APRS/AVL at Wildflower Triathlons 2002
Updated: 29 April 2002
|
Acronyms and Definitions |
|
|
Overview of APRS |
|
For general information on APRS, check the pages at the Tucson Amateur Packet Radio (TAPR) site. They have a special interest group (SIG) on APRS known as the APRS Special Interest Group (APRS SIG). They also have an email list for APRS Announcements and News which is worth reading. The TAPR site also has an archive of the APRS Announcements and News. Many questions on APRS have already been asked and responded to. Click here to go to the
TAPR home page. |
|
Overview of APRS at Wildflower |
|
Purpose |
|
The primary purpose of using APRS and AVL at Wildflower is to provide an automated map display with the position of chase and rover units for use by the dispatcher. Automatic reporting of position reduces the amount of radio traffic on the voice channels and also provides a confirmation of unit position during an emergency (such as an accident). The Wildflower 2002 Dispatch Team will be responsible for the MacAPRS node at the dispatch center at the San Antonio Lake Vistor Center at the intersection of San Antonio Road and Lynch Road. |
|
|
|
History |
|
2002 is the sixth year AVL will be used at the Wildflower Triathlons. |
|
|
|
Mobile Trackers |
|
Equipment in mobile units (known as a tracker) will periodically determine the unit's location (latitude and longitude, optionally course and speed) and transmit it via the 144.39 APRS digipeater network. The latitude and longitude is typically determined by a Global Positioning System (GPS) receiver located in the vehicle. |
|
|
|
Digipeaters |
|
The N6CP-1 APRS Digipeater on Williams Hill will be used to link the mobile trackers to the Wildflower Dispatch Center at the San Antonio Lake Visitor's Center (they may also be heard directly at the dispatch center, depending upon their location). |
|
|
|
Dispatch Map Display |
|
A map display (using MacAPRS) will be set up at the Wildflower Dispatch Center for use by dispatch personnel. It will display the mobile units' reported position overlaid onto a map of the Wildflower course and roads. Click
here for an example of the wide-area map.. |
|
Details |
|
N6CP-1 Williams Hill APRS Digipeater |
|
The N6CP-1 APRS Digipeater is permanently installed on Williams Hill, overlooking San Antonio Lake, just north of Jolon Road. This digipeater should be able to hear a 20 watt mobile with an external antenna over almost all of the Wildflower course. There may be short gaps in coverage. |
|
|
|
Mobile Trackers |
|
Mobile trackers using an HT or other low power transmitter may not be heard on all of the course, but coverage should be adequate. All chase and rover units should have at least 20 watts. The path should be RELAY,WIDE3-3 when travelling to the lake. Units should generally be visible at dispatch when they leave home to travel to the lake. Once at the lake, a path of N6CP-1 should be adequate. Since each station will send its position every couple of minutes, a longer path should be avoided during the event. All Wildflower communications personnel with mobile trackers must have their equipment working prior to leaving for the lake. N6NL will be checking the operation of each unit on Friday evening. Any units which he determines to be improperly configured or have other problems should be taken out of service if the problem is not fixed to his satisfaction that evening. |
|
|
|
TNC |
|
Kantronics KPC-3 and KPC-3+ are the recommended Terminal Node Controllers (TNC) for use in building mobile trackers. Click here for Jeff Brenton's tutorial on configuring a KPC3+ V8.3 as a dual-mode tracker There are also several other options for trackers. TinyTrack II information and software Still seeking info for Kenwood TM-D700A configurations. |
|
|
|
NMEA Sentences |
|
$GPRMC is the recommended NMEA (National Marine Electronics Association) sentence to be used to report position. If your GPS does not support this sentence, then $GPGLL is the recommended alternative $GPRMC is the "Recommended Minimum Specific GPS/Transit Data" sentence. The format of the $GPRMC sentence is: $GPRMC,hhmmss.ss,a,ddmm.mmmm,n,dddmm.mmmm,w, |
|
hhmmdd.ss |
UTC of position fix |
|
|
a |
status |
a = valid, v = invalid |
|
ddmm.mmmm |
latitude |
degrees, minutes and |
|
n |
direction |
N = north, S = south |
|
dddmm.mmmm |
longitude |
degrees, minutes, |
|
w |
direction |
E = east, W = west |
|
z.z |
speed over ground |
knots |
|
y.y |
rack made good |
Degrees from True North |
|
ddmmyy |
UTC date of position fix |
|
|
d.d |
Magnetic variation |
degrees |
|
v |
Variation |
E = east, W = West |
|
CC |
Checksum |
|
|
|
|
Testing |
|
If you are in the SLO area, use the path KD6DSI-5,WIDE3-3 while testing. This should be sufficent to have your packets arrive at one of the nearby Internet gateways. Do not forget to reset your path to RELAY,WIDE3-3 before leaving for the lake. Once again, during the event, we will be using only N6CP-1 in the path to reduce congestion outside of the area. |
|
Advanced Features |
|
Software for map display |
|
If you want to be able to see others in the event, you will need APRS map display software, such as WinAPRS, MacAPRS, javAPRS, APRS+SA, PocketAPRS/palmAPRS, Xastir and XAPRS. |
|
|
|
Maps and Labels |
|
For WinAPRS and MacAPRS, N6NL has developed map and object label files. The following map file should be put in the Maps subdirectory and renamed from Wildflower_map.bin to Wildflower.map.
The following label files should be put in the Labels subdirectory. |
|
|
|
Wildflower Units |
Position assignments have been made by the Dispatch Team.
Position assignment specifics will be coming soon.
|
Callsign |
Tactical |
To Call |
Symbol |
Freq |
Oper |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
End of document. Send comments to change@nightwind.net