Kenwood TM-255A Product Manual

Also see for TM-255A: Instruction manual Instruction manual Service manual Instruction manual Instruction manual

Contents

7 APRS NETWORKSTM-D710A/E CONTENTS 37UIDIGIUIDIGI: ONALIAS: SAR(other local paths can be defined here)Note: SAR stands for “Search and Rescue”.UIFLOODUIFLOOD: ONALIAS: SS or SSSSUBSTITUTION: ID(where SS or SSS is the abbreviation of state or ARRL section)UITRACEUITRACE: ONALIAS: WIDE7.4.5 Proper Configuration (written by Bob Bruninga, WB4APR)New-N Paradigm recommends three major routing paths. The most important is the NationalStandard of WIDEn-N (usually 2-2). It should always be used for routine operations. Howeverthere 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 drillsor for emergencies. During these periods, it is desirable to have all APRS participants over thestate or section area to be able to communicate among each other. In some states, this may takemore than a 2-hop path. But using more than 2 hops also causes many packets to go outside ofthe 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 mechanismcan be used. For example, using WIDE3-3 from the middle of Maryland would reach alldigipeaters in Maryland, but someone in the far west or far southeast would need 5 hops. Butsuch a 5-hop path would cause QRM over 13 states! However, by using the state routing path ofMD5-5, the sender’s packets will go a full 5 hops in Maryland, but will not go into any adjoiningstates. In fact, for the user in the center that only needs 3 hops, it does not make any difference touse 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 andTM-D710A/E mobile transceivers. These transceivers can all be used as backup emergencydigipeaters in support of special needs. All mobiles should be programmed to act as digipeatersfor TEMPn-N packets. In this way, these mobiles are always ready and enabled to act asdigipeaters for this special path but, on the other hand, they do not digipeat any other packets sothey 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 beable to get out by hopping mobile to mobile.To further benefit this alternate backup digipeating technique, some special battery-poweredbackup digipeaters at high locations can also support this path.