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Join The Fun! Digital HF: what are you waiting for? A presentation for the Gloucester County ARC, NJ by Jim Wright (N2GXJ) and Ken Newman (N2CQ) – PowerPoint PPT presentation

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Title: Digital%20HF:%20what%20are%20you%20waiting%20for?

Join The Fun!
  • Digital HF what are you waiting for?
  • A presentation for the Gloucester County ARC,
    NJ by Jim Wright (N2GXJ) and Ken Newman (N2CQ)

Why add digital modes?
  • Be honest
  • Tired of your old radio?
  • Too much static in the headset?
  • Frustrated with band conditions?
  • Tired of the same old operators?
  • Want to meet some new hams?
  • Want to enjoy more DX?

Then maybe the HF digital modes are for you!
HF digital modes
  • To quote long time ham, NB6Z The distinguishing
    features of live HF digital operation today are
    the use of lower power, compact or indoor
    antennas, and courteous operating technique. This
    reverses the trend of several years ago
  • Unexpected operating benefits
  • When operating radio in digital mode, theres no
    microphone, no noisy speakers, no headset
  • Break free of the shack! With a laptop, can enjoy
    quiet time with your significant other, sitting
    together on the couch (pretending) to watch your
    (their) favorite (reality) TV show, while still
    chasing DX! ( Just saying Not that anyone
    would do this... Would they?)

Band conditions
  • Conditions are terrible. The bands must be
  • Not so fast!
  • It used to be that you had to hear em to work
  • Not so with some of the modern digital modes! To
    put it in perspective, a 2002 study found
    majority of CW ops could copy at an S/N ratio of
    0db, but less than 4 could copy down to -7db.
    Contrast that with digital mode Olivia which
    can be decoded when it is 10-14 db below the
    noise floor (noise is 3x stronger than the
    signal!) And digital mode JT65HF, with QSOs
    possible to -20db! ref The Weak-Signal
    Capability of the Human Ear, Ray Soifer, W2RS,
    Proceedings of the Central States VHF Society
    Conference, 2002
  • Low sunspots, spectrum crowding, fading, impulse
    noise, static crashes, QRM, QRN, QSB, you name
  • Modern digital modes are popular because they can
    work well, even under less than ideal conditions!

Bands seem dead? Try HF digital modes instead!
Enjoy more DX!
  • Its hopeless. Ill never get DXCC.
  • Wrong! Were lucky living on east coast USA!
  • You just need to try HF digital modes, theyre DX
    friendly! (See the 4 hour reception map on the
    title page of this presentation)
  • Its not uncommon to log more than a dozen
    countries in a single hour with one mode (PSK31)
    on one frequency (14.070 Mhz).
  • Worked All States (WAS) and mixed mode DX Century
    Club (DXCC) awards in less than a year with under
    50W and only a dipole antenna up in the attic?
    Yes, you can! (e.g. n2gxj)
  • If youre an SSB and/or CW op, for fun, why not
    consider adding digital modes to your existing DX

Digital modes are DX friendly!
Meet new hams!
  • Theres a growing community of new digital users
    out there all over the globe, on all bands, at
    all hours of the day!
  • Digital is the fastest growing area of our
    growing ham radio hobby! ref2

ref1 http//
4/21/2012 ref2 Ham Radio for Dummies,
W.Silver, WileySons pub
Enjoy more DX!
  • East coast stations regularly catch digital DX

ref http//
Enjoy more DX!
ref http//
  • Maybe add digital modes to your existing DX

A typical Saturday afternoon
  • How many digital QSO can you count in this 3khz
    of audio bandwidth?

Panoramic simultaneous decode!
  • That looks fun! Ready to give it a try?

Adding digital capabilities
  • Goals
  • Upgrade, not replace, existing HF radio ()
  • Preserve your existing CW/SSB capabilities!
  • Add a whole new world of HF digital
  • How to? The options
  • If your radio is an SDR, just add digital
    software ?
  • Else, connect audio jacks/ptt on your radio via
    an adapter to ports on your PC, then add digital
    software to your PC
  • Via build-it-yourself interface, or
  • Via buy-it-yourself interface

Build or Buy interface
  • Basic elements of either approach
  • (RX) Audio from radio into the PC
  • (TX) Audio from PC to the radio
  • (TX KEY) PTT, or VOX, for transmit

ref http//
  • For the saver, DIY enthusiast
  • For SWL, no circuit needed. Just let computers
    built-in mic listen to the radio
  • For clean RX/TX, use cables and the PCs sound
    card for A/D, D/A conversion
  • Simple connection shown above, with VOX enabled
    on radio for TX, may be all you need
  • If ground loop issues, use audio transformers, as
    shown on right

ref http//
If you are thinking of BIY, a recommended
reference http//
Buy it Yourself
Ref Pictured units and trademarks are property
of their owners SignaLink
(Tigertronics), RIGBlaster (West Mountain Radio),
  • Easy install
  • Vendor often can supply cables specific for your
    radio model
  • Interface simplicity
  • USB between Box and your PC (most PCs dont have
    RS232 anymore)
  • Interface box contains its own soundcard
  • Soundcard in PC can still be used for PC sound

Digital mode software
  • Hundreds of choices
  • Some that may have been good in 1999, or even
    2007, just cant compare to the most popular
    choices in use today
  • Some features to consider
  • Continued support/upgrades
  • Compatibile with your PCs OS
  • If it has the modes you want
  • Ease of integration with contesting/logging
  • Interfaces with online service(s)
  • Callsign lookup
  • Electronic QSL services
  • Spotting networks
  • Reverse beacon networks
  • Cost

Multimode or specialty?
  • Start with a multimode software package
  • Lets you operate many popular modes without
    switching programs
  • Learn once, use for many modes, higher enjoyment
  • Tend to be more modern, more features, more fun
  • Get familiar with one, then can compare with
    others, at your leisure
  • Later can look into specialty programs, e.g.
  • Weak signal beacons/reception reporting (e.g.
  • Weak signal QSOs (e.g. JT65HF),
  • Digital slow scan TV (e.g. EasyPal),
  • Digital modes on smartphones (see cover story of
    May 2012 QST magazine)

Top Picks (imo)(alphabetical)
  • Fldigi (http//
  • Available for Linux, OSX, and Windows. Popular
    for narrowband messaging, emergency comms use.
  • HRD/DM780 (http//
  • Package includes integrated rig control,
    decoders, logger, and much more. Windows. Pay
    after June 2012.
  • MixW (http//
  • Windows. Favored by many digital contesters. Pay.
  • Multipsk (http//
  • Some consider this the swiss army knife of
    digital software packages. Register (pay) version
    more full featured.
  • older (Digipan, Hamscope) try a few, see what
    works for you!

Ref with links to these, and more
Topics for future presentations
  • Many digital software packages integrate with
    electronic logging systems (like LoTW, eQSL,, and online services (such as
    callsign lookup (e.g., DX clusters, and
    reverse beacon networks (above qsos logged in
    last hour,
  • Each of these are involved enough to be candidate
    topics for future discussion!

  • These are the ones to start with
  • Radio Teletype (RTTY) Frequency Shift Keying
  • PSK31 Phase Shift Keying
  • After those, you might consider adding some of
    these modes to your digital DX repertoire
  • MFSK - if one or two tones are good, why not
  • JT65a - just for DX qso credit. No conversations
    at all.
  • Olivia - conversational, even for very faint
  • Hellschreiber let your eyes do the fax
  • SSTV - sending regular and high def pictures over
  • How to recognize these modes, and where to look
    for them on the dial? (well cover that next!)

When getting started
  • Tip 1 Digital modes are typically 100 duty
    cycle, often with long duration transmissions.
    Care should be taken to avoid overheating and
    damaging your radio finals.
  • Keep power levels low
  • consider temperature monitoring, additional
    cooling, fans
  • Tip 2 Overdriven audio is most common cause of
    band splatter. Is easy to avoid being the guy
    with the ghosting shown above.
  • Turn off SSB compressor
  • Reduce audio drive levels to below AGC threshold

  • One of the oldest modes, in use since WW II
  • Popular for DX and world-wide radio contests
  • Continuous transmission using FSK (or AFSK)
    between two tones
  • Common 28.080-28.100, 21.080-21.100,
    14.080-14.099, 7.080-7.100 Mhz
  • Typical setting 45.45 baud, 170Hz shift between
  • Support for other bauds/shifts common, as is
    reverse to allow use with USB or LSB radio
    setting (EU stations tend to use USB)
  • Limited character set (e.g. UPPER CASE ONLY)

  • RTTY QSOs tend to be brief, particularly for busy
    DX stations, and for contests where only calls
    and signal reports need to be exchanged (no
    names, serial numbers, nor locations
  • Simulated brief QSO example
  • gt CQ CQ CQ DE N2GXJ N2GXJ (n2gxj calling cq)
  • lt W2MMD W2MMD (w2mmd answers)
  • gt W2MMD 599 599 W2MMD (n2gxj acknowledges w2mmd,
    with sig report)
  • lt N2GXJ 599 TU (w2mmd confirms report, and
    returns n2gxjs)
  • gt 73 DE N2GXJ QRZ? (n2gxj confirms report, and
    asks for next station)
  • Of course, RTTY is a keyboard typing mode, so you
    can ragchew for hours instead if you want
  • and some do!

Operating RTTY Split
  • Rare DX and DXpeditions will often run RTTY
    split, where they TX on one frequency, and
    listen in range up/down 1-5 Khz
  • e.g. CQ CQ 7O6T UP 1-2
  • Tip use split capability of your decoding
    software, instead of your radios split
    capability when up is lt3 Khz
  • See DX stations TX and how he is up answering
    on same waterfall
  • Easy drag/drop your TX freq to most likely place
    to be answered next!

PSK (31,63,125)
  • Very popular!
  • 31Hz bandwidth advantages QRP DX, less spectrum
  • Seems like you can always find some PSK tracks
    on air!
  • Wheres the band open to? (Just check whos on
    the psk frequencies!)
  • Common dial frequencies 50.290, 28.120, 24.920,
    21.070, 18.100, 14.070, 10.140, 7.040, 3.580,
    1.838 Mhz.
  • PSK in different widths (31, 63, 125 Hz) PSK31 is
    better decode, but PSK63/125 faster for contests
  • varicode, so lower case letters send faster (cq
    cq cq)

  • PSK QSOs tend to be push-button English language
    macros, with certain fields filled in by the
    software. Simulated example
  • gt W2MMD DE N2GXJ Hello OM, UR RST 599 599 QTH
    Sewell, New Jersey LOC FM29kr Name Jim
    Jim Clubs GCARC, EPC 15956, PODXS070 1424 How
    Copy? BTU W2MMD de N2GXJ kn
  • (and on-and-on, often with brag file
    about antenna, etc)
  • Even with prevalent macro use, once basics are
    out of the way, its still possible to end up in
    30 minute typing ragchews, especially on lower

Other modes MFSK16
  • MFSK16 frequency shifts between 16 tones to
    improve signal detection in presence of random
    distortions, including multipath
  • Look for signals near 14.078, 3.584 Mhz (ref
  • Not seen that often. Other digital modes based on
    frequency shifting between multiple tones are
    more common (including JT65a for HF, discussed

Other modes JT65a
  • Developed for moon-bounce, then adapted for HF,
    is a popular weak signal mode for DX (many
    signals shown in the 1.5 Khz audio trace above)
  • 25 Watts is considered high power! Decodes to
    -20db S/N levels possible
  • Common dial frequencies 28.076, 21.076, 18.102,
    14.076, 7.076 Mhz
  • QSOs are SLOW. Stations alternate even/odd
    minutes with 46.8 second transmissions
  • Coordinated time synchronization of PCs needed
    for reliable decodes

  • JT65A QSOs are very rigid and just convey the
    bare essentials callsigns, signal reports, and
    locations. (no chat mode)
  • Simulated example
  • odd gt CQ N2GXJ FM29 (n2gxj calling cq from
    Maidenhead grid square location FM29)
  • evenlt N2GXJ JE1LET PM95 (je1let answers, giving
    his location)
  • oddgt JE1LET N2GXJ -13 (n2gxj acknowledges
    je1let, returning signal report of -13Dbm)
  • evenlt N2GXJ JE1LET R-12 (je1let confirms report,
    and returns n2gxjs report of -12Dbm)
  • oddgt JE1LET N2GXJ RRR (n2gxj confirms receipt of
    his signal report, so je1let wont resend)
  • evenlt N2GXJ JE1LET 73 (je1let says thanks, n2gxj
    can then do same, or call cq again)
  • Thats just one qso in 6 minutes
  • Often takes longer due to misses, and need to
    wait for next cycle to repeat

  • Push buttons for each step in JT65 QSO

JT65a Decode
  • Can be confusing. There is a 13 character free
    form available in place of final 73 message, but
    without callsign, need to look at Hz delta
    frequency to see who sent (e.g. _at_2037, 0130 was
    KE0YI). Better to use the stock 73 message (push
    button answer 4).

Olivia The Magical Mode
  • Robust QRP-friendly keyboard conversational mode
    with excellent resiliency to fading and noise
  • QSOs possible even when cant hear it, or see it
    on the waterfall!
  • Multiple bandwidth/tone format choices available
  • 500/16, 1000/32 most common, 250/8 shown in
    example above
  • Tuning Voluntary channelization per
    band/format e.g. DIAL14074.65kHzUSB -
    AudioCenterMarker 750Hz - Format 500/16,
    (14075.4kHz(Center_Freq)) DIAL14106.50kHzUSB -
    AudioCenterMarker1000Hz - Format1000/32,
    (14107.5kHz(Center_Freq)) DIAL18102.65kHzUSB -
    AudioCenterMarker 750Hz - Format 500/16,
    (18103.4kHz(Center_Freq)) DIAL21086.50kHzUSB -
    AudioCenterMarker 750Hz Format 500/16,
    (21087.25kHz(Center_Freq)) DIAL21152.50kHzUSB
    - AudioCenterMarker1000Hz - Format1000/32,
    (21153.5kHz(Center_Freq)) DIAL28076.00kHzUSB -
    AudioCenterMarker 750Hz - Format 500/16 ,
    (28076.75kHz(Center_Freq)) (see
    http//, http//
  • Expect a lag from signal on to decode start of
    4-6 seconds

Hellschreiber (Feld-Hell)
  • Fax-based teleprinter system, used by the Germans
    during WW II
  • Translated as light writer, result is a dot
    matrix print
  • Unique, in that it is visually-based decode mode
  • Turns out human brain is very good at reading
    text in noise
  • Look for signals below PSK range 14.063-14.069
  • Dedicated enthusiasts love the mode, maybe you
    too? (ref http//
    ub/Home/feld-hell-faq )

  • Analog slow scan TV has been popular on HF for a
    long time. Send/receive GIF/JPG/BMP pictures via
    HF radio!
  • Now high def Digital SSTV is getting lots of
    buzz, thanks to DRM (digital radio mondiale), and
    new software packages like EasyPal (refs
    http// , http// )
  • Want to listen in? These digital signals are
    found in voice part of bands. Try SSTV near
    21.340, 14.230, 7.171 DSSTV near 21.337,
    14.233, 7.173 Mhz

Recognizing signals by sight/sound
  • Lets try a round of Decode that signal

So whats holding you back?
  • Join the thousands of hams using digital modes
  • Enjoy DX with low power and an attic antenna
  • Set aside all the static and shouting
  • Play on the radio without disturbing the rest of
    the family
  • Another way to help in emergency communication
  • Extend your own horizons with new
    opportunities Digital contests, typing qsos,
    digi nets, awards
  • Push your hobbys technology envelope
  • Experiment with new modes, meet new people

Come on in, Join the Fun!
Digital HF Join The Fun!
  • Thank you!