MFSK
Ahh! so that's what the mystery signals were, eh!
by Ernie Mills, WM2U. http://www.qsl.net/wm2u
Please print this article and use it as a hand out at Club talks and lectures

For weeks I received e-mail from all over asking me what that strange noise was that could be heard  on 14.080 most nights! I was completely stumped and could not find the answer until I finally talked to the A.R.R.L. technical department. What we were hearing was MFSK. Actually it was MFSK16, a MFSK variant developed by Nino Porcino, IZ8BLY which he calls Stream. MFSK16 has 16 carriers spaced 15.625Hz apart, operating at 15.626 baud. This occupies about 316Hz bandwidth with a data rate of 62.5bps, or about 80 wpm. However it has built in FEC error correction which reduces the text throughput to about 42 wpm or 31.25bps. My first contact was with Bill, K2ZEL in Florida who, thankfully having the patience of Job, worked me through the QSO. Wow! that is a fantastic mode.  
M
FSK, Multi-Frequency Shift Keying, has it's roots back in 1935 with the development of a system called LMT. A variant, Coquelet was invented in the early 50's, 1957 brought Kineplex and  Piccolo, the later of which was used by the British Foreign office, and even DTMF is a form of MFSK which, as you all know, is widely used today as your telephone Touch Tone.   It's CCIR definition is F1B or F1D if transmitting non-text data. The technical explanation is well covered in FCC Part 47 Rules, paragraph 2.201
I
am not going to get into the theory of this mode in these pages. The idea here is to assist new Hams in the software download, and setup as well as the sound card interfacing needed to achieve a speedy installation while maintaining clean signals. During my MFSK learning curve, I came across some really well written stuff that was easy to read and covered every facet of this mode from it's history to the inner workings of the code. So it is hear that we start!  
F
irst off download the software from ZL1BPU. At the web page, click on Reference Documents. Pan down to the software section, and click on the download icon marked: Latest IZ8BLY Stream version. Click on the .exe file and Stream will install into the C:/program files/stream folder.  Oh! if you upgrade somewhere in the future, it is recommended that you uninstall the old version first. Don't worry about the computer register, this program does not write anything into it and the uninstall routine does not delete the configuration file so all your settings are preserved.
N
ow, before ya! do anything else, please print off the help files. There is a lot of good information here on the configuration and operation.  Now go back to the web site above and print off each of the 6 menu items. Hey! the theory is really fascinating. Finally read the Article that appeared in QST, January 2001, page 33 called: MFSK for the New Millennium by Murray Greenman, ZL1BPU. There you have it! Everything you want to know is in those publications. 

Screen shot of main window

First let us go through some of the features of the main screen. Fire up the program and you will see a screen similar to the above. So! what do we have? The top row is the Menu bar giving you access to all the required parameters to control the software. Then you have a  row of quick access buttons which are really handy. These include clear screen, set volume, and AFC.  The log window is next. This is where you will put in the QSO information. Remember that the Macros use this info so don't forget to fill this out during a QSO. The receive window is next followed by the transmit window. This is where you will type stuff in ready to send out.  Below this is a set of 13 Macro buttons, all of which you can edit.

Tuning a Signal

Spectrogram

Menu showing tuning technique using the waterfall indicator

Operating Frequencies

1.838, 3.580, 7.037, 10.147
14.080, 18.105, 21.080, 24.929
and 28.080 MHz

Use USB above 10mHz and LSB below.

The screen shot at left shows the Spectrum, or Waterfall Display. The distance between the two red lines is 300Hz, similar to the Mark and Shift frequencies of Rtty. These are at 1kHz and 1.3kHz.
Ok, the broad white band is the MFSK signal and the objective is to get this placed between the two red lines. Notice on the lower left side of the signal there is a small white line. This idle carrier is transmitted briefly at the start of each over. Also notice the two gray lines below the red lines. These only appear when you put the curser in the spectrum window. They move up and down with the movement of the mouse. If you place them over the MFSK signal and click the left mouse button, the signal will snap in place between the red lines.
However the MFSK signal has to be within 4Hz of the red line before the ALC will take over. I find that when you move the gray lines over the MFSK signal, if you align the bottom gray line with the idle carrier ( you can tell you have perfect alignment when the color of that segment of line changes color. On mine it changes to Cyan), then left click, it will be perfectly aligned and you will start to see print within a second. This delay is caused by the FEC decoder routine

Configuration
Lets take a look at configuring this software for basic operation. Go to the File Menu click on Preferences and Look at the General Page.
Ok fill in your Call sign, Name, QTH, locator and e-mail address. Now is the time to set the colors of the Tx and Rx screen text and background. Set the center frequency to 1000Hz and hey! remember the Macro buttons, and the CQ button which looked different to all others? yep! well this is where you can Edit that Macro :)
Now click the PTT Port tab, and select the button that represents your active com port.
The Advanced tab is next. It is recommended that you do not change anything on here until you are familiar with the MFSK software. I changed the Waterfall Speed to Normal and made it Logarithmic.
The Tools page is pretty well self explanatory.

With these setting you should be able to get on the air and start having fun

Hardware Requirements
  • A computer with Windows 95©, Windows 98©, or Windows NT©.
  • At least a Pentiumô 60 processor (P133 prefered)
  • A 16 bit sound card that works with windows.
  • A HF transceiver.
  • Sound card interfacing and PTT control as per my Hook-up page.
Using the Macro Buttons
There are 13 buttons at the bottom of the screen which will let you send out pre-written buffered messages. The first, named CQ is edited on the File>Preferences>General page. All the rest are easy to edit. If you right click on any of the remaining 12 buttons an edit window will open and you can change the button name by writing in the small window at the top. In the main window type the message you would like to store in that buffer. There are some special commands called  Metacommands, commands that will allow you to do various things within the buffered message. These include automatically picking up the Others Call sign, Name and RST from the log window. A Time Stamp command is also included. If you click on the word Metacommands above I have arranged for a popup to display a list of these commands. Print them off !

OK! Can you do it?  Yep! I know ya! can.

Don't forget that this software uses the computer sound card and the Radio must be interfaced to the Computer. That is no big deal, just follow the suggestions on my Hook-up web page. Please print off and read the help files. There's a lot of great information in there.
T
he check list below is basic but it should get you up and running in no time. 

  • Download the software from ZL1BPU and install as per above instructions. Simply run the .exe file and it will install itself.
  • Click File>Preferences and hit the General Tab. Fill in your Call Sign, name, QTH, locator, e-mail address and set the center frequency to 1000Hz.
  • Select 'PTT Port' Tab and select the active com port.
  • Write your buffers as required.
  • Turn on your Radio switch the dummy load in.
  • Set the Radio Volume to a comfortable level.
  • Click the 'Set Input Volume' icon and set the slider to about 25%.
  • Click the 'Set Output Volume' icon and set the Volume slider to about 25% and the 'Wave' slider to about 50%.
  • With a dummy load fitted, hit any key and send out a carrier. Adjust the power output so the ALC on the radio is just not reading. It is recommended that you use the same adjustment technique as you do with PSK.
  • Tune to 14.080MHz and practice tuning in a station using the Waterfall Display until you can copy text on the screen. This is discussed above and really needs to be practiced first.
  • As soon as you start typing you will go into Tx. If you put an "*" as the first character in the Tx window you will be able to type your message and/or include a buffer without it automatically going into Tx. To transmit this info hit CTRL T. To end transmission hit Enter and F12 and it will switch to Rx after the buffer is sent. CTRL X aborts transmission.
  • That's it! The rest you will learn on your own. Please read the Help file. It has so much more important information you need to know.
Good luck, enjoy and I hope to see you in there.73 Ernie (WM2U)