The K3GJ APRS Page
You have two options to access to my APRS pages.
Screen View: This takes you to a snapshot of my UI-View APRS map
page directly from my APRS computer. This shows you the current stations in southern Maryland and the
"tracks" of some of those mobile units I am actively tracking at the
time. An icon will disappear after 90 minutes of inactivity. This page is set up to automatically refresh every two (2)
minutes. If it doesn't automatically refresh in your browser, just use
your manual browser refresh button.
Page: This takes you to the web server add-in service for
UI-View (the excellent Windows APRS program I utilize). This is a series of web
pages that identify the various stations that my APRS station is hearing and
considerable information that those stations are reporting.
The Automatic Packet Reporting System (APRS), developed by
Bob Bruninga, WB4APR,
allows packet radio to track real-time events. While the packet radio system did
a great job with message and text transfer activity, its use has dropped off
dramatically as a result of the Internet. While packet operations are currently
a very useful resource during emergency operations, Bob saw the opportunity to
further utilize the technology for the graphic display of station and object
locations and movements. Bob developed the groundbreaking APRS DOS program
to actively display APRS objects. Other authors have followed Bob's lead
and developed applications to operate on the Windows operating platform.
The integration of Internet technology with Packet Radio technology has not only
provided a new area of interest for Amateur Radio Operators, but has provided a
very valuable tool for use during emergencies for tracking relief and recovery
APRS has too many features for me to adequately address here. There are
other sites that can
provide these detailed descriptions and capabilities if you are interested.
There are a couple of features that you will find of use as you view my APRS
- Fixed stations: These can be identified by the house,
antenna, or blue circle with "WX" in the center icons. The blue circle
with the "WX" is an APRS weather (wx) station which provides real-time weather
reporting for that location.
- Objects: These can be easily recognized by their blue colored
label. They are locations that are important for others to know about
but do not put out their own APRS position report. For example, you will
see on my screen view "W3SMD" with the Red Cross icon. This is an object
placed to identify the location of the Southern Maryland Chapter Headquarters
of the American Red Cross.
- Mobile stations: These are identified by icons that indicate
motion, like a car, van, truck, tractor trailer, boat, motorcycle, etc.
If they are moving you will see their position change. The red line from
the icon shows the general direction they are moving. If you see a
mobile station with a red circle around it, that is a mobile station that has
been identified to UI-View to "track". You will see the map shift to
follow any "tracked" mobile stations. For selected "tracked" mobile
stations you will also see orange lines that show their route of travel along
with small numbers indicating the order in which their position packets were
- Digipeaters: The yellow stars with a letter in the middle
indicate the locations of a digipeater. A digipeater is a fixed location
high power digital repeater that listens for beacons in their immediate area
and rebroadcast those packets to a larger area using much higher power.
These digipeaters provide the necessary retransmission of packets,
particularly from mobile stations, into a larger regional area, often to other
digipeaters that allows the packet to be heard much further than it would have
just from the source transmitter.
- I-Gates: Some fixed stations have a blue box around them.
This indicates that the station is operating an Internet Gateway (I-Gate).
An I-gate takes position packets it hears over the air (RF) and retransmits
them over the internet through one of the several major APRS servers.
These reports can be monitored by any station connected to any of the servers
since the packets heard are shared among them. This allows some stations
to also operate as "reverse i-gates", taking selected packets from the
Internet and putting them back over the air. For example, my station
takes weather bulletins put out over the Internet by the National Weather
Service Sterling Virginia Office and retransmits them over RF to provide any
local APRS station with the latest weather watches and warnings. These
Internet servers are also source of position reports for the very powerful and
useful Findu system
which allows Internet query for specific stations.
These pages are experimental at this point and any comments you
may have for improvement would be greatly appreciated.