Wednesday, June 3, 2009

Session 1 - Summer of Digital Communications Fun

This is Curt Black, WR5J with the Educational Radio Net –
Please stand by for a DIGITAL QST

Send File ALLMODE.wav from KK7UQ (Thanks, Clint)


Starting a Summer of Digital Communications Fun
(and Maybe to Make the Next Emergency More Fun, Too)

First – Intro: Curt Black – Environmental Scientist – Ham for ¼ century – ¼ century ago had a digital node in a packet network that passed traffic all around texas

Also a naturalist – birds and bats and nature in general – Sound Recordist – just finished teaching a class for nature sound recording at the UW.

Schedule – This week – Introduction Then a two week break – I’ll be on a research vessel next week doing geophysics in Puget Sound and the full week after that I’m teaching a workshop on field techniques for bat research in eastern Washington. The 8:00pm timeslot is a very full one if you are doing bat research.

But you blog readers have an assignment for the next two weeks. Download a specific software package, FLDIGI, and get it configured for your soundcard. Also, setup a microphone in your shack. Do it in such a way that as you are monitoring the waterfall, you can see all the sounds in your shack appearing on the waterfall.

After the 2 week break – we'll start with setting the software up and then Acoustic Coupling of radios and computers and work our way through a few modes. Then we’ll move into harware coupling of radios and computers with interfaces. These interfaces can range from very simple ones for a few bucks to $100 for a Tigertronics SignaLink USB. If you want to keep going you can go up to a $369 US Interface Navigator - Lots of choices.

As another potential assignment, you might want to start working on your interface over the next 2 weeks – One plan is in this months, June 2009, QST on page 30 – a nice article by Skip Teller- KH6TY and a $5 offer for the circuit board for the project. If you are considering the TigerTronics product, I just talked to them at SeaPac and the 4 week backorder on the SignaLink USB interfaceis a thing of the past. They say they are current with orders and hope to remain so.

We’ll revisit some of those modes we were experimenting with through acoustic coupling and use our hardware interfaces and see if that improves copy on some of the more sensitive modes. Then we’ll try some other software, week by week working our way through different modes or packages. I’ll put complete instructions on the website and if folks have trouble, my phone number and email will be on there as well. Then we’ll set up of the software for WSPR, the Weak Signal Propagation Reporter, WSJT a group of modes by Joe Taylor for Weak signal work terrestrially or via moon bounce that inlcudes JT65A used on HF and just exquisitely sensitive.

Then if there is interest, we could visit some of the image transfer modes like EASYPAL – a mode that uses Digital Radio Mondiale or DRM to send the contents of an image file with repeats of any blocks containing errors so the picture comes through perfect – picture perfect if you like. We might even try some digital voice since the software is out there and very few people are using it. FDMDV, Frequency Division Multiplex Ditgital Voice, is a replacement for WinDRM and DRMDV - programs that just like EasyPal are using the Digital Radio Mondiale encoding technique.

Not to be a slave to things digital, I have greatly enjoyed some analog slow scan television (SSTV) in the past. A Japanese ham, Makoto (Mako) Mori has a series of applications MMSSTV and MMRTTY among them availabe at

This Training Program and its Congruence with the Overarching Purposes of Ham Radio
Review of §97.1 Basis and purpose.
The rules and regulations in this Part are designed to provide an amateur radio service having a fundamental purpose as expressed in the following principles:

We should be able to do just about all of this during this summer...

Whats Digital?

Definition of a digital mode – for us, let's say, a mode made to be generated by and decoded by machine – not typically intended to be decoded by ear –

What about CW? It was originally intended to be machine or visually read, but operators found they could copy the messages from the sounds of the equipment – so now it is by ear with practice. Is it digital – go onto a discussion listserv and argue for either position – you will discover people of great passion on both sides (this may be true of all topics in ham radio).

When you get to high speed CW for meteor scatter work , it is particularly true it is only readable by machine. Several of the other modes more traditionally considered digital are also at least partly readable by ear - RTTY, esp. calling CQ, is very distinctive.

For later we will go through all the words in this definition, but for now, CW is a three symbol code with source coding (variable length alphabet, like varicode) with soft decision coding, and mild FEC (operators interpretation of the code based on S/N) and some convolutional coding with soft decisions (matching characters received against patterns / words.

Decoding Digital Modes
If they are meant to be decoded by machine what do you need to do the decoding? Luckily some very generous and clever people have written some amazing software for decoding a wide range of digital modes.

Some programs just specialize on one mode.

Like Pawel Jalocha SP9VRC and Nino Porcino IZ8BLY MT63 Terminal (from

or DIGIPAN by Skip Teller for BPSK-31 and QPSK-31 and 64 from

Often it is the introductory package that showed the world what the mode could do and made the mode popular, but eventually many modes are incorporated into programs that combine many modes and offer great flexibility with just one set up of the hardware and one user interface.

By far, the most wide ranging piece of software currently available is MULTIPSK.

Contrary to the name, it does far more than decode just PSK modes, and in fact, it decodes more different modes or protocols than any other package. Check out the author, Patrick Lindecker, F6CTE – and his (english language) website at for MultiPSK 4.14 and a listing of the incredible range of modes supported.

Patrick is updating his code and adding modes nearly every week – it is amazing. The only downside is that the user interface is pretty daunting and the documentation is occasionally hard to decipher (although far better than if Patrick had reciprically insisted that I write the documentation in French). A very complete version of the program is free. For a donation, registration will activiate other desirable features.

The other end of the spectrum on the user interface scale is Ham Radio Deluxe (HRD) with the companion program DM780 for the digital modes. This is the most polished piece of software I believe I have ever seen. While Simon Brown, HB9DRV, has not expanded the modes decoded to the range of those in MultiPSK, the user interface is very polished and the software works like a dream. Its only drawback is a very comprehensive suite of capabilities. These include logging functions, web lookup and spotting and many more that can make the package somewhat daunting to a first time user. HRD can be found at and the companion digital mode decoding package, DM780 is at

MixW has a long history . It is a package with many features which requires a $50 payment to keep the program functional after an introductory period. This was pretty standard in 1996 when it was introduced, but there are some great programs out there in competition with for free. It went from February, 2007 to January 2009 without updates, but fairly recently was updated with several new modes and features. If you are a MixW user, you are probably familiar with the help files available from For many years MixW was the most feature rich and fairly simple piece of software for digital modes, but I think it has been supplanted by some of those already mentioned and is particularly true for the package I'll discuss next.

The NBEMS Suite of software, Narrow Band Emergency Messaging System, has been developed to fill a need for a fairly concise set of features and modes in a package that is well designed, easy to install, set up, and operate. It meets each of these design goals very well. It is free for downloading from On that page, you will find Linux versions, and versions for Windows 2000, XP through Vista.

A Pennsylvania Radio Amateur Emergency group has assembled instructions for downloading, installing, configuring, calibrating, operating and enhancing the NBEMS software. Find them at and follow their sequence. Hopefully, that doesn't sound daunting. They have nicely put the information into bite sized pieces. This coupled with the clean and well organized user interface make this my current sofware choice for quickly getting people up and running on digital modes.

What Modes are out there? (limiting ourselves to machine readable modes)
(in later weeks we’ll take these one by one and look at how the information is encoded and what the strengths and weaknesses are of each.)

In rough order of “popularity”:

By a landslide, PSK31 – Phase Shift Keying – with the flavors, Binary Phase Shift Keying BPSK-31, Quadrature Phase Shift Keying, QPSK-31, BPSK- 63, QPSK-63, BPSK- 125, QPSK 125, BPSK-250, QPSK-250

RTTY – 45 baud, 50-baud, 75-baud

Olivia – several flavors from 250 to 1000Hz bandwidth and with from 8 to 32 tones

MFSK (Multi Frequency Shift Keying) which varies from 4 to 64 tones

DominoEX (4,5,8,11,16,22)

Hell modes (Feld Hell, Slow Hell, Feld Hell 5, Feld Hell 9, FSK Hell, FSK Hell-105, Hell 80) The Hellschreiber or Feldhellschreiber was a facsimile-based teleprinter invented by Rudolf Hell in the 1920s. It has since been emulated on computer sound cards by amateur radio operators; the resulting mode is referred to as Hellschreiber, Feld-Hell, or simply Hell. "Hellschreiber" translates into English as "Light Writer," "Bright Writer," or "Clear Writer," and is a pun on the name of its inventor (Hell (the adjective) is German for "light," the adverb is "bright.") from Wikipedia

MT-63 (500, 1000, 2000 Hz bandwidths)

Thor (4, 5, 8, 11, 16, 22)

Throb (1, 2, 4)
ThrobX (1, 2, 4)

Chip 64 a phase shift keying application that utilizes some spread spectrum methods

And a Universe of Others…

WSJT 7.03 Latest release by K1JT, Joe Taylor of Princeton

WSJT Protocols inlcude the following modes

FSK441 for meteor scatter

JT6M for ionospheric scatter

JT65 for EME at VHF/UHF, and

JT65A HF skywave propagation Frequently heard at 14.076
JT2, JT4,

Joe Taylor also wrote:
WSPR: - Weak Signal Propagation Reporter
I’ve used 1 Watt and been copied in Singapore, New Zealand, Australia and South Africa
Check out the site for the database of propagation reports. Listen on 10.1387usb, 14.0956usb. As people begin to trust the ionisphere more and more with this mode, you see increasing numbers of entries in the database for 0.1 and 0.01 Watt signals.

PC-ALE - The Automatic Linking and Embedding protocol for testing the ionisphere, finding a path, connecting stations and exchanging information. The program listed is a pretty dense read, steming possibly from its military background, but Patrick Lindecker in MultiPSK has taken the best of ALE and developed a new mode ALE-400 with a narrow bandwidth and some nice keyboard to keyboard features. I suspect his mode will be incorporated into other packages soon.

APRS - the Automatic Position Reporting System - a flavor of packet radio which is probably a summer of adventure on its own. Once we have the interfaces working for our radios and computers, the addition of Packet Engine by SV2AGW, with some great help files and setup instructions from Ralph Milnes at

And if you are doing packet, you might as well be setup for message traffic for the next emergency, so PacLink should be on your radar. Particularly with the addition of a new sound card digital mode, Winmor which is undergoing testing right now. As part of the winlink system, PacLink can be found at After testing, Winmor will be fully integrated with PacLink and shows promise for being a sound card replacement for previous hardware solutions like Pactor which was propriatary and pricy for the average ham.

The really good news is that whatever interface we set up for any of these digital modes opens up just about all of them (there is a caveat for the topic of Rig Control and antennas - the ALE system likes to roam around in the various ham bands listening and occasionally transmitting "soundings" and that can't be done if your computer isn't communicating with your radio and if your radio can't switch to various bands and find a good antenna waiting there. The good news is that you don't have to do ALE on multiple frequencies - you can tell it stay on one band, or even one frequency. While this defeats some of the intended benefit of ALE, it lets us experiment a bit - which I'm hoping is what ham radio is about.

Steps for getting setup with NBEMS
(I'll follow up with transfering the Pennsylvania instructions to a blog entry)

Download the file for your machine from:
There are 2 windows versions and a Linux version, and I think there is a OS X version on the original W1HKJ page, but not the link
What I know about NBEMS, the Narrow Band Emergency Messaging System, I learned on the Pennsylvania Situation Report website:

And Specifically the NBEMS portion of the site:

Assignment 1 – go to the BLOG (link from the PSRG site to avoid the long blogspot address if you like ) and follow the instructions for downloading the NBEMS software.

The only program you need for awhile will be FLDIGI -but just get everything that comes in the zipped package – WRAP, FLARQ, FLDIGI and some utilities like a sound card calibration piece called CHECKSR (ssome of those may not be in the same zip file). The zip file also contains CYGWIN1.DLL - follow their instructions to make sure your really only have one copy on your machine and all will be fine.

If you are willing – keep going through the PA-Sitrep site instructions and download their macro set – . Also continue to the bottom of the page for the Definitions and Preferences files - note to save them in a different location from the Macro file

Finally, think about what sort of interface you might like.

It could be none, but if you are willing to do a bit of building or buying, your horizons are unlimited. We will spend several weeks messing with just acoustic coupling – so no pressure.

We are at an amazing time for digital modes. There is phenomenal computational power in our computers and we now have software that can do stunning things with weak radio signals. This is perfect for this difficult phase of the sunspot cycle. It is also nearly ideal for people in situations where an “aluminum sky” of antennas is not an option.

We are about to get some very effective ways of automating the identification of a large number of digital modes. This has been one of the most daunting things for hams wanting to move beyond PSK-31. Soon HRD/DM780 will join FLDIGI and MULTIPSK in automatically scanning the audio passband for the unique sound of Reed-Solomon identifiers for each digital mode and submode. In this way your rig can automatically recognize the mode, switch to decode it, move it to the center of your audio passband, close your filters down around the selected signal and decode it for you. We live in some great times. For more information about the automated identification of digital modes, since I may have mangled the concept during the session on the repeater, please check out Patrick’s description at

I’ll see everyone on Wednesday June 24 at 8:00pm – hopefully recovered from any bat bites and sea-sickness.

Curt Black –
WR5J – West Seattle, Washington, CN87tn
Download and install instructions will follow in the next post

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