Configuring fldigi via RIGblaster Plug & Play to an ICOM IC-718

IC-718, Rigblaster, and fldigi Click for larger version with detailed notes on components

Hams have known for a century how much fun it is to use narrowband digital communications to punch through atmospheric conditions and make a little power communicate over very long distances, sometimes literally around the world. One of the fun ways to do this today, especially for newly minted hams without International Morse code skills, is to use a computer to modulate the signal and do the decoding for you.

What is fldigi?

One of the best programs out there for computer modulation is fldigi. It is free, open source software. Ultimately it does a lot of what Internet chat does, but you can do it on battery power, and without an Internet, or wires. Fldigi visualizes the signals across the audio frequency space over time using a colorful waterfall display. It has a built in software modem to transmit and recieve audio using your computer's sound card. It has several ways it can assert a push-to-talk (PTT) signal to cue your transmitter. If your transceiver supports a data connection it can also communicate frequency settings between fldigi's screen and your radio.

With all these neat features, the configuration of fldigi can be confusing. This article came about because I have figured out the settings for the last time - I want to park my notes where I can find them again, and share them with you, dear reader.

Hardware and Software Basics

There is a whole plethora of hardware available for hooking serial, USB, and sound card audio up between your PC and your radio. I've played with a Signalink USB with its built-in soundcard, but today I'll focus on configuring a West Mountain Radio RIGblaster Data Jack plug and play, to work with fldigi on Linux, to an ICOM IC-718.

First off, make sure your sound card works correctly with Linux. I'm using a software distribution, Fedora 13, based on the Gnome project and pulseaudio. Right click on the little speaker in the upper right corner of the gnome panel, and select Sound Preferences. This will start up the gnome volume control applet.

• Click on the Sound Effects tab. Set "South theme" to "No Sounds". Turn off "Enable window and button sounds"
• Click on the Hardware tab. Click on the audio device you will use to connect the Rigblaster. I usually click on Internal Audio. Set the Profile: to "Analog Stereo Duplex". Click on Test Speakers and use that dialogue to test that you can hear noises from Front Left and Front Right. Return to Sound Preferences.
• Things you can tweak if you can't hear anything: 1) Note the 'Output volume' slider at the top of the Sound Preferences, you may need to adjust that. 2) Click on the Output tab and select the sound output device and Connector (I use "Internal Analog Stereo" and "Analog Speakers" connector.
• Leave Sound Preferences open, we'll be back.

Hook up the RIGblaster Plug & Play

Now hook up the cables per manufacturer's directions. Special notes:

• CI-V rig control cable (optional): attach the stereo plug end (three conductors) to the Rigblaster "RIGCTL" jack. The mono plug end (two conductors) plugs into the jack on the back of the IC-718 nearest the edge.
• The blue Rigblaster "AUDIO OUT" plug goes into MIC/LINE on your PC.
• The green Rigblaster "AUDIO IN" plug goes to the HEADPHONE jack on your PC, but leave it disconnected for now.
• The USB cable goes into any available USB port on your PC or on a hub - it does not need to be high speed. If you use a hub I recommend a powered hub so that the Rigblaster gets the power it needs.

Turn on your IC-718 and tune to where the warbling sounds of PSK31 signals may be heard. This morning, setting the mode to USB and tuning to 14.070.00 is yielding a great signal. Note your AF gain setting is for your ears' pleasure alone - the data jack provides an audio signal that is constant gain.

Install fldigi and Configure Audio Input

Install the fldigi program. It's in most package repositories for standard distributions, so select it from your package manager graphical tool and install it, or for example on OpenSuSE type 'zypper install fldigi' or on Fedora 'yum install fldigi'.

Start up fldigi.

• In the Configure->Operator... menu, enter your license and personal info. Press save.
• In the Configure->Sound Card... menu, select PulseAudio.

The waterfall should start displaying signals as yellow streams flowing down the display with red centers, on a blue background. If you don't see this, then

• go back to the Gnome Sound Preferences dialogue described earlier and click on the Input tab.
• Select an audio device and connector for sound input.
• You should see the signal level in the bar graph, and
• adjust the Input volume so that the loudest PSK31 signals almost max the bar graph output, but do not light up the top one.

Configure Push-to-talk (PTT) and Hamlib

Hook up your IC-718 now to a dummy load - we are about to test things that touch PTT and Transmit.

Head back to fldigi. In the main screen click through Configure -> Rig Control...

• In the Hardware PTT tab set 'Use seperate serial port PTT', set Device to '/dev/ttyUSB0', click 'use RTS', and hit 'Initialize'. This will set up the RS-232 RTS signal as your PTT for the Rigblaster P&P.
• RigCAT tab: make sure Use RigCAT is NOT checked.
• Hamlib tab: click 'Use Hamlib'. Set Rig to 'Icom IC-718 (Beta)'. Set Device to '/dev/ttyUSB0'. Click Initialize.
• Click Save

If you had any problem with that, make sure your CI-V cable is installed correctly (see above) and make sure your IC-718 is set to the default CI-V configuration:

• Go to the initial settings menu on your IC-718: Turn off PWR, hold down SET and punch the PWR button. Use the UP button until you get to the CIV settings.
• 'CIV BAUD' set to 'At'
• 'CIV ADD' set to '5E'
• 'CIV TRN' set to 'on'
• 'CIV 731' set to 'oF'
• Turn off PWR, Turn on PWR

Configure Audio Output

Now we know we are getting input and rig control is working, so it's time to work on the output path.

• Connect the IC-718 up to a dummy load if you haven't already above (you have been hanging on every word, haven't you?)
• Disconnect the output audio (green Rigblaster audio plug) so you know that no modulation is going to the IC-718 for now.
• Set the IC-718 output power. For testing into a dummy load, I like to set power out to about 30 watts. On the IC-718 Hold down SET until RF PoWER is displayed, then spin the knob until it reads 30, and press SET again.
• In the fldigi main screen click on TUNE or T/R - these are toggle icons which will start or stop transmitting.
• Look for PTT: the Red light will show on the RIGblaster, you'll hear the click of the relay in the IC-718, and TX will show in the IC-718's display.
• You'll also hear the PSK31 transmit modulation on your PC's Speakers.
• Use the Gnome volume control to set your PC audio out to about 80% full volume.
• toggle TUNE or T/R again to turn off transmit.

Transmit Settings, into a Dummy Load

Now PTT and PC speaker out are working, we're ready to modulate the audio going into the transceiver.

• Make sure your IC-718 is connected to its dummy load, not your antenna.
• Press the IC-718's SET button momentarily to display PO (Power)
• Plug the RIGblaster AUDIO IN (green plug) to your headphone jack.
• Click TUNE or T/R in fldigi. You should see a few watts being transmitted. If not, adjust your PC speaker volume until you see some watts going out.
• Press the IC-718's SET button momentarily to display ALC (Automatic Loudness Control).
• Reduce PC Speaker output volume until ALC goes completely to zero. This step is essential to providing a clean, 31.25Hz wide output signal that doesn't drown everyone else out on the entire 3 kHz wide PSK31 band!

After following all the above steps, you now have input audio correctly adjusted, rig control, PTT working, and modulation out of your PC correctly adjusted for producing clean PSK31 signals at maximum power.

Tuning up with your Transmatch

Next we'll tune up on the real antenna.

• Connect the IC-718 up to your antenna
• Be certain you will produce a clean narrow signal and are not overdriving your PC speaker out signal (ALC reading is at zero, see adjustments above)
• Select an appropriate output power. Generally you don't want more than about 5W coming out of your antenna for local communications up to 100 miles, about 15W for cross-continent, or about 30W for intercontinental. Remember to go light, so your signal doesn't interfere with your neighbors.
• More to the point on output power: On your IC-718 hold down SET until RF PoWER shows, dial the power, and press SET to save.
• Watch for a quiet spot on the waterfall for 30 seconds or so.
• Click on the quiet spot on the waterfall, so your transmissions won't stomp on anyone else.
• Hit TUNE and tune your transmatch.
• Hit TUNE again to stop transmitting.

Et Voila!

Now you are all set up for using fldigi on Linux through a RIGblaster Plug and Play to your IC-718.

After writing up these instructions I sent a CQ and was hit right back from a nearby neighbor, and we logged a delightful contact.

Good luck! You can reach me at kn1x (at) arrl.net if you have any questions. Feel free to browse my general ham radio page or my personal home page.