TopWare Tools/TOOLS.iso/tools/top1483/gepackt.exe/README.WWN

Text File | 1994-01-03 | 10.8 KB | 167 lines

README.WWN      SUGGESTED USE OF APRS IN THE WATERWAY NET

APRS is the perfect tool for passing informal traffic to an from boats and for
tracking boats underway.  APRS incorporates most of the features that the US
Navy has used for years in their tactical data networks linking all ships
underway.  APRS was designed to operate continuously in the background and
provide connectivity between widely dispersed stations.  It will provide
position and status reporting for all units underway, in near real-time.  I
say near-real-time, because APRS should not be considered a mechanism for
intense keyboard to keyboard conversations; but is ideal for exchanging one-
liners over an extended time frame without having to contend with the problems
of maintaining a CONNECTION.  My experience in using APRS on the Naval Academy
boats on summer cruise, is that with boats transmitting their positions
and status once every 15 minutes, there is over a 90% chance that every boat
will be seen at least once every 4 hours.

PROPOGATION STATISTICS:  A secondary benefit of the redundant beacons is that
it operates like a poor-man's chirp-sounder.  Since APRS keeps statistics on
the number of packets heard from each station over the last 24 hours, this
display can be used to verify HF connectivity between stations throughout the
day.  It's like a free-bee radio check every 15 minutes everywhere!  After
watching APRS statistics for just a day, or so, the daily variations in
propogation conditions to all stations is visible at a glance.  Further
improvements in connectivity is possible by changing frequency bands during
the solar day.  By saving statistics on each band in a different file, the APRS
user can use this data to optimize his connectivity at any time of day or
location.

WATERWAY NET OPERATION:  There is already a national APRS position reporting
network operating on 7.085 and 10.151 LSB.  (Tune 510 Hz higher if you are
operating an AEA PK-232)  All boaters and Recreational Vehicles are welcome!
To see the locations of all stations on the net, tune your TNC to the exact
frequency and monitor for at least 15 minutes.  When you first activate APRS,
it will send out a query to all stations on the network for their positions.
If you are not properly tuned in when this query goes out, most stations might
miss it.  For this reason, APRS has the QUERY command so that you can manually
initiate this ALL-NET APRS Query.  After receipt of a Query, all stations
will set a 4 minute random timer, and will respond sometime in the next four
minutes.  So be patient..  Even without a Query, all stations will transmit
their positions once every 15 minutes...

POSITION REPORTING:  Their are several ways to report  your position into the
APRS network.  First, run APRS and both your position and status will be
reported automatically.  Additionally, your station can send and receive
messages to and from other stations on the net.  If you turn off your PC
computer, APRS places your position report in your TNC BeaconText so that
your TNC will continue to report your last known position once every 15
minutes or so.  This Beacon only contains your Position and words to indicate
that your APRS program is not running.  If you want your TNC to automatically
report your position AND some meaningful status information, you can enter
your LAT/LONG and additional comments manually into your TNC BText before
Quitting APRS.

GPS/LORAN AUTOMATIC REPORTING:  With the optional APRS $9 interface routines,
APRS can report your real-time position automatically.  Simply connnect your
navigation device NMEA-0183 output to your second PC COMM port.  APRS will
insert the NMEA position, course and speed automatically into your APRS
position report.

OBJECT REPORTING:  Since ANY APRS station can report the position of any other
objects, your position can be automatically transmitted into the APRS network
by ANY other station.  Simply make a manual report to a friend or other
waterway net member running APRS.  He can put you on his map so everyone in
the net will see you.  Give your LAT/LONG, course and speed.  You can also
include about 28 characters (36 without Cse/Spd) of additional comments as
desired.   This is a good place to report your Estimated-Time-of-Arrival, etc.
All APRS position reports are time stamped, so that there is no confusion as to
when a report was valid.

DEAD RECKONING:  APRS automatically dead reckons all position reports.  This
causes all stations to see the most realistic positional display.  All
stations that are dead reckoned show up in light blue color and have an
anchor line back to their last actual reported position.  To defeat dead
reckoning and display all stations at their last reported positions, simply
hit Ctrl-D to toggle off dead reckoning.  When moving the cursor to select
stations on the map display be sure to select the actual position, not the
dead reckoned position.

TRACK HISTORIES:  APRS automatically saves all track histories to disk.  To
reduce redundant data, APRS normally filters out all positions from the same
station that are within 80 yards of each other.  This accounts for the random-
ness of the Selective Availability.  This filter can be turned off, so that
all positions (that are not exact duplicates) will be saved.  Fixed stations
will only be saved once per track history file.  These track histories can be
replayed at any time, either from memory or from file.

WEATHER REPORTING:  All stations on the net can be apprised of unusual weather
conditions by any station placing a weather symbol on the map.  Just like
stations, weather symbols will be dead reckoned between reports.  In this
way APRS is ideal for reporting the movements of hurricanes and tropical
storms.  There are over a dozen different weather symbols for this type of
weather reporting.  Secondly, APRS has a $9 optional interface routine for
automatically reporting the wind speed, direction, temperature and rainfall
from the ULTIMETER-II home weather station.  All stations with this interface
show up on the maps as a large blue DOT with a line indicating the wind
direction and speed.  Their position report also includes the temperature and
the rainfall.  Similarly, any station can select to use the Weather station
symbol for his station, and can manually enter his wind speed and direction
for display on the net.

WATERWAY NET OPERATIONS:  It is recommended that all Waterway Net participants
that are HF packet capable begin reporting thier positions on the HF APRS nets.
No changes to the existing voice net on 7068 are required!  Since APRS will
be operating continuously, 24 hours a day, it will provide a reliable and
continuous background reporting of most stations.  This will free up the
voice net for passing of more voice traffic, and for position reports from
non packet stations.  One APRS station should volunteer daily to uplink the
voice position reports into the network from his display by placing them on
his screen as OBJECTS.  Once these reports are being uplinked into the APRS
net, any other APRS station can assume reporting responsibility for that
OBJECT (station) simply by uplinking a later report.  If the original station
uplinking an OBJECT hears a later report, it will update its screen with the
new report and will no longer report on that OBJECT since another station has
taken reporting responsibility for that OBJECT.  This enables stations to
pass off APRS reporting responsibilities and keeps the network from being
dependent on specific full time stations.

WATERWAY NET MESSAGE TRAFFIC:  All APRS stations are able to post a one-line
braodcast message (BEACON) to all stations on the net.  This can be used to
alert all stations or make general announcements.  Secondly, all APRS stations
can send short message lines to any other APRS station on the APRS net.  These
messages lines are ACKed line by line for assured delivery.  These short
messages can be used throughout the day for making schedules for voice
contacts on 7268 without the stations having to listen to the HF frequency all
day.  Since APRS does not use a CONNECTED packet protocol, these short message
lines can be used all day long without the problems of timing out.  After HF
voice operations, stations that are packet equipped can just turn the volume
down and park the HF rig on the APRS frequency instead of turning it off.
This will keep them fully informed and reported without any additional effort.

APRS NET FREQUENCIES:  Since most boaters are using a back-stay or other
non-resonant antenna with an antenna tuner, they have no problems operating the
non-traditional WARC bands.  For this reason, and to avoid all the QRM on
40 meters, I recommend that 10.151 LSB be the primary frequency for the
WaterWay Net position reports.  YES, THIS IS IN THE BAND!  Operating LSB
with 1700 HZ tones makes your radiated enegy centered at 10151 - 1.7 KHz
or 700 Hz inside the band edge.  The radiated energy of an HF packet signal is
down by the required 40dB at the band edge.  Because most HF packeteers have
not done this math, you will find the frequency clean with no other packet
QRM.  If you still are not convinced, just tune to 10.147.6 and operate
USB.  It is the same frequency!  We always speak of 10.151 LSB, however,
since the convention on packet is to always refer to the LSB convention.
(AEA TNC's will tune 510 Hz higher and lower respectively since they use
tones centered at 2210 Hz).

OTHER BANDS:  An APRS reporting frequency should also be established on each
of the higher bands as well.  I have not done this, because both of my HF rigs
are dedicated full time to 7085 and 10151.  I would encourage distant travelers
to stake out additional APRS frequencies on 18 and 24 meters.  I have been
avoiding the QRM on 20 meters, but after seeing all of the fixed station APRS
activity on 10.151 over the Xmas holidays, I now think it would be a good idea
to start an APRS frequency on 20 meters too for just casual playing around with
APRS.   New users could plop there and experiemnt with all the features of APRS
without clogging up the RV and Boaters net on 10.151!

NAVAL ACADEMY APRS NET:  During summers only, the Academy operates an APRS net
on 3 Navy HF frequencies for tracking its 20+ boats on summer cruises.
Serious HF APRS shoreside stations might be useful for assisting the
Academy in passing traffic.  If you are interested, please contact WB4APR.
APRS is also used by the Afloat MARS net for reporting the positions of
all stateside MARS stations on frequency for passing phone patch traffic.
The ships, of course, do not report their positions for security reasons, but
using APRS to show the ships who is listening stateside has proved to be
an excellent APRS application.  For more information on the Navy MARS APRS
afloat net, contact N1BFQ in New Hampshire.