Order Tray | Contact Us | Home | SIG Lists

[aprssig] [uidigi] Re: A new APRS paradigm

Stephen H. Smith WA8LMF2 at aol.com
Thu Feb 17 00:38:26 UTC 2005


<<  This was just posted on the UIdigi mailing list.  I think it is 
relevent to the discussions going on here.    SHS   >>

======= PASTE MAILING FROM UI-DIGI Yahoo Group ========




Hello Ron, thank you for the message.

I have read about the discussion about these new ... proposed ... rules 
in the aprssig to avoid the congestion of APRS Network but I have not 
follow all the messages and and read exaclty the conclusions...

Yesterday I've received a message from you and WB4APR:

 >Marco,
 >
 >I'm not sure if you have been following the APRSSIG, but
 >since November we have started a whole New n-N Paradigm
 >to drastically FIX the APRS channel.
 >
 >UIDIGI ROM is a big part of it and we are very thankful for
 >your efforts.  UIDIGI ROMS is just about perfect.  Except
 >for 1 problem and then a few nice-to-haves:

 >1) The problem is that we have developed a scheme for
 >sending out the DIGI's posit packet DIRECT every 10 minutes
 >most of the time, sending it 1 hop once every 30 minutes and
 >then sending it 2 hops once every hour and sending it 3 hops
 >once every 2 hours or so.  We can do this with a cute trick
 >in the KPC-3 using all four BLT's LTPaths and LTEXTS.

 >But it doesnt work that way in UIDIGI ROMS.  If you
 >have time to fix it, then no need to do that trick, but simply
 >do the algorithm directly.     This cuts down on QRM by
 >a really big factor, yet lets locals and visitors see the digi
 >every 10 minutes and distant stations see it less often
 >with less QRN.

 >If you simply want to fix it (its broke, because your timing
 >"offset" does not work like we are trying to use it), then
 >simply fix it, but add us a 4th BLT, LTPATH and LTEXT
 >so we can get the timing right.

 >2) The next thing we would love to have is an "N" limit for
 >WIDEn-N.  We are implementing this in all KCP-3's again
 >with a trick.  We put in WIDE7-7, WIDE6-6, WIDE5-5 into
 >the ALIAS lists and this esentially TRAPS these paths to one
 >hop only with callsign substitution.  Your ROM is grea for this
 >because it has 8 such aliases..  But to be effective, every
 >digi in the coutnry has to do it or someone can start a packet
 >with WIDE7-6 and leak thought.

 >We need an "N" limit that is enforcable.  If N is 3 then a
 >packet will only go 3 hops and stop.  If it tries to enter the
 >network and "n" minus "N" is already 3 then it does not
 >even get digipeated once...

 >I wonder if you have time to look at these things?
 >This New n-N Paradigm is taking off and is really having a
 >very good reduction in QRM.

 >thanks,
 >WB4APR
 >Bob"


Since my first experiments with APRS in the late '90 years ... due 
basically to curiosity ... I have thought that this system ...
I can't call it protocol... is based more on a strange mix between TNC
settings tricks and the gentlemen agreements ... more than real 
comunications protocol rules...

And probably most of the APRS users want only to show their station as 
far as possible ...

I saw the first APRS program probably at Dayton on 1994 or 1995 I can't
remember exactly...  And since on 1999 I've several unused 1200 TNC2 
I've decided to do some test from my mountains sites where now I'm 
experimenting
ham "extreme" WiFi links (about 30km) enjoying speed, computer wan and VoIP
...

Well I have ... probably ... contributed to spread the APRS networks and
culture and ... the chaos... My initial interest was drop down to the 
chaos and I don't have so much interest on it... but since I have some
responsability I want ... I want to try help to fix... but I need some time
... just to restore some things... and my mind!

As I remember I don't have so much space available on the ROM so I need 
to drop some not used features as prempted digipeating or routing based 
on SSID... but I'm not sure if they are still used by someone... Could 
you please help me to make a list of not so useful features?

I want to make a list of droppable feature but... probably someone use
that...

Another problem is with my development system for Z80 hardware that is 
very old and not so user friendly ... and a limited availability of 
1200bd and radio...

In the past I've thought to design a new simple TNC2 replacement ... 
with new hardware base ... but the problem is the "protocol" not the 
speed or other things...

To clone some feature I also bought the first buggy Kenwood THD7 and 
TM-D700 but now I've sell them ... and I have a limited 1200bd hardware 
to make local test... the time to test is more than the code time ... 
and doing it alone is difficult...

Now I can't access to this page 
http://web.usna.navy.mil/~bruninga/aprs/fix14439.html probably it is
offline..

Is there all the conclusion about the new feature or the work is still 
in progress?

And what about KPC's firmware????

Bye

Marco IW3FQG






More information about the aprssig mailing list