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AE5ME > TECH 04.11.15 20:30l 506 Lines 8820 Bytes #999 (0) @ WW
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Subj: //WL2K APRS Messaging
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Sent: 151104/1819Z 25078@AE5ME.#NEOK.OK.USA.NOAM BPQ1.4.64
Converted from a powerpoint presentation posted at http://tulsadigitalradioclub.blogspot.com/
APRS Messaging / Bulletins
By
Jeff Scoville
President, Tulsa Digital Radio Club
Introduction
•Who is the TDRC?
•What is APRS?
•What is required for APRS?
•What is APRS Messaging?
•Messaging on APRSISCE32
•Why APRS Messaging?
•Questions.
Introduction / Who is TDRC?
•Est. 2013 by Jeff AE5ME and Scott KD5NJR
•Innovation-Experimentation-Education
•Digital Radio
•Engineering – Arduinos and Raspberry Pi
•Tulsa Area
•tulsadigitalradioclub.blogspot.com
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What is APRS ?
•Automatic Packet Reporting System
•Primarily Uses 1200 & 9600 Bps
•Primarily VHF, but others possible
•Protocol for “Reportingö with
Primary use being GPS Data
•Unconnected Protocol
•Supports Messaging
What is APRS ?
•Primary VHF Networks
•North America: 144.390 MHz (Voice
Alert 100.0 Hz CTCSS, mobiles only
please!)
•Europe: 144.800 MHz (Voice Alert
136.5 Hz CTCSS)
What is APRS ?
•Primary VHF Networks
•Russia: 144.800 MHz
•Australia: 145.175 MHz (Voice Alert
91.5 Hz CTCSS)
•New Zealand: 144.575 MHz
•Argentina: 144.930 MHz
What is APRS ?
•Primary VHF Networks
•Uruguay: 144.930 MHz (145.010 MHz
also)
•Japan: 144.640 MHz 9600 baud /
144.660MHz 1200 baud
•South Africa: 144.800 Mhz
What is APRS ?
•Alternative Input VHF Networks
•For low-powered trackers only:
•Many areas: 144.99 MHz
•Western Washington State: 144.35
MHz
What is APRS ?
•UHF Networks
•Europe / Africa (IARU region 1):
-Primary 433.800 MHz (heavy ISM
interference in many countries)
-Secondary 432.500 MHz since 2008
where ISM is too bad on 433.800
(CT08_C5_Rec32)
•Australia (VK): 439.100 MHz 1200
baud (in selected areas)
What is APRS ?
•UHF Networks
•Netherlands (PA): 430.5125 MHz
1200 baud
•Puget Sound, WA: 440.800 MHz 9600
baud
•Kansas / Missouri: 446.175 MHz
1200 baud (primary, with
infrastructure)
What is APRS ?
•UHF Networks
•Kansas / Missouri: 441.175 MHz
1200 baud (secondary / special
event, no infrastructure)
•US Nationwide Proposed: 445.925
(proposed by Bob WB4APR)
•New Zealand (ZL): 432.575 MHz
1200 baud allocated but little usage
What is APRS ?
•Six Meters
•United States (IARU region 2):
-Primary Meteor Scatter: 50.660MHz
9600 baud
-Secondary Meteor Scatter: 50.680MHz
1200 baud
-Washington, DC: 50.620MHz 1200 baud
(shared with PropNet)
-Alabama: 50.640MHz 9600 baud
What is APRS ?
•HF
-10.1476 Mhz 300 baud
•Satellites (consult AMSAT)
What is APRS ?
•What does “Voice Alertö Mean?
-Voice stations (mobile) transmit with
PL tone of 100.0 Hz. on APRS freq.
-Participating APRS stations set tone
squelch on APRS and listen for voice.
-APRS packets are not toned, so they
don’t break squelch/irritate!
-Once stations establish contact, they
quickly change frequency to keep
open for standard APRS traffic.
What is required for APRS?
•Computer (PC or Raspberry PI)
•APRS Software (APRSIS, WinAprs,
Xastir, BPQ32, Dire Wolf)
•TNC/MODEM
-Conventional TNC (KPC-3 etc) OR
-Soundcard modem software (PC uses
AGWPE or UZ7HO /Pi uses Dire Wolf)
•2m Radio
What is APRS Messaging ?
•The portion of the APRS protocol
that handles either station to
station or station to all messages.
•Station to station messages are
typically ACKnowleged.
•Station to all messages are NOT
ACKnowledged, but are transmitted
several times to insure receipt.
APRS Message Packet Format
•MESSAGE: Station to station
messages use the following format,
padding the addressee call with
spaces to a total of nine characters
followed by a colon:
-W3XYZ____:one line message
text......{3 (the {3 is the msg number)
APRS Message Packet Format
•MSG ACK: An ACK is just a message
with the letters ACK# where the # is
the message number (following the
{ character at the end of the line):
-W3XYZ____:ack3
•Once ACK is sent, sending station
STOPS repeating the message.
APRS Bulletin Packet Format
•BULLETINs are simply messages to
the call signs of BLN1, BLN2, ...
BLN#. They will never be ACKed.
They are repeated a number of
times on a fairly long period (20
minutes between retransmit is
typical).
APRS Message Pathing
•Your UNPROTO path determines
how far a message travels
-Path too restrictive: The message
won’t make it to the end point and
fails.
-Path too large: The message is
repeated through the network in a
large area and needlessly ties up
bandwidth.
-Use the path that meets your needs!
APRS Message Path
•Your UNPROTO path determines
how far a message travels
-Recommend starting with WIDE2-2 and
adjusting depending upon the final
destination.
-If the station is a single hop through a
digipeater, even WIDE1-1 would work!
APRS Bulletin / Message
•The good news is you don’t have to
manually create the message
packets. Most APRS software
handles the formatting.
APRS Message on APRSISCE32
APRS Message on APRSISCE32
•First you select message/send from
the menu.
•Then you enter the callsign
(including SSID if necessary) of the
recipient.
•Then the messagebox pops up.
•Enter text and check ACK.
•Click Send Button.
APRS Bulletin on APRSISCE32
APRS Bulletin on APRSISCE32
•First you select messages/
bulletins/create from the menu.
•Click on enabled checkbox.
•Select a number on the dropdown
(i.e. 1).
•Enter BRIEF comment.
APRS Bulletin on APRSISCE32
•Enter bulletin retransmit period
(i.e. 20 min)
•Select Via RF checkbox.
•Enter a valid RF Path (i.e. Wide2-2)
•Click on Accept Button.
•Disable once has been retransmitted
sufficiently!
ANSRVR on APRSISCE32
•Allows you to send message to a
“groupsö like
-APRSIS32(12) Notifications for APRSIS32
Own:KJ4ERJ-12
APRSISCE(2) Notifications for APRSISCE
Own:KJ4ERJ-12
BALLOON(9) HA Balloon alerts
Own:G6UIM
CDGAPRS(3) Cumbria Dumfries &
Galloway APRS Users Own:G4ILO
ANSRVR on APRSISCE32
•Allows you to send message to a
“groupsö like
-CDGVHF(2) VHF propagation alerts for
Cumbria, D & G. Own:G4ILO
CQ(2) CQ Calling Channel Own:KJ4ERJ-12
ECHOLINK(7) Echolink users. Send CQ,
give local node
FD(2) Field Day Contact Center
Own:KJ4ERJ-AP
ISS(6) ISS APRS Sched Own:G6UIM
ANSRVR on APRSISCE32
•Allows you to send message to a
“groupsö like
-JOTA(1) Jamboree On The Air
Own:KJ4ERJ-12
MARC(2) This is s test of trying to learn
Own:KA0AGC
ODARC(2) Orange Amareur Radio Club
Own:VK2ASY-2
OSR(1) OSR Own:SQ9MLI-1
ROCKETS(5) for rocket launches
Own:G6UIM
ANSRVR on APRSISCE32
•Allows you to send message to a
“groupsö like
-SARA(1) Sawnee Amateur Radio
Association Own:N4AC-7
SCOUTS(2) APRS for Scouting
Own:KC7QJO
UIMCAM(3) Webcam 91.84.215.75:81
Own:G6UIM
WOTA(6) Wainwrights On The Air group
for spots etc. Own:G4ILO
ANSRVR on APRSISCE32
•To send a message to the group, you
use the send message function in
APSISCE32 and
-Send to ANSRVR
-Text of message is CQ <Group>
<Announcement Text>, where , <Group>
is group name and <Announcement Text>
is the message, i.e. “CQ Echolink Check
Out Node XXX in Anytown, USA!ö.
ANSRVR on APRSISCE32
•The following commands can be sent
in a message
-? - Show all groups (# in parens is number
of members)
-? group - Show member count in group
-D show groups with descriptions, also
sending D <group> description text, will
supply a description of the group to the
server
ANSRVR on APRSISCE32
•The following commands can be sent
in a message
-L - List groups you are a member of (with
member count including self)
-J group - Join group quietly
-K group1 group2 group3 … - Quietly
Keepalive multiple groups (be careful of
APRS message length limits)
ANSRVR on APRSISCE32
•The following commands can be sent
in a message
-CQ group text - Join group and send text
to all current members, if the group does
not exist it will be created and you will
be the owner
-U group - Unjoin group
Echolink, IRLP, D-Star
•Check out the work on AVRS –-
Automatic Voice Relay System
-http://www.aprs.org/avrs.html
•Echolink has provisions to connect a
node to a TNC and send information
out on APRS.
•D-star has D-PRS capabilities.
-http://info.aprs.net/index.php?title=DPRS
Why APRS Messaging?
•Eliminates voice comm issues
-Spelling, phonetics, etc.
•Eliminates privacy legal issues
-Public hears just noise on scanners.
•Logged for review in the future.
-Good for debriefs.
•Can have multi-hop 80-200 mile range.
-Longer than simplex or single repeater.
Questions?
•Jeff Scoville
-ae5me@yahoo.com
•Scott Haley
-kd5njr@gmail.com
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