[OZAPRS] APRS on 30 metres HF (Robert Bruninga)

Fri Feb 9 09:12:00 EST 2007

> Yes, I understand the importance of the path length limit, 
> but why  WIDE1-1?  Why not WIDE2-1?  ...GATE,WIDE1-1 is 
> the same as GATE,RELAY in the old setup.  GATE,WIDE2-1 is 
> the same as GATE,WIDE.

You are entirely correct.

> ... a frame is addressed to GATE,WIDE1-1 will activate 2 
> extra local fill-ins unnecessarily, as well as all the 
> WIDEn-N's, doing nothing at all to help the frame get to 
> an IGate, and wasting valuable air time. 

You are correct here as well.  And correct that either solution
has advantages and disadvantages.  So let me try to explain my
thinking.  Either answer might be right, but I think we need one
answer so that things remain simple for all.  I'll number the
points to keep track of the ideas.  And you are right that most
of these poitns can go either way too...

1) Since this is HF, the path recommendation is not a local
thing, but will affect everyone everywhere.  Thus, we don't want
multiple regional recommendations.  We want -one- that works
everwyhere

2) Your comaprison of GATE,WIDE1-1 to GATE,RELAY is correct,
except for a subtle change that has evolved.  Back when APRS ws
first introduced, -every- home station was expected to be a
RELAY, but now with the change to WIDE1-1 for fill-in-digi's
only, it is not every home station that is impacted, but only
those special fill-in digis which are much-much less numerous
than the old RELAY concept.  In your example, only 2 are
affected.

3) I am surprised that your local GATE can hit all of the local
WIDEn-N and both of the 2 WIDE1-1 digis directly.  In that case,
the local fix is to reduce the power of the HF gate so that it
doesn't hit the WIDE1-1's, and hits only the WIDEn-N's.  A local
fix to a local problem.

3) I suggested GATE,WIDE1-1, because it will go thorugh any
remote GATE that may only have a local WIDE1-1 to get it to the
nearest Igate.  Whereas using GATE,WIDE2-1 would not make it
through those few wilderness Igates.

4) Another reason is that I get tired of always having to
explain that WIDE2-1 is the same as WIDE1-1, and so by
receommending GATE,WIDE1-1, everyone can easily see that it is
only 1 hop on VHF.  See reason #1

5) Packets originated as GATE,WIDE2-1 arrive as GATE,DIGI,WIDE2*
and this implies that the originator took two hops on VHF in
violation of the receommendations.  When in fact he sent WIDE2-1
properly.  But the two are indistinguishible on receipt, so why
put everyone at risk of self-policing doo-gooders.  If we
recommend GATE,WIDE1-1 then they all arrive as GATE,DIGI,WIDE1*
and everyone is happy and can prove they did it right.

So when I added up all the pro's and con's, I came up with the
conclusion that GATE,WIDE1-1 looked the best for recommending
universally.. Mostly due to the unresolvable problem of #5

> So, if keeping traffic low is the number one rule, 
> then why are we advertising a path that increases it  
> needlessly?

Actually, it does not increase traffic:

A) all digipeats of a packet should all occur at the same time
so that no additional time slots are used no matter whether it
is a WIDE1-1 or a WIDE2-1.

B) Letting all HF packets arrive on VHF as GATE,WIDE2* even
though only 1 hop was used might be easily missinterpreted as
GATE,WIDE2-2, and so it migh tactually encourage the use of the
wrong path and cause increased load unintentionally...

Just my thoughts.
Bob, Wb4APR

> On Fri, 09 Feb 2007 01:29:55 +1100, Robert Bruninga 
> <bruninga at usna.edu>  
> wrote:
> 
> >> Why WIDE1-1?
> >
> > See HF.TXT.
> >
> > Because all HF packets in the world using the path of VIA
> > GATE,WIDE1-1, have the potential to enter ALL local VHF
networks
> > all over the world.  This is OK, when they get gated into a
> > local
> > network *locally*.
> >
> > But if those same HF operators use the path of VIA
> > GATE,WIDE2-2, then there are two BIG problems:  1) they
would be
> > multiplying their potential presence in *every* local area
by a
> > factor of 4 to 5 or more everywhere because they would be
> > flooding everywhere.  And 2) the AREA being QRM'ed is no
longer
> > "local" to the GATE doing the flooding, and hence the areas
> > being QRM'ed have no local control over the flood in their
area.
> >
> > It is the number 1 rule in APRS.  Do unto others as you
would
> > have them do unto you.
> >
> > Due to the low bandwidth of the 1200 baud APRS channel, it
is
> > best when local sources of outside area QRM are kept under
Local
> > control.  Hence, the courteous HF operator uses a path no
longer
> > than GATE,WIDE1-1 to keep his packets *local* to the Distant
HF
> > gate that is injecting them into his -local- area.
> >
> > Just makes it courteous to everyone else...
> >
> > Bob, WB4APR
> >
> >
> >
> >> On Thu, 08 Feb 2007 23:55:41 +1100, Radio
<radio at dodo.com.au>
> > wrote:
> >>
> >> > Well, I based my original setup on the pages that Tony,
> >> VK5AH quoted in
> >> > good
> >> > faith. Today, I phoned Ross, VK3MY and he suggested GATE,
> >> WIDE1-1 was the
> >> > correct path. I guess there are now conflicting settings
> >> that need to be
> >> > adjusted, to suit a common agreed path setting for  HF
> >> stations on 30
> >> > metres,  that are mobiles etc.
> >> >
> >> > Jack VK4JRC QG56FJ
> >> >
> >> > Tony wrote....
> >> > Snip>
> >> >
> >> > Just isnt true.. Recomending anything with WIDE1-1 isnt
> > allways
> >> > guaranteed
> >> > to get very far either
> >> >
> >> > That might all work nice for you but are we really
expecting
> > the
> >> > Ionosphere
> >> > to work that well that we can make regular use of your HF
> >> gates over
> >> > there
> >> > ?? I think not. By the way we have our own HF gates over
> > here and
> >> > sometimes
> >> > they pick up posit beacons transmitted from your gateways
..
> >> >
> >> > Maybee for the best solution to the question in VK land
> >> have a look at
> >> > this
> >> > web page which isnt all that dated.
> >> > http://www.aprs.net.au/hf_aprs_information.htm
> >> >
> >> >
> >> > Tony Hunt  VK5AH
> >> >
> >> >>
> >> >> Message: 2
> >> >> Date: Wed, 7 Feb 2007 18:39:58 -0500
> >> >> From: "Robert Bruninga" <bruninga at usna.edu>
> >> >> Subject: Re: [OZAPRS] APRS on 30 metres HF
> >> >> To: "'Radio'" <radio at dodo.com.au>, "'VK / ZL  APRS
Users'"
> >> >> <ozaprs at aprs.net.au>
> >> >> Message-ID: <026e01c74b11$473c7460$42577a83 at SGSbb>
> >> >> Content-Type: text/plain; charset="us-ascii"
> >> >>
> >> >> > I have tried several HF path variations like GATE,
> >> >> > WIDE and did not make it to www.findu.com
> >> >> >
> >> >> > What is the correct path statement that should be
used?
> >> >>
> >> >> The path that has always been recommended since we first
> > began
> >> >> HF APRS on that freequency back in 1993, that is, VIA
> >> >> GATE,WIDE1-1.  (it used to be VIA GATE,WIDE, but the
WIDE
> > part
> >> >> of that is now obsolete and will not work).  See the
> > original
> >> >> HF.TXT file.  See the web page:
> >> >>
> >> >> http://www.ew.usna.edu/~bruninga/gates.html
> >> >>
> >> >> Do not use ECHO.  The page explained above tells why...
> >> >>
> >> >> Thanks
> >> >>
> >> >> Bob, Wb4APR
> >> >>
> >> >
> >> > _______________________________________________
> >> > Ozaprs mailing list
> >> > Ozaprs at aprs.net.au
> >> > http://aprs.net.au/mailman/listinfo/ozaprs
> >> > ________________________________________________
> >> >
> >> >
> >> > Dodo - an Official
> >> > Sponsor of the
> >> > 2006 FORMULA 1 (tm)
> >> > Foster's Australian Grand Prix
> >
> > _______________________________________________
> > Ozaprs mailing list
> > Ozaprs at aprs.net.au
> > http://aprs.net.au/mailman/listinfo/ozaprs
> 
> 
> 
> -- 
> Using Opera's revolutionary e-mail client:
http://www.opera.com/mail/
> Send instant messages to your online friends 
> http://au.messenger.yahoo.com 
> 

_______________________________________________
Ozaprs mailing list
Ozaprs at aprs.net.au
http://aprs.net.au/mailman/listinfo/ozaprs
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://second.aprs.net.au/pipermail/ozaprs/attachments/20070209/f64c371f/attachment.htm 