Order Tray | Contact Us | Home | SIG Lists

[aprssig] Infrastructure Question

John Ronan aprssig at ei7ig.org
Thu Mar 31 14:50:00 UTC 2005

Afternoon folks,

We have progressed a bit now in our infrastructure here in the South of 
Ireland and I'd like opinions on something. (I love the way everyone 
here has an opinion :) )

We now have a main Igate/Digi EI3RCW-2 and a backup EI2WRC-3 at 
another, slightly elevated, site.  Both of these are currently also 
responding to the RELAY alias, EI2WRC-3 is using javaAPRSserver do to 
it and EI3RCW-2 is using Digined (satellite tracking is cool).

EI2WRC-1 is a dumb PK12 TNC up high (relatively speaking) and hence our 
WIDE digipeater, this is configured to respond to RELAY and WIDE2-2.

I now appreciate how the network can become congested, as, if I am 
positioned correctly I can be heard by all three digis  which then 
generate two packets addressed to WIDE2-2 (EI2WRC-1 cannot hear itself 
obviously). This can generate up to 5 packets for the single one I 

We plan to add one or two more 'dumb' digi's, so, thinking out loud, I 
would make these RELAY only, and in time, we replace our WIDE2-2 dumb 
digi on MT leinster with a Compact Flash based Linux box running as an 
IGate (we have network connectivity up there on a 5.8Ghz Wireless 
link). Instantly then we should be able to use the smarts of the linux 
box to do some intelligent processing and reduce the channel load (I 
use load lightly as we don't have a whole pile of users, but that will 
hopefully chance over time).

We then have a universal path of RELAY,WIDE2-2 throughout the South 
East, and when our one and only 'Wide' Digipeater gets a bit smarter, 
we reduce the load on the channel.

Is there any firmware out there that could make either a Tiny-2 or a 
PK12 less 'dumb'. As if they could deal with WIDE2-2 in an intelligent 
manner, we could replace those at the same time as making EI2WRC-1 
smarter as well, and have a universal WIDE2-2 path.

Hmmmm, it wouldn't matter all that much though as EI2WRC-1, being 
converted an IGate as well as the 'WIDE' digi would only need to hear 
all the other Digi's and the packets would make it to findu. So most 
likely leaving the 'dumb' Digi's set to WIDE2-2 would work fine.

Just some thoughts, hoping to elicit some enlightened responses (can 
you tell I'm not interested in work today ;) ).

Lastly, we are planning to use APRS in the galtee mountains this 
weekend to support a walking festival, hopefully it will prove useful 
to the organisers.

de John

John Ronan <jronan at tssg dot org>, +353-51-302938
Telecommunications Software &  Systems Group,  http://www.tssg.org

More information about the aprssig mailing list