North Texas Amateur Radio Operators Study The Automated Position Reporting System (APRS)
By Doug MacDonald, W4FH
(Plano, Texas, 8 September 2003) - A total of 123 Radio Amateurs from 46 cities throughout Texas and as far away as Witchita, KS, gathered Saturday 6 September 2003 at the Conference Center at the University of Texas at Dallas Richardson Campus for an all-day workshop on the use of the Automated Position Reporting System (APRS) in ham radio. The Plano Amateur Radio Klub (P.A.R.K.) and the Comet Radio Club of UTD jointly sponsored this activity. The overall coordinator for the event was John Beadles, N500M, who worked closely with Barry A. Goldblatt, WA5KXX, President of P.A.R.K., and Justin McAllister, K5AEA, President of the Comet Amateur Radio Club. The seminar also received wide publicity and support from Roy Rabey, AD5KZ, North Texas Section Manager for the American Radio Relay League (ARRL). The workshop included eighteen presentations, one panel discussion, and one "show and tell" session.
The APRS system was developed by Bob Bruninga, WB4APR, and permits automated position reporting using systems suitable for use in the Amateur Radio bands. The system enjoys wide popularity in the North Texas area, and this region is particularly well supported with wide area digipeaters and stations providing "gating" services to the Internet. The seminar focused on three basic areas - the hardware and radio systems necessary for effective APRS use, the software programs available to hams for employment on APRS, and Operating Practices appropriate for this useful communications system. Seminar attendees were encouraged to bring their own APRS systems to demonstrate to other attendees. Help was available from hardware and software experts to configure and to repair ailing systems.
One of the high points of the event was the presence of Byon Garrabrant, N6BG, of Las Vegas, NV. Byon is the designer of the popular "TinyTrak" and "Tiny Trak3" APRS GPS position encoders, and he provided substantial assistance to amateurs needing help with their units. He also discussed the theory and practice of designing small APRS systems with many different participants throughout the event. Byon's company, Bionics.com, provided two TinyTrak3 units as door prizes. A third door prize was a free copy of UIView32, provided by the author, Roger Barker, G4IDE. UIView32 is one of the most popular APRS presentation and control programs.
Pete Loveall, AE5PL, who currently develops the JAVAAPRS Server software for the world-wide amateur Internet community, made presentations in several areas: "APRS Point, " "APRS in North Texas," "APRS & the Internet," "An Introduction to APRS + SA," and "Introduction to PocketAPRS." John Beadles, N5OOM, in addition to serving as overall coordinator for the event, provided presentations on "APRS Functions for Public Service Events," and "APRS & Digital Map Data." He also hosted the "Tiny Tracker Show and Tell" presentation and chaired a Panel Discussion on "APRS for Special Events" that included John Galvin, N5TIM and Jim Schultz, W5OMG. Gerry Creager, N5GXS, from College Station, TX, presented "An Introduction to GPS Receivers," and "HSMM (802.11b) In Amateur Radio." Tony Campbell, W5ADC, headed a discussion on "APRS Tracker Examples," and teamed up with Andy Vrabel, K5TOE, to present "Configuring TMD-700 and TH-D7 APRS Transceivers." Glenn Frasier, KD5DMG, made presentations on "Configuring AGWPE," "An Introduction to UI-View," and "Weather Tracking with APRS." Justin McAllister, K5AEA, and Jerry Karlovich, KD5OM, teamed up to lead a discussion on "Building and Configuring the TinyTrak3," with able assistance from the unit's designer, Byon Garrabant, N6BG," who came in from Las Vegas, NV to participate in the event. Mark Davis, KD5WIN, presented "An Introduction to WinAPRS/MacAPRS," and Ed Lawrence, WA5SWD, presented useful information on "Antennas and Transmission Lines in APRS." Barry Goldblatt, WA5KXX, President of P.A.R.K. and also of Resource800, Inc., made a presentation on "Battery Usage."
Complete copies of all presentations made at the 2003 North Texas APRS Symposium are available at the following web site: http://www.n5oom.org/2003_nt_APRS_workshop.
A number of issues came out clearly during the day's discussions. These are items that should be considered by all amateurs who make use of the APRS system.
1. APRS via Amateur Radio on RF is a tactical communications system - it is intended for short-range use and to provide relevant information within in a limited area. Long-range RF propagation is neither intended nor desired. Current congestion on the major national APRS frequency (144.390 MHz in the US) places the effectiveness of the entire system at risk if the Amateur Radio community does not employ discipline in path selection and beacon frequency.
2. The Internet provides an extremely useful strategic backbone for worldwide information about local movements and events.
3. In congested areas such as North Texas, coordination is mandatory for the addition of Wide Area digipeaters and I-gates. (Sometimes there can be "too much of a good thing."
4. APRS can be extremely useful in special events and in emergency communication scenarios, but pre-planning, coordination, and practice are required for the communication method's potential to be fully realized. Emergency Coordinators, Net Control Operators, and APRS users need to get together to make sure that each knows the capabilities and limitations involved in employing this medium. Effective use of APRS is definitely an area where "practice makes perfect. "
5. In planning for special events, it is essential to have both a net control station and an APRS Coordinator who work together and plan for both APRS deployment and contingencies.
6. Employment of APRS in special events and emergencies requires that all users test equipment and check parameters beforehand to ensure that it performs as expected on the day.
To enhance the effectiveness of the 144.390 MHz national APRS frequency for all amateurs in North Texas, the following recommendations were presented for the setup and operation of APRS units in this area:
Path Settings and their meaning:
PATH SETTING : Meaning and Placement
RELAY : Should only appear as the FIRST item in the path list. If not placed first, this setting can cause "ping-pong" and increase frequency congestion
WIDE : Should only appear once as the First or Second entry in the path
WIDEn-n : Should only appear once as the First or Second entry in the path [There is rarely any reason to use any setting larger than WIDE2-2 in North Texas]
TRACEn-n : Should be used only temporarily for testing to determine the best path for your station.
GATE : This means, "Gate this packet to HF." Unless there is a reason to send your packets to an HF Gateway, this setting should probably not be used.
NOGATE, RF ONLY : This means, "Do Not Send this Packet to the Internet." Most IGATE software will recognize and honor this request if the operator has selected the option.
TCPIP, TCPXX, qXX : All of these settings are added by gating software when it places a packet on the Internet. These terms should NOT appear in the RF Path. Do Not Use!
Recommended Path Settings for different types of stations:
Type Of Station : Recommended Path Setting
Fixed Stations : Digi, WIDE [Where "Digi" = your nearest wide area digipeater]
Mobile Stations : RELAY, WIDE
Air Mobile Stations : WIDE
Special Event Stations : RELAY
Digipeaters : NONE
Recommended Beacon Rates for different types of stations:
Type of Station : Recommended Beacon Rate
Fixed Stations : No Less than 20 Minutes
Mobile Stations : No Less than 3 Minutes except in unusual situations. [REMEMBER TO SET TO 20 MINUTES OR MORE IF MOTIONSTOPS!}
Air Mobile Stations : No Less than 5 Minutes
Special Event Stations : Usually No Less Than 3 Minutes except under special circumstances
Digipeaters : No less than 20 Minutes
Weather Stations : 10 or 15 Minutes [The National Weather Service collects information every 15 minutes]
[All recommendations taken from "APRS in North Texas," by Pete Loveall, AE5PL. ]
Attendees at the conference included 41 Technician Class licensees, 4 Tech Plus, 23 General, 6 Advanced, 47 Extra Class licensees and 2 non-hams. The average attendee had been an Amateur Radio operator for 15.9 years. Of those responding to the check-in questionnaire, 56 of the attendees already use APRS in some form, while 67 do not and were interested in learning about the mode.
