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TH-D72A/E CONTENTS 41
6 OPERATIONAL EXAMPLES OF APRS
While monitoring APRS stations from around the world that may appear on your map, you can easily
send messages to them. An interest is now growing in APRS QSOs where one station may call CQ
looking for responses in the conventional style of a ham contact. Due to the number of characters
being restricted, it can be customary to send short sentences using abbreviated words similar to
operating CW.
Searching for weather information can reveal that even adjacent nearby areas can have dramatically
differing weather patterns. Or, operating outdoors and timing transmissions to coincide with
overhead satellite passes can result in successful satellite communications using only a handheld
transceiver. The opportunities for many activities exist even without installing a fixed station at home.
Below are two APRS operational examples. In USA and Canada, the national APRS frequency is
144.390 MHz.
Incorporating an internal GPS unit, TH-D72A/E permits APRS operations on its own. Needless to
say, it is also suitable for outdoor mobile operations. When traveling outdoors with the handheld
transceiver in hand, you can search for nearby stations with position beacons to exchange text
messages and establish voice contact.
To enjoy APRS operation in unfavorable locations, such as in a building or restaurant, some people
set up the mobile station as a digipeater.
Furthermore, APRS beacons that include latitude, longitude, speed, direction and altitude information
are most suitable for hot-air balloon rides and hang gliding, while the support team usually tracks the
whereabouts of the balloon or glider from the ground.
In these cases, since it is necessary to transmit beacons with shorter intervals than usual, operation
is on a different frequency from normal APRS operations. Some applications such as Google Map
APRS (http://aprs.fi/
) have a function to store the movement trajectory of specified stations and can
be utilized to review the flight of the day or to analyze the trajectory in conjunction with the
meteorological data provided by the nearby weather station.
Also, the following are some other features that increase convenience of text messaging while
moving.
This is a function to return a predefined message such as “Pse QRX. Will return later at 12:35”
automatically when an APRS message is received.
Auto Reply is only for passing along special information to anticipated message senders when the
operator may temporarily not be able to respond. It should not be left on for routine operation in most
cases because it adds unnecessary network load. The sending station will always get an ACK (an
acknowledgment message), and this is sufficient to know that the message was delivered in most
cases.
6.1 Let’s Go Mobile
6.1.1 Overview
6.1.1.1 Automatic Reply Function