RATS APRS Network

Richmond Amateur Telecommunications Society operates Virginia's largest APRS network, promoting fellowship, best-practices and support for emergency communications.  To ensure everyone has access to the network, and in keeping with good amateur practices, please follow these guidelines for APRS activity:

• Beaconing for mobile stations is 2+ minutes and 20-30+ minutes for fixed stations
• Use the minimum power to reach a digipeater, usually 10 watts in well covered areas, or occasionally 50 watts in remote/poorly covered areas.
• Keep your path to the minimum to reach an IGATE, "WIDE2-2" for Fixed Stations and "WIDE1-1,WIDE2-1" for Mobile Stations

RATS maintains this network through the support of our members, the Virginia Department of Emergency Management/ARCA and generous support from several commercial tower leasing companies. There is always room for more volunteers, more sites and more radios.  Please consider supporting our efforts if you have the time and the resources.

Richmond's APRS network began almost 20 years ago with a digipeater in a hotel elevator shaft.  In a two-year period from 2006 to 2008 the network expanded to become the largest "single operator" APRS network in the state.

APRS Operating Guidelines

The following local operating guidelines have been adopted and users are asked to adhere to the following:

1. Set your DIGIPEATER PATH to "WIDE2-2" for fixed or "WIDE1-1,WIDE2-1" mobile stations.
2. Please do not exceed 1 location-beacon per 3 minutes. Controllers will automatically ignore more location-beacons in excess of every 2 minutes.
3. Enable the "MIC-E" transmission format, this is a compressed beacon format and is more effecient.
4. Limit your output power to 25 watts or less.

Digipeater Operational Guidelines

Already running a digipeater? Contact the Technical Committee and we'll help convert your older controller to the newer APRS standards.

1. High-Gain antenna at a minimum of 100 feet above ground, or any location suitable for a local-coverage VHF repeater
2. Radio with 25-30 watts output
3. Any controller:
   • Commercial solution: USmartDigi digipeater daughterboard for the TNC-X TNC. This is the recommend controller for the APRS.RATS.NET network
   • Linux solution: Linksys NSLU2 or WRT54G device modified for Linux with DIGI_NED software
   • PC solution: Any KISS-mode TNC connected to a PC running DIGI_NED (cygWIN Linux emulator required)
4. Emergency Power (72 hours or more)

Controller Rules for APRS.RATS.NET Nodes

BEACON RATE: 15 minutes (30 for fill-in or smaller coverage nodes)

PATH: WIDE2-1 for major nodes, "direct" for fill-in nodes

No single path may exceed 3 (ie: WIDE3-3) and no path count may exceed 5 (ie: WIDE2-2,WIDE3-3)

Excessive Paths are re-written to WIDE2-2 - IN BETA TEST

Coordinate Blocking of a defined NORTH/SOUTH/EAST/WEST boundary (Geo-Fencing)

Throttling of LAT/LON beacons with intervals of less than 120 seconds (Message Packets are exempted from throttling rule)

No WIDE/RELAY/TRACE allowed