BBSNOTES.txt 7.2        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 one minute random  timer and respond sometime
in the next minute 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 
within 10 seconds or so, 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.  By allowing APRS
stations to see mail lists without even logging on, you are helping reduce
congestion on the channel.   Be sure the BEACON is transmitted to one of the
standard addresses that APRS parses: BEACON, APRS, ID, CQ, QST, etc..


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!  This service can even be made in real-
time for Land Line BBS's.  This allows someone to remotely phone in and
get the full APRS tactical picture.  A simple capture buffer for the last
80 to 150 packets heard would do it.  The best algorithm would save only 
the last 160 UNIQUE packets heard on the APRS frequency.  This buffer only
needs to be retained in RAM, since it is real time...


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!  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 @ WB3V.MD.USA                    Send command with Routing
Subj:    APRS Posit
Msg:     !3858.11N/07629.11W/040/010/Be home at 1200 Saturday.               
         /EX

On receipt of such a message, the receiving BBS (WB3V) would form an APRS
station reporting UI frame and transmit it periodically as follows:

WB3V>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.


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!

