room for 2 or 3 of them.  And I do like to see this local info…, but the objects should be “sourced” by those 4 digipeaters with a direct path (no hops) so that the DIGI only transmits them when the channel is clear.  Only the digipeaters can hear their “input area” and so only they can add this info to the channel so  they do not  collide with any user packets at all.

       

      Sourcing them at one place and having them bounce around to all 4 digis takes up 5 times as much channel capacity.  And none of those packets are guaranteed not to collide with user packets.  But if they are –sourced- at the digi, then the collision potential is zero.

       

      > The path VERMLN,LLOYD,PROVST,ALIANC is for repeater object 145.29-RW

       

      Again, that is 5 times the channel QRM compared to the way these objects are supposed to be designed so that they have zero impact on users by having no path and being sourced at each digi.

       

      >  So basically the packets are travelling in a ring or box   around the repeater.

      But that is the worst possible method generating 5 times the channel load.  The total amount of QRM being generated is as if these beacons were every 2 minutes if you count the total time slots involved.  When sourced at the digis, the time slots count is actually ZERO since the digis will only originate the packet (no hops) when the channel is clear.  So although I keep saying it is 5 times larger, it is really infinitely larger QRM because 5 times larger than nothing is infinite.

       

      > Also we have a very lightly loaded network out here…

       

      True, but it sets a bad example and these things tend to get entrenched and hard to correct later.

       

      Thanks for putting out this info.  I wish more people did it.  But I worry that this is setting a bad example.  My web page that describes all this is on http://aprs.org/localinfo.html

       

      Hope that helps…

       

      Thanks,

      Bob, Wb4APR
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