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[aprssig] Fill vs. wide?

Cap Pennell cap at cruzio.com
Fri Jul 16 05:37:56 UTC 2010


Unfortunately, there around Temple TX (as elsewhere), there are stations
still set with archaic VHF digipaths (using RELAY and WIDE) that will not
invite operation of any modern APRS digipeaters.  And there are stations set
with no VHF digipath (Direct only), and stations set with a digipath
intended to avoid operation of any fill-in digis (only WIDE2-1).  Looks like
nobody's much watching the local VHF packets at all, nor much helping each
other update their VHF settings, perhaps because so many IGates are all
working nearby.  Digipeaters, who needs 'em?  <grin>  So now, is it likely
that local folks will suddenly effectively _switch_ to watching APRS on VHF
when the internet quits?  Which digipaths will they use to trade local
information on APRS then?  <grin> 

However, nearby stations now using the standard routine (North American, at
least) mobile WIDE1-1,WIDE2-1 digipath are already successfully using the
KE5C-15 fill-in digi, and their packets are then already being heard by a
high full (WIDEn-N/TXn-N) digi, and then by a distant IGate.  From what I
can see from here on internet only, it looks like there's already very
adequate, quite good, VHF digi coverage for your local APRS users who are
courteously paying attention to their VHF transmissions.

Of course, we assume any regular fill-in digi operator already knows which
other digis (and IGates) do routinely hear his digi's transmissions (and
from which specific neighborhood areas travelers actually do need use of his
fill-in digi) as is a needed part of any good permanent digi setup process.
We know some path redundancy may be useful in case of emergency, but too
many digis serving a area will only discourteously reduce VHF network
throughput. 

Remember too, APRS internet displays only show us _the first copy_ of any
VHF packet heard.  Very often, there are many more copies of the packet
flying around on VHF too, consuming more of the limited available airtime we
must all share, but all those extra copies (dupes on VHF) do not show up at
all on the internet display.

KISS?  Not exactly, sorry.  Effective work to improve VHF APRS network
infrastructure (with digipeaters) does start with some considerate analysis
of the existing local VHF network topology. 
73, Cap KE6AFE

P.S.  But when we VHF packet users lose the internet, I hope there is RMS
Relay software running alongside RMS Packet at each of our generous server
stations, so we won't lose our local VHF packet messaging capability.
<grin>  The new ham client messaging software, RMS Express (for MS Windows),
can use a old VHF packet TNC too, as well as internet or it's new soundcard
protocol on HF.

> -----Original Message-----
> From: aprssig-bounces at tapr.org [mailto:aprssig-bounces at tapr.org] On
> Behalf Of John Dvoracek
> Sent: Thursday, July 15, 2010 1:14 PM
> To: aprssig at tapr.org
> Subject: Re: [aprssig] Fill vs. wide?
> 
> You're preaching to the choir. These are all IGates primarily, and
> they typically digipeat about 5% of the packets they hear, at least
> when the internet connection is up.  However, they are located at
> repeater sites with emergency power, and the e-types all say, what
> happens when we lose the internet?  In that case, they can only
> function as digipeaters, hence, my original question.
> 
> http://k5ctx.dstargateway.org:14500/ - for example (doesn't have much
> history as I did a restart for a confg change)
> 
> 73--John
> 
> -----Original Message-----
> Re: [aprssig] Fill vs. wide?
> 
> Conservatively assess the _unmet_ VHF needs of fellow actual APRS users
> on
> the air in the potential coverage area, and cooperatively work backward
> from
> there to improve the VHF network.  Who truly needs (what) more VHF
> packets
> on the channel we all must share?  When?  From where?  Why?
> 
> For those viewing our stuff on internet, coverage is more a matter of
> IGates
> than VHF digis.
> 
> Conservative VHF user settings (of digipath and transmission interval)
> are
> courteous VHF network settings.
> 73, Cap
> 
> 
> > -----Original Message-----
> > Subject: [aprssig] Fill vs. wide?
> >
> > I've searched and found no guidelines although such surely exist, but
> > what's the rule of thumb for when a digipeater graduates from a fill
> > digipeater to a wide-area digipeater?  Is there an antenna height
> > about ground-level criteria?  I sysop digipeaters that vary from 90
> > feet to 400 feet above ground.  There could be all sorts of other
> > criteria I know, but, please, KISS mode reply!
> >
> > 73-John




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