Sound card digital modes

Sound card digital modes
Sound card data modes
and NBEMS
Presented to Hendricks Co. ARES®
February 28, 2015
Bob Burns W9BU
Chris Harrison KD9BIX
Wayne Michael AC9HP
Agenda
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Overview of available digital modes
Applications to auxiliary communications
Hardware
Software
Demo
Audio samples
• Audio samples for the modes mentioned in the
following slides can be found here:
▫ Modes supported by fldigi:
http://www.w1hkj.com/FldigiHelp3.21/Modes/index.htm
▫ Additional audio samples:
http://wb8nut.com/digital/
Original digital mode
• CW
▫ On-Off keying of the carrier
▫ Very narrow bandwidth
▫ No error correction
Original digital modes
• RTTY
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Frequency Shift Keying, typically 170 Hz shift
100% duty cycle
As fast as 20 wpm CW
Still popular for contesting
No error correction
Requires:
 FSK radio and keying circuit or…
 AFSK using sound card
Hardware decoder modes
• AX.25 Packet
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Error detection, retransmit until it’s correct (ARQ)
Store and Forward, digipeaters
1200 baud common, 19,200 baud max
Dedicated TNC or sound card packet engine
Used on HF (300 baud), VHF (1200 baud), or
UHF (9600+ baud)
▫ APRS uses Packet
Hardware decoder modes
• AMTOR (aka SITOR)
▫ Specialized form of RTTY
 FSK at 100 baud
▫ Error detection and correction, ARQ
▫ Hardware or software
▫ No longer popular
Hardware decoder modes
• PACTOR I/II/III
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Combination of Packet and AMTOR
Error correction, ARQ
Can send large files in difficult conditions
Hardware only, PACTOR I can be RX w/ software
PACTOR II and III are proprietary
• Clover
▫ PSK, full duplex
▫ Proprietary
Sound card modes
• BPSK 31, 63, 125
QPSK 31, 63, 125
▫ Popular for keyboard-to-keyboard QSOs
▫ No error correction
• JT65
JT9
▫ Very weak signal
▫ Very slow data rate
Sound card modes
• Olivia MFSK
▫ Olivia X / Y, X=number of tones, Y=bandwidth
▫ Usable with very weak signals
▫ Forward Error Correction
Sound card modes
• MT63
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Fast, noise resistant
PSK
500 Hz, 1000 Hz, or 2000 Hz
Forward Error Correction
MT63-2KL takes about 1 minute per kb
WinLink
• World-wide message (e-mail) system that uses
radio and the Internet
• Hub and spoke system of Radio Message Servers
(RMS) and Common Message Servers (CMS)
▫ Users connect to an RMS
▫ RMS’s connect to a CMS
• AX.25 Packet on VHF/UHF
• Pactor I/II/III or WinMor on HF
▫ WinMor—non-proprietary sound card mode
Auxiliary Communications Applications
• Served agencies have an increasing need for
accurate data communications
▫ Roster of evacuees
▫ Lists of medications
▫ Complicated directions to a site
• Error correcting modes a plus
• Must be easy to configure in the field
• We need to provide more than just voice comms
from a ham with a handheld radio.
Narrow Band Emergency Message
System (NBEMS)
• Uses several programs developed by W1HJK
▫ fldigi – general purpose data engine
▫ flmsg – messages handling, ARRL Radiograms,
ICS forms
▫ flarq/flwrap – file transfer, file compression
▫ flamp – multi-cast file transfer
• Public License, i.e. free
• Windows, Linux, Mac versions
NBEMS philosophy
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Keep it cheap
Keep it simple
Use open source software
Don’t depend on infrastructure (repeaters,
digipeaters, Internet)
• Make it fun
• Any computer, any radio.
What hardware?
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Radio
Antenna
Power supply
Computer (Windows, Linux, Mac)
Sound card interface
▫ On VHF/UHF, can use audio coupling
Sound Card Interface Requirements
• Rx audio from radio to computer sound card
• Tx audio from computer sound card to radio
▫ Both Rx and Tx need good audio isolation
▫ Easy level adjustments a plus
• PTT
▫ VOX will work
▫ Hardware keying better
• Built-in USB sound card
▫ Use computer’s sound card at your own risk
Sound Card Interface Options
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Homebrew
BuxComm Rascal GLX ($80)
Tigertronics SignaLink USB ($120)
West Mountain Radio RIGblaster Advantage
($200)
• ZLP Electronics various models ($50-240)
• Microham Digikeyer II ($329)
• Timewave Navigator ($375)
Radios with built-in sound cards
• Icom
▫ IC-7100
▫ IC-7200
▫ IC-7600
• Kenwood
▫ TS-590
• Yaesu
▫ FT-991
How to configure hardware?
• Build or buy a cable to connect sound card
interface to radio
• Configure sound card interface
▫ Set jumpers
• Install drivers
• Connect USB cable
• Check Windows Device Manager for COM port
assignment.
How to configure radio?
• USB for most digital modes
• Receive
▫ Turn off noise reduction, notch filter, noise blanker
▫ Fast AGC
▫ Use IF bandwidth adjustment with caution
• Transmit
▫ Turn off compression
▫ Turn off equalization
▫ Adjust sound card level and mic gain for minimum
ALC action
▫ Medium power
Acoustic interface
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No sound card interface needed
Use any radio
Hold radio speaker to computer mic
Hold radio mic to computer speaker
Manual PTT
Works well on VHF/UHF FM
▫ Even through repeaters
• Use MT63-2KL mode.
fldigi
• fldigi=Fast, Light, Digital
• Uses sound card to decode received signals and
encode transmitted signals
• Keys radio (if supported by interface)
• Old, slow computers work fine
• Designed for keyboad-to-keyboard comms
• Macros eliminate repetitive typing
flmsg
• Built-in templates for common message formats:
▫ ARRL Radiograms
▫ ICS forms
▫ Custom templates
• Uses check-sums ensure accuracy
▫ Sending station computes check-sum for sent message
and inserts check-sum into message
▫ Receiving station computes check-sum for received
message and compares to sent check-sum
▫ If check-sums match, error-free message
▫ If check-sums don’t match, resend message
• flmsg can automatically open received messages.
How to configure software?
• Download and install fldigi
▫ Configure settings
• Download and install flmsg
▫ Configure settings
fldigi set-up wizard—Operator info
fldigi set-up wizard—Audio devices
fldigi set-up wizard—Transceiver
(only if your sound card interface has transceiver
control)
fldigi set-up wizard—Tabular data
(not necessary for NBEMS)
fldigi addl set-up—Modems—MT63
fldigi addl set-up—RSID
fldigi addl set-up—RSID enable
• Enable RxID on main window
• Enable TxID on main window
flmsg set-up—Personal
flmsg set-up—Date/Time
Configure fldigi for NBEMS
Advanced topics
• Using flarq/flwrap for file transfer
▫ Binary files
• Using flamp for multi-casting
• Sound card calibration
• Packet for local VHF/UHF
▫ OutpostPMM
• Promote local activity.
Practice, practice, practice
• Check into nets
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IN DTN, 3.5840 +1 kHz, Mon-Fri 9:00am, Olivia 8/500 *
IN ARES DN, 3.5840 +1 kHz, Wed 8:30pm, Olivia 8/500
MI DTN, 3.5830 MHz +1 kHz, Tue/Thu/Sat 7:00pm, Olivia 8/500 *
KY DN, 3.5850 MHz +1 kHz, Wed 8:30pm, Olivia 8/500 *
OHDEN, 3.585 MHz +1 kHz, Tue 8:00pm, Olivia 8/500 *
PA NBEMS Net, 3.5835 MHz +1 kHz, Sun 10:00am, Olivia 8/500
PA NBEMS Net, 7.0730 MHz +1 kHz, Sun 11:00am, Olivia 8/500
US East NBEMS Net, 7.0360 MHz +1.5 kHz, Wed 7:00pm, Olivia 8/500
* May use other modes
On-line resources
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tigertronics.com
w1hkj.com
arrl.org/nbems
FSD-218
▫ arrl.org/files/file/Public%2520Service/fsd218.pdf
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wpaares.org
youtube.com/user/davekle38sp
youtube.com/user/StanislausCountyARES
oliviamode.com
wb8nut.com/digital
Demo
• Using two stations on 80m with dummy loads
and sound card interfaces
▫ Establish communications
▫ One station sends message
▫ Other station sends reply
• Using two stations on 2m with antennas, one
station using acoustic coupling
▫ One station sends message
▫ Other station sends reply
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