APRS has come a long way since it's first implementation. Unfortunately
the documentation is way behind the technology. Most of the documentation
deals with setting up digipeaters. Not much is said of setting up other
"fixed stations" or the real purpose of APRS which is
a network for
mobile operations.
APRS was never intended to be a system of long distance communication
over RF by fixed stations. Or for operators of fixed stations (digis or
"home" operators), to be seen outside of their local area. Local area being
defined as the coverage of 3 digis. APRS is packet, and packet, by it's
nature, is an extremely inefficient means of communications! Fixed
station operations are expressly for providing RELAY services and monitoring
and reporting of local APRS activity.
Operators must remember that APRS uses RF. And as such has the same
problems as other RF protocols whether it be voice, packet, slow scan tv,
etc. APRS used improperly causes severe QRM for other users of the frequency.
Intentional QRM is ILLEGAL and makes the APRS network all but unusable.
The operator is responsible for any signal transmitted from their station
and need to be responsible when setting up APRS stations. Also, you must
remember that even though your area may not have a lot activity, using
too many digis in your unproto path can cause excessive QRM for hundreds
of miles!
The biggest cause of QRM is the settings of the unproto paths.
Never use WIDE,WIDE,WIDE anywhere in your unproto path.
Never use CALLSIGN,WIDE,WIDE if callsign is also a wide.
Always use real callsigns instead of generic aliases when possible.
Never use RELAY after a WIDE.
Never use more then 3 digis in your unproto path unless it's the only way to hit the main digi in your area.
Always use the newer WIDEn-n protocol if available in your area.
Never use the TRACEn-n protocol except for very special needs
(will explain later in article).
Never set up a WIDE or an IGATE unless approved by the local coordinators.
Not following these does and don'ts can bring much chaos to your area, and possibly for hundreds of miles,
and the wrath of the other local operators!
This applies to ALL fixed stations (digis and home stations). Most areas
have APRS groups that try to maintain sanity in the area. They will be
able to tell you what unproto path to use in that particular area. If there
is not a group in your area, start one.
Another cause of QRM and inefficient operation is not configuring proper
TNC settings such as XMIT DELAY and XMIT LEVELS. Please take time to ensure
all the TNC settings are correct for your setup. Just setting up a station
and 'throwing it on the air' without taking the necessary time to set it
up properly is just poor practice. Do you really want to be known as a
"lid"? Other operators in your area will be glad to help you if your not
sure of how to set up your TNC.
It cannot be expressed too many times that APRS is a network and as
such must be coordinated just like any other type of network to be usable.
Haphazard usage yields haphazard results.
Next:
IGATES, the solution to "long distance" APRS communications.
Jump to:
Explanation of APRS protocols - coming soon?
Conclusion - Coming soon?