Configuring fldigi via RIGblaster Plug & Play to an ICOM IC-718
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Fldigi to IC-718 -
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IC-718, Rigblaster, and fldigiClick
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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
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
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
West Mountain Radio
RIGblaster Data Jack plug and play,
to work with fldigi on Linux, to an ICOM
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
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"
- 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
- 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...
To confirm success, the frequency display in the main display of fldigi
will now track any changes you make to the frequency knob on the
- 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
- 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
- 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.
Any problems at this point are in the Rig setup in fldigi, so head back
there to debug.
- 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
- You'll also hear the PSK31 transmit modulation on your PC's
- 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
- 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
- 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.
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.
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.