Digital Communications - Cascade Amateur Radio Society

LDS ECS Training
17 March 2012
Digital Communications
Gary J Takis – K7GJT/NNN0GJT
Mtn View Ward, Vancouver Stake
Clark County ARES/RACES EC/RO
N-MC MARS
NCS SHARES
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Lot’s of information to cover!
Kind of like… “trying to drink from a firehose”
That’s ok… it will be on the C.A.R.S. website!
Digital Communications
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How is it different than voice?
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Subjects to cover
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Amateur Radio Digital Mode History
Amateur Radio Digital Modes
Transmission Coding Schemes
Two Basic Digital Technologies (TNC & Soundcard)
‘TNC’ Technology, Modes & Software
‘Soundcard’ Technology, Modes & Software
PACKET
APRS
Winlink 2000 system
High Speed Multi-Media Mesh (HSMM-Mesh)
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Amateur Radio Digital Mode History
• The ‘Original Digital’ mode
– Presence or absence of carrier (1, 0, 1, 0, 1, etc.)
– CW!
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Amateur HF Radio Digital Mode History
• Started as Mechanical Hardware Specific
– 1849 Landline based teleprinter operations began
– 1920 Rudolf Hell invented Hellschreiber
– 1930’s RTTY (Radio TeleTYpe) [Military RATT/SCRT]
• 1980’s started computerizing the RTTY signals
• Prior to 1995 the only ‘legal’ HF digital mode
that was authorized by the FCC were those that
used the standard Baudot codes; e.g. RTTY
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Amateur HF Radio Digital Mode History
• In 1995, the FCC opened to door to other
modes (ASCII based) and declared that any
new mode coding were legal as long as they
were published in the public domain.
• … and the “Barn Door” opened!
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Amateur VHF/UHF Digital Mode
History
• Been around since the mid-1960's
• First seen on the amateur bands in 1978
through research done in Montreal, Canada in
1978
• VADCG TNC board in 1980 (TNC-1)
• TAPR TNC board in '84-'85 (TNC-2)
• The PACKET radio revolution ignited when TAPR
sold over a thousand TNC-2 kits
• 1969 – ARPANET & 1970 ALOHANET
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Digital Messaging Systems
• Station-to-Station (Peer to Peer)
• Routed point-to-point (Hierarchical Addressing)
• Bulletin Board (BBS)
• Global (Winlink eMail)
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Digits to Tones - then - Tones to Digits
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Amateur Radio Digital Modes
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Transmission Coding Schemes
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CW – Continuous Wave (on-off)
AFSK – Audio Frequency Shift Keying
BPSK – Binary Phase Shift Keying
FSK – Frequency shift Keying
MPSK - Multiple Phase Shift Keying
PSK - Phase Shift Keying
QPSK - Quadrature Phase Shift Keying
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Two Basic Digital Methods
• Terminal Node Controller (TNC)
– Hardware based
– External ‘smart box’ converter for ‘digits-to-tones’
and ‘tones to-digits’
– Not inexpensive
• Soundcard
– Software based
– External or Internal PC microprocessor converter for
‘digits-to-tones’ and ‘tones to-digits’
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External TNC Technology
• TNC (Terminal Node Controller )
– Typically external to PC
– Many mfg’s (SCS, Kantronics, Timewave/AEA, etc.)
– Some have Digital Signal Processing (DSP) built-in
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External TNC Devices
SCS, AEA/Timewave, Kantronics, etc.
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External TNC Modes
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PACTOR I, II, III & IV
AMTOR
RTTY
PSK31
CW
PACKET (HF & U/VHF
NAVTEX
TDM
Robust PACKET
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External TNC Software
Generic
• Alpha
• Airmail
– PACKET/PACTOR
• Paclink
– PACKET/PACTOR
• PAXON
• RMS Express
– PACKET/PACTOR
SCS Specific
• NCWinPTC
• NCWinPTC Term
• EzTransfer
• SCS Mail
AEA/Timewave Specific
• PCPakRatt (CSS)
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Soundcard Technology
• Soundcards
– Internal to PC (built-in)
– External to PC (Tigertronics SL-USB, West
Mountain Radio, US Robotics Navigator, MixW
RigExpert, etc.)
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External Soundcard Devices
Tigertronics, US Interface, West Mountain Radio, Buxcomm
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Soundcard Modes
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BPSK 31/63/125
QPSK 10/31/50
MPSK
PACKET
CCW
PACTOR 1
AMTOR FEC
RTTY
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MFSK 8/16
OLIVIA
THROB
Domino
PAX
ALE
COQUELET
Hellschreiber
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SSTV
MT-63
CHIP
APRS
Contestia
HF FAX
WINMOR
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Soundcard Software
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Airmail
DIGIPAN
DigTRX
DM-780 (HRD)
Feld Hell
FLDIGI
FTV
Hamscope
JVComm32
MixW
MMSSTV/RTTY
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MT63
MultiPSK
NBEMS
NBF
PacLink
Paxon
PcPakRatt
RDFT
RMS Express
Sally
SCAMP
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SlowFeld
Stream
Throb
TrueTTY
WinDRM
WinPack
WinPSKse
WinWarbler
WSJT
XPWin
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HRD - DM 780
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MixW
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MultiPSK
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FLDIGI
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DIGIPAN
CCARES/RACES
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Paxon
CCARES/RACES
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WinWarbler
CCARES/RACES
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Accuracy
• Broadcast Mode
– Character loss is not important
• Error Checking modes
– FEC (Forward Error Correction)
– ARQ (Automatic Repeat-reQuest)
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Accuracy
• The FEC mode is used where absolute
accuracy is not paramount but a higher degree
of message exchange reliability is.
– A redundant data transmission technique that
transmits the information using a predetermined
algorithm (no handshaking)
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Accuracy
• The ARQ mode is used where absolute accuracy
is paramount on the exchanged message.
– It uses a handshaking technique to ensure absolute
accuracy in the exchange of data.
– When a block of the message is not received with
100% accuracy, the receiving station requests the
entire block to be resent.
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“Waterfall” Displays
AMTOR
CW
FAX
HELLSCREIBER
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“Waterfall” Displays (cont)
FSK31
MT-63 (1000HZ)
PACTOR 1
PACTOR 2
PACTOR 3
PSK 31/63/125
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“Waterfall” Displays (cont)
SSTV
THROB
VHF PACKET
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Making the connection “without wires”
Receive = Radio Speaker - into - Computer Microphone
Transmit = Radio Microphone – into – Computer Speaker
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Making the connection with wires
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Soundcard Interface - Improved
• Two issues
1. TX & RX Audio
isolation
2. PTT control
Note: Buxcomm Product Shown
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Digital Messaging Schemes
1. Keyboard-to-Keyboard (Peer-to-Peer)
- Typed message on keyboard
2. Station-to-Station (Peer-to-Peer)
– Typed or text file message to screen
– Typed or text file message to personal mailboxes (MBX)
3. Local Message Boards (BBS)
– Central mailbox location for messages
4. Wide Area Systems
– Winlink 2000 Global Radio eMail System
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PACKET
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PACKET System Options
Digipeater
BBS
Station “D”
Station “B”
Station “A”
Station “C”
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MS HyperTerminal & WinPack
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OutpostPM
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Create by Bob Bruninga, WB4APR
• Amateur PACKET Reporting System
– “Maps and Messaging”
– Over 40,000 users
– Most common use is position reporting
– Weather
– Telemetry
– 144.39 MHz
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Winlink 2000
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Is Winlink a system or software?
• Winlink is the system
– We operate in the Winlink system
• Airmail, RMS Express is the
software to access the system
– We install the software to do so.
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Winlink 2000 System
5 Fully redundant, mirrored,
and worldwide dispersed
Common Message Servers
(CMS)
RMS ‘Gateways’
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Radio Message Servers “RMS” gateways are always connected to the
CMS System via the Internet in a star network topology, serving as radio
interface nodes on the Winlink 2000 network.
– RMS Pactor for HF provides short or long haul availability to Internet e-mail.
– RMS Packet for VHF/UHF “last mile” e-mail availability to Internet e-mail.
– RMS Relay provides continual communications with the CMS system when no
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Internet is available to bridge the “last mile.”
Winlink Amateur Radio System
• 5 Common Message Servers (CMS)
– San Diego
– Perth, Australia
– Wien (Vienna), Austria
– Halifax, Nova Scotia Canada
– Brentwood, TN
• 133 HF RMS Stations (FCC Ham channels)
– PACTOR, WINMOR, Tri-Mode, BPQ32
• 473 UHF or VHF RMS stations
– AX.25 PACKET protocol
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Winlink Gov’t/MARS System
• 5 Common Message Servers (CMS) (<< Same servers for Ham side)
– San Diego, CA
– Perth, Australia
– Wien (Vienna), Austria
– Halifax, Nova Scotia Canada
– Brentwood, TN
• 65 HF RMS Stations (75 NTIA Channels)
– PACTOR (46), WINMOR (19) , Tri-Mode, BPQ32
• 23 VHF RMS stations
– AX.25 PACKET protocol
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Winlink 2000 Access Modes
• TELNET (directly into your ISP/Internet connection)
• PACKET VHF or UHF RMS
• WINMOR HF RMS
• PACTOR I, II, III, IV HF RMS
• Tri-Mode RMS
• BPQ-32 RMS
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Winlink 2000 Topology
Radio
Message (aka “Gateway”)
Server
(HF/VHF/UHF)
TELNET
The Internet “Cloud”
USER
TELNET
TELNET
AIRMAIL
RMS Express
PACLINK
Common
Message
Server (4)
Connected to Client PC or Network!
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Winlink Users
• Approximately 14, 000 ham client accounts
• Approximately 2,000 MARS client accounts
• Approximately 10,000 Weekly Radio users communicating with
over 98,000 Email recipients,
• An average of 150,000 messages or 280,000 minutes monthly
• An average duration of 3.4 Minutes at 3,600 bytes/per message.
• The average time from message origination to pickup for
delivery is approximately 1.0 minute, regardless of distance.
• The greatest growth is now in Emergency Communications
preparedness.
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Winlink Station
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RMS Station
(HF MARS Winmor & VHF MARS & UHF HAM PACKET)
CCARES/RACES
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Airmail
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RMS Express & Paclink
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Digital Addressing (Hierarchical)
• PACKET (BBS)
k7gjt
• PACKET (Hierarchical)
[email protected]
• Winlink (standard internet SMTP)
[email protected]
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HSMM-Mesh
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The Topology
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How does it work?
• An HSMM-MESH node provides an endpoint
connection AND a repeater
• If one endpoint cannot see its desired destination,
but CAN see nodes in between, the data will hop
from one to the next until the final connection is
made…. completely automatically
• If one repeating node falls out, the software
automatically re-routes traffic through other
available nodes
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The Hardware
• Router: LinkSys WRT-54G Series
– 12VDC @ <1A
– Uses “RP-TNC” antenna connector
• Antenna Options Below
– Typically Use ‘RP-SMA’ and ‘N’ connectors
• Bi-directional amplifiers available
Verticals
8 Dbi
12 Dbi
15 Dbi
Circular, Rectangular or Flat Panel = 8-24Dbi
12 El beam = 20Dbi
16 El beam = 24DBi
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What can we do with it?
• Connect two or more devices…
- Computers (s)
- Webcam(s)
- VoIP phone(s)
- Server(s)
- Anything that ‘talks’ TCP/IP over a computer network
• NOTE: An internet connection to one node
provides the entire HSMM-Mesh network with
internet access (FCC Part 15/Part 97 issue)
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A Typical
Portable Omnidirectional
Node
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A Typical
Portable Unidirectional
Node
@ South
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Austin Medical Center
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Questions?
[email protected]
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Yep, that’s me!