Kenwood TM-255A User Manual

Page of 100
7 APRS NETWORKS
TM-D710A/E
37
UIDIGI
UIDIGI: ON
ALIAS: SAR 
(other local paths can be defined here)
Note: SAR stands for “Search and Rescue”.
UIFLOOD
UIFLOOD: ON
ALIAS: SS or SSS
SUBSTITUTION: ID
(where SS or SSS is the abbreviation of state or ARRL section)
UITRACE
UITRACE: ON
ALIAS: WIDE
7.4.5 Proper Configuration (written by Bob Bruninga, WB4APR)
New-N Paradigm recommends three major routing paths.  The most important is the National 
Standard of WIDEn-N (usually 2-2).  It should always be used for routine operations.  However 
there are two other possible network arrangements for special situations: SSn-N and TEMPn-N.
SSn-N is for state or ARRL section communication special nets.  These nets are called up for drills 
or for emergencies.  During these periods, it is desirable to have all APRS participants over the 
state or section area to be able to communicate among each other.  In some states, this may take 
more than a 2-hop path.  But using more than 2 hops also causes many packets to go outside of 
the state and to add QRM in adjacent areas which is poor operating practice.
To allow longer hops within the state or section for these events, the SSn-N routing mechanism 
can be used.  For example, using WIDE3-3 from the middle of Maryland would reach all 
digipeaters in Maryland, but someone in the far west or far southeast would need 5 hops.  But 
such a 5-hop path would cause QRM over 13 states!  However, by using the state routing path of 
MD5-5, the sender’s packets will go a full 5 hops in Maryland, but will not go into any adjoining 
states.  In fact, for the user in the center that only needs 3 hops, it does not make any difference to 
use MD5-5 or MD3-3, because in either case, his packets will hit all the digipeaters in Maryland.  
So for state-wide drills, the recommended path is MD5-5 for all participants anywhere in the state.
The TEMPn-N system is an emergency backup system that is inherent in all TM-D700A/E and 
TM-D710A/E mobile transceivers.  These transceivers can all be used as backup emergency 
digipeaters in support of special needs.  All mobiles should be programmed to act as digipeaters 
for TEMPn-N packets.  In this way, these mobiles are always ready and enabled to act as 
digipeaters for this special path but, on the other hand, they do not digipeat any other packets so 
they do not add any QRM to normal operations (using WIDEn-N or SSn-N).  But at any time, 
someone in a valley, or after digipeaters are lost in an emergency, the path of TEMPn-N might be 
able to get out by hopping mobile to mobile.
To further benefit this alternate backup digipeating technique, some special battery-powered 
backup digipeaters at high locations can also support this path.