March 13, 2012

Join the "CWTD Yahoo Group" for email discussion in between our weekly sessions by clicking here.

Introduction to the Digital Modes"

Ever wonder what all those funny signals (beeps, boops, buzzes and musical tones) were on the bands as you tune around? Sure, you figured they were "digital modes", but which ones, and for what purpose were they is still a mystery.

In this week's session we'll overview many of these (numerous) digital modes and chat about their strengths, weaknesses and general uses in our ham bands.

Further, with the simple guidance we'll provide, you should be able to connect your rig's output to the computer sound card and "read" just about any signal that's on the air!

~George N2APB & Joe N2CX

Audio Recording ... (Listen to MP3 recording)

Text Log ...

<20:00:08>"Chris - w0anm": I ordered a Raspberry PI,  due for delivery on May 15.  Looks pretty cool.
<20:29:45>"Terry WB4JFI": multitone?
<20:32:14>"Joe N2CX": MFKS Multiple frequency shift keying
<20:34:06>"Ray K2ULR": Hellschreiber or Feldhellschreiber is a facsimile-based teleprinter invented by Rudolf Hell.
<20:35:54>"Joe N2CX": Packet - FSK with a packed protocol for message transmission
<20:36:26>"Joe N2CX": Packet higher data ratess are PSK
<20:36:42>"Terry WB4JFI": Packet (AX.25) was never designed for HF
<20:40:53>"Joe N2CX": ALE sends probes on multiple bands to see which frequencies are proper for establighing communications
<20:47:16>"Rick K3IND": JT65 a spinoff from moonbounce communication.
<20:49:46>"Terry WB4JFI": 192k
<20:50:02>"Terry WB4JFI": 48-96-192k sample rates are pretty standard
<20:52:22>"Joe N2CX": What if you don't have RS232?
<20:52:37>"Terry WB4JFI": Skip Teller
<20:53:15>"Terry WB4JFI": Skip lives here in the Charleston, SC area.
<20:53:19>"Ray K2ULR": CocoaModem is popular for the Mac.
<20:55:51>"Terry WB4JFI": Skip designed an interface (in QST?) that does not need RS232 for PTT.  He generates PTT from detecting transmit audio tones (I think).
<20:56:45>"Rick K3IND": and it will blow your final amp!
<21:02:12>"Joe N2CX": you can get audio samples to id xmsn types from
<21:04:27>"Lee KM4YY": First time listening and am totally amazed.  Cannot remember how to talk, but thanks for your contribution to our hobby.
<21:05:29>"George - N2APB": To get started easy:  Download DigiPan, take one patch cable from your rig and plug into your sound card!  DigiPan auto-decodes all the (PSK31) signals in the band and you see the conversations simultaneously.  Lots of help on the bands for DigiPan.
<21:06:10>"Terry WB4JFI": The Skip Teller no-RS232 (or usb) sound card interface is in the March 2011 QST, page 35.
<21:06:17>"George - N2APB": ... it's great!
<21:06:30>"Ray K2ULR":
<21:08:04>"George - N2APB": Gentleman's agreement for where digital modes are on each band.  Google on "digital modes band plans" to see these usual frequencies {thanks Milt]
<21:09:05>"George - N2APB": Can even use a live audio connection from the rig to a mic on the computer. [[Tnx Ray]
<21:09:50>"Lee KM4YY": MT63 is used daily by Navy MARS.  Can audio couple it without trouble also.
<21:10:05>"George - N2APB": MultiPSK for Windows.  Elaborate and very comprehensive.
<21:10:25>"Milt-W8NUE": Band Plans--
<21:13:21>"George - N2APB": ARRL Digital Handbook ...different from VHF Digital book?
<21:13:49>"George - N2APB": Definitely not limited to just Windows digital mode programs.  Can run on Linux and Macs.
<21:13:58>"Curt WB8YYY": ARES groups in Maryland often use FLDIGI for VHF even over repeaters - try some google research!
<21:14:29>"George - N2APB": FLDIGI versions available for both Windows and Linux.  Also on a PocketPC (Voijcz)
<21:15:15>"Terry WB4JFI": George:  a MOST EXCELLENT presentation!  You spent a lot of time and work getting the support information put together, it looks really good.
<21:16:55>"Lee KM4YY": Wonderful program!!  Glad I decided to start tonight.  73 de Lee
<21:17:02>"Ray K2ULR": The about to be released KX3 from Elecraft has RTTY and PSK31 built into the rig.
<21:18:32>"Dennis W5KQF": Great program -- thanks so much.  73, Dennis
<21:21:38>"Ray K2ULR": KE7SCH has just today released a PSK31 app for iPhone, iPad at the Apple site.

Session notes ...



ARRL HF Digital Handbook, 4th Edition ...  Available on-line at …
Digital Technology For Emergency Communications Course …
VHF Digital Handbook …
G4UCJ website …
Steve Ford, WB8IMY … Inspiration, championing and contributions to this presentation
NUE-PSK Digital Modem … “We don’t need no stinkin’ PC!”    (W8NUE, N2APB, AD7JT)


Back to Teamspeak Home