BBSNOTES.txt 6.2c        SUGGESTIONS FOR USING PBBS's
                                   and for
               INCLUDING APRS PROTOCOLS IN BBS and NODE SOFTWARE


    One thing we have learned in maintaining an operational APRS net on 145.79,
is that it is very useful for all stations to include in the comment field of
their position report the address of their home BBS!  Then any station on the
APRS frequency immediately learns how to send that station a lengthy packet
message.  If your TNC supports an internal BBS, it is also useful to leave it
on and include its unique address or SSID in your comment field so that others
can send you messages on your PBBS even while you are running APRS!  A few
stations sending keyboard messages into a PBBS on the APRS frequency is not
objectionable since the number of packets are small and at typing speed.  Also,
the PBBS owner then DOES NOT read his mail over the air!  I encourage all
stations to operate their own PBBS maildrops on the APRS frequency; but please
do not use the PBBS's to post messages for others who must read the message
over the air.  All stations should avoid any other general computer to computer
exchanges which would block the frequency for large blocks of time.

    The remainder of this file is intended for BBS SYSOPS and the writers of
BBS and NODE software.  Please consider the following advantages to including
APRS protocols in your station operation.  Since APRS allows stations to see
the network topology in real-time, it is ideal for determining the locations
of all neighboring BBS's and NODES and as a general purpose FREQUENCY
COORDINATION TOOL!  See the file README\FREQCORD.txt.  If BBS's and NODES
simply included either the LAT/LONG or GridSquare in a periodic UI frame, all
users could see where the system is located.  For permanent  sites such as
BBS's and NODES, this beacon could probably be transmitted once every hour or
so.  This !LAT/LONG format can be placed anywhere in the BText.  The exact
format of the UI frame should be as follows:

    BBSXX>APRS:!DDMM.xxN/DDDMM.xxW[PHGxyz/comments as desired to end of line
                                  [this left bracket is the APRS BBS symbol
                                   * see PROTOCOL.txt for exact formats
    BBSXX>APRS:[GRidsq]Comments to end of line
   

    For BBS code writers, this process can be enhanced by making the BBS
respond to APRS Query packets.   On receipt of an APRS Query packet, all
stations on frequency set a two minute random  timer and respond sometime
in the next 2 minutes with their location.  This way, any APRS station can
obtain the location of all stations on the frequency soon after comming on
frequency.  The format of the APRS Query packet is W4XYZ>APRS:?APRS?.  By
including the code in NODE and BBS software to respond to APRS Querys, the
periodicity of the APRS position beacon can easily be set quite infrequently
since stations can request the BBS position at any time.  For those concerned
with physical security, the grid square position report can be used which is
ambiguous to 3 miles or so instead of the LAT/LONG posit accurrate to 60 feet.

MAIL-FOR BEACONS:  Since APRS contains a BEACON parser to capture all BEACONS
heard on frequency, this is an excellent way for stations to capture MAIL-FOR
beacons from BBS's.  APRS stations simply call up their LATEST BEACONS display
and see if there is any mail for them.  For this to work, APRS must see the
MAIL-FOR information on the same line as the packet header.  MAIL-FOR which
is listed on a second line after the header do not show up in the APRS system. 
By allowing APRS stations to see mail lists without even logging on, you are
helping reduce congestion on the channel.  Presently, most stations do not see
MAIL-FOR beacons because they scroll off the screen too rapidly.  APRS grabs
all packets that are TO the following addresses: APRS, BEACON, ID, MAIL,
SKYWRN, CQ, GPS, SPCL, and QST.  APRS retains the last of these heard per
station.  APRS can also be told to monitor all OTHER packets with the
CONTROLS-OTHER command.

     Please play with the APRS software and load some of the backup and
demonstration files included.  I'm sure you will find APRS to be an exciting
new capability for packet radio which can make packet radio much more responsive
in real-time communications.

BBS POSITION DATABASES:  Finally, ambitious code writers could add code in
their BBS's to capture all APRS position reports heard on frequency.  These
reports could be retained in a file and be made available to local users.  One
of these files, if downloaded, can be loaded by APRS users to display the
locations of all stations ever heard on the frequency!  Talk about good
preparations for emergency comms!

BBS FORWARDED POSITION REPORTS:  Since we already have a worldwide packet
network of BBS's which have the ability to forward a packet message anywhere
in the country, I would like to see a standard message format built which would
permit a mobile, roving packet station to report his location back to his home
BBS on a once-a-day type basis.  Imagine that this mobile station simply posts
a message on any nearby BBS which contains his position and the routing for his
home BBS.  That packet message would be forwarded via the normal BBS network
and arrive at the intended destination whereupon the destination BBS would in
turn send out a decaying APRS POSITION beacon reporting that unit's position
even if he was thousands of miles away and on the road!  All of his buddies
(or his wife) would see on their home computers his latest position auto-
matically which was actually relayed through the packet BBS network.  As with
any APRS position report, the beacon periodicity would decay from 10 minutes
to once every few hours as the position report got older.  The format for such
a position report for WB4APR might be as follows:

Send:    SP APRS @ W3IWI.MD.USA                   Send command with Routing
Subj:    !3858.11N/07629.11W/040/010              LAT/LONG/CSE/SPD
Msg:     Be home at 1200 Saturday.                Comment field up to 40 chars
         /EX

On receipt of such a message, the receiving BBS (W3IWI) would form an APRS
station reporting UI frame and transmit it periodically as follows:

W3IWI>APRS:WB4APR   @051937/3858.11N/07629.11W/040/010/Be home at 1200 Saturday

As with all APRS packets, this packet would be transmitted once, then one
minute later, then 2 minutes later, then 4 minutes later and so on.  This
doubling ot the packet period after each transmission decays very repaidly to
only 4 packets in the first 10 minutes, 3 more in the next hour and only 3
more in an entire 24 hours!  This is not such a load!  This would only be 8
packets in the first day and only 1 in the second!  When the period is greater
than 24 hours, the message is deleted from the system. People on the road
reporting home would probably send a new message every 24 hours anyway.


BBS POSITION DATABASE:  Since APRS includes an individual station query
capability, a BBS that has accumulated the position of all of its users, could
respond to such an APRS query with a one time position report for that station
without even logging on.  The APRS query is simply a one line APRS message from
the querying station to the Queried station with the letters "?APRS" in the
first 5 character positions.  A BBS with a callsign data base seeing such a
packet could respond immediately with a position report for that station!
The APRS station would see the position on his map!

