Transcript Fldigi & Digital Ham QSOs

Digital Ham Operations
An Overview - Mainly For Beginners
John MacFarlane VE7AXU / VA7PX
2013
Presented January 9, 2013
to the Surrey Amateur Radio Club, Surrey BC
with assistance from Brett Garrett VE7GM
Introduction
• Getting on the air on HF can be intimidating for a
new ham.
• I am assuming that you have a licence and have HF
privileges and you want to go beyond using VHF on
the repeater
• Digital modes are a great way to get introduced to
exciting on-air action with minimal investment.
• Its my hope that hams who are not currently
operating on HF will become active through these
exciting modes.
First Some Technical Background
• The basic element is the binary bit (0 or 1, on
or off, plus or minus, yes or no, on or off)
• Morse for example is on and off
• (Sound of a morse (CW) transmission) (Sound
recording courtesy of Brett Garrett (VE7GM)
using Fldigi sofware – more on that later)
What Are Digital Modes?
• Amateurs use an SSB Class-A transmitter to send and
receive (signals must be linear)
• They use a personal computer sound card to code
and decode the signals (numerical values at a fixed
rate) which create audio sounds. You can hear these
signals on the air – but the computer decodes them.
• Letters, numbers etc. can be encoded using these
techniques and transmitted over the air and decoded
at the other end
• Characters are coded so that each letter and
number etc. has a unique code, which often
takes at least five data bits and a
synchronizing bit per character.
• Each RTTY (radio teletype) character requires
7.5 bits – and at 45.45bps that sends 6
characters per second.
• RTTY is sent at 60 wpm
• PSK31 is sent at 35 wpm
• MFSK16 is sent at 40 wpm
Some modes use alphabets that have a variable
number of bits per second. Morse or PSK modes
frequently use characters with shorter sequences (eg.
in morse “e” is one dit) – in other digital modes
1
code for “space”
11
code for “e”
101 code for “t”
111
code for “o”
1011 code for “a”
1111 code for “n”
...... and so on ….
1010101101 code for upper case “Z”
By increasing the number of bits used it is
possible to send hundreds of different characters
(eg. useful for sending Japanese characters)
Signals are synchronized so that the receiver can
tell when one letter ends and the next begins so
a special serious of bits marks the end.
Noise on air can confuse the decoder losing the
data – causing errors at the receiving end – and
cause what looks like garble – noise gets decoded
too
• In digital signals there are built in methods to
allow errors to be automatically fixed, either
by ...
• the receiving station detecting the error and
asking the sender to send again, (Automatic
ReQuest repeat - ARQ)
• or sending extra information so that the
character can be reconstructed and corrected
without retransmitting (forward error
correction - FEC)
Digital Modes
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CW (morse code)
Pactor – used for sending email over the air.
RTTY (radio teletype)
PSK31 (phase shift keying at 31 baud)
Hellschreiber (sends a ‘picture’ of the character)
MFSK (sends lots of data to reduce errors)
Throb (very low speed – very accurate)
Olivia (requires precise tuning)
SSTV (slow scan television)
and others (each looks and sounds different)
What Equipment is Needed?
• Computer running Windows or Linux/Unix
• Transceiver capable of SSB and monitoring of ALC at
about 20 watts or less (can be an older second hand
rig)
• Interface between the computer and the transceiver
(can be home made or purchased)
• HF antenna (I use a wire and vertical very
successfully)
• Software to code and decode (good freeware is
available)
Some Digital Hardware
• Interface
– Usually a ‘box’ between the computer and transceiver connected by
cables
– Can use the internal sound card in computer
– Can be home-made
– Can be purchased from suppliers (not hugely expensive)
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SignaLink
Rig Expert
Rig Blaster
US Interface Navigator (by KK7UQ)
What Equipment is Needed?
• Computer running Windows or Linux/Unix
• Transceiver capable of SSB and monitoring of ALC at
about 20 watts or less (can be an older second hand
rig)
• Interface between the computer and the transceiver
(can be home made or purchased)
• HF antenna (I use a wire and vertical very
successfully)
• Software to code and decode (good freeware is
available)
My Setup
Some Popular Digital Software
Software
Comment
Source
MixW
Many different digital modes. Logs QSOs and
handles eQSL and LOTW. Costs about $50 –
and if you buy it download it through their US
internet site! Developers seem to have lost
interest in supporting it.
www.mixw.net
Digipan
Soundcard freeware. PSK31 & PSK63. Monitors
multiple channels, logs QSOs. Can view
multiple QSOs simultaneously – a great starter
program
www.digipan.net
Fldigi
Soundcard freeware. Many many digital modes
– many hams consider this the best digital
program on the air.
www.w1hkj.com
Hamradio
Deluxe (PSK31
DeLuxe)
Soundcard freeware. PSK31. Part of a suite links to logging program. Many many modes –
the most popular program on the air but a very
steep learning curve because it has so many
great features.
hrd.ham-radio.ch
What Is PSK?
• This digital mode introduced by Peter Martinez
G3PLX and uses phase modulation and special
character coding
• Allows robust narrow bandwidth keyboard “chat”
between two stations
• Bandwidth is equal to the baud rate (BPSK31 is
31Hz)
• Originally designed for a Windows soundcard using
an SSB transceiver with PSK signal generated and
received as an audio tone
• (PSK sound recording)
PSK mode
• Similar in visual appearance to text messaging on a
computer using narrow bandwidth
• Doesn’t require good hearing by users
• Operates extremely well under low power – 30 watts
is generally the maximum for average use and will
get you around the world. I use 20 watts.
• Users tend to be very friendly and very helpful
• Equipment is very modest and software can be free
or at low cost
• This is the mode to start in as a beginner
FLDigi Software
• Its FREE (download it off the web from the
official site)
• Mildly difficult to configure (ask for help if
needed – there is a great online help group)
• Has on ‘on board’ log in the program
• Can be “bridged” to N1MM or to DXKeeper for
logging with more robust features
Bridge to Logging Software
• Google “bridging software”
• www.n2amg.com/software/fldigi-dxlabsgateway/
• Can go from Fldigi to many different logging
programs
• Can ‘bridge’ from and to many other programs
too with freeware provided on this site
Assigning Com Ports
• All digital software involves some configuring
• You can see the port assignments on your
“system” in the control panel
• You’ll need to know those allocations so you
can set up your software on your computer
• They are all different so you need to see how
your computer is handling your allocations
• Find out more on how to check this on the
internet – or ask an ‘elmer’
Interface set-up screen for a hardware
computer interface
Some Other Digital ‘Flavours’
MFSK16, DominoEx
RTTY
QPSK and other
flavours
WSJT65
Olivia: 2K, 1K, 500,
250,125 baud
Packet
Contestia: 2K, 1K, 500,
250,125 baud
Amtor/Pactor
RTTYM
SSTV: many styles
Throb
Hellschreiber: Feld Hell, FM
Hell 245, FM Hell 105, PSK Hell
MT63: 2K, 1K, 500
CW
Clover (related to PSK)
Stream
Some Suggested Operating Frequencies
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160m – 1838 Mhz
80m – 3580 Mhz
40m - 7035 – 7045 and 7070 Mhz
30m – 10142 Mhz
20m - 14035 & 14070 Mhz
15m – 21070 Mhz
(Also on 10m, 12m, 17m)
Example of a “good” signal
Example of a “bad” signal
Operating Screen Examples
Empty carrier
Noise and weak signal
Over-driven signal
(too wide)
RTTY signal
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Popular contest mode
Fast action
Lots of users
Good for DX
Easy to use and set up
(Example of sound recording)
Example Hellschreiber signal
(Example of sound recording)
MFSK Signal
Good for accuracy under difficult conditions
Good for message handling
Signal seen vertically
Ignores lightning
Tuning is critical
(Example of sound recording)
Signal seen horizontally
Logging Software
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Keep a log – its good operating practice
You need it to send and receive QSL cards
You need it if you ever apply for awards
Legally, a log of your transmissions would be invaluable in
proving your innocence in an interference complaint. A record
of dates, times, frequencies and so on, will be evidence of your
operating activity that can be compared to the dates and times
of interference.
• Contact records can be an aid in determining which bands and
times of day seem most useful for your station.
• There is the pleasure of looking back through the log at the
contacts
DX Keeper
• Software is free (part of a suite similar to
N1MM) and can be bridged to most popular
digital software programs
• Active ‘reflectors’ for getting information and
help
• Easy to use and set up
• Regular updates provide (can be subscribed)
DX Keeper
Reflector Groups
• Join the reflector groups for the software packages
you use – and pay attention to the postings
• Don’t be shy about asking for help – no such thing as
a dumb question
• But search the history in each one to see if someone
already asked it and got an answer – they all get
saved in the archive
• Yahoo groups hosts some of the best
• Also look on Eham.com – particularly in the “Elmer”
forum
QRZ.com
• Look up your callsign on QRZ.com – its listed there
automatically
• Sign up so you can edit your entry
• Check your address and add your email address so
other hams can contact you
• Give a brief bio on your ham activities and interests
• Indicate whether you exchange QSL cards – and if you
do what methods do you use
• Update the entry even if you don’t do much operating –
even your acquaintances may look you up
LOTW & eQSL
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Seriously consider exchanging QSLs
Traditions method is a printed card to confirm contacts
eQSL is an electronic method
LOTW is the most serious approach (run by the ARRL)
You have to “join” both LOTW is free and eQSL encourages
donations
• DX Keeper handles both straight out of the logbook
allowing both upload and download of confirmations