Category Archives: Ham Radio

Amateur (Ham) Radio (Yaesu FT-991A) in Digital Mode (FLDigi) on Mac OSX (Yosemite)

I picked up transceiver radios several years as a new hobby, well OK the year was 2008. The impetus was really the Katrina storm event, seeing all communications grid disrupted except for radio and satellite communications.

I have no satellite equipment and thought that would be too specialized and limited in usage. I wanted a general purpose way to communicate during normal and emergency times that could reach most of the population in the USA. Naturally, I gravitated to Amateur Radio, commonly known as Ham Radio. Ham Radios can communicate globally, and as I found out, surprisingly they can also communicate via satellite.

You don’t need a license to get a radio and listen to Ham Radio, but you must have a license to transmit using Ham Radio. There is an exception that allows the use of Ham Radio without a license in life/death emergency situation to call for help.

My license is categorized as a “General” license. Simply put it allows me to use a larger amount of frequency than a “Technician” might have (which is an entry level license). “Extra” license gives you all the frequencies Amateur Radio operators may operate in.

I made my first contact with voice a long time ago. From Seattle,WA area to Sacramento, CA. It was a tremendous feeling to have that freedom to talk with someone a long ways away and free too!

My first contact suggested I try digital mode communications. That is where the voice signal is converted into a digital signal, transmitted, received, and decoded back to a voice signal to be heard by the receiver.

The advantage is lesser power is required to communicate. The disadvantage is it’s comparatively slower than speech. There are many digital modes in use today but the most popular is PSK31.

I tried it for a while but could not make a good contact with anyone. At the time, digital mode was achieved with a string and tin cans …

I’ve since sold my initial rig (that’s what radios are called in Ham Radio) and purchased a rig that has more capabilities and has an audio receiver & transmitter board in it. I no longer have to create wires from the computer to the radio to achieve digital mode.

Equipment configuration:

  1. Yaesu FT-991A transceiver radio
  2. A BuddiPole used vertically, aka BuddiStick (40m: 2 regular arms then 2 regular coils with no taps, 2 regular whip sections out, then tune either with the radio’s internal tuner or with MFJ-269 antenna analyzer)
  3. MFJ-269 antenna tuner. I connect this to the end jack that is to connect to the radio. I use a duplexer, do not connect to the jack prior to the duplexer, the results are misleading. I set the tuner to 7.000 MHz (or whatever frequency you like) and look at the SWR meter. Pull or push on the whip section to lengthen or shorten it. The longer the whip, the lower in frequency you go and vice versa. Anyway tune the whip section until you get an SWR reading of 1.5-3. After this I let the radio’s internal tuner tune it more if necessary
  4. or an alternative is to hook up the antenna and use FT0991A’s internal tuner.
  5. FLDigi software to perform encoding and decoding of the digital signal from the radio
  6. MacBook to run FLDigi on

The radio and FLDigi need to be configured.

FT-991A radio SETUP using MENU/SETUP button:

BEFORE ANYTHING ELSE, CONNECT YOUR ANTENNA TO YOUR RADIO. Accidentally transmitting without an antenna could ruin your radio.

This enables the radio control:

  • 031 cat rate  9600bps
  • 032 cat tot 100 msec

This enables data communication (use DATA-USB mode)

  • 059 cw freq display DIRECT
  • 062 data mode OTHERS
  • 064 other dsp ssb 1500hz
  • 065 other shift ssb 1500hz
  • 066 data lcut freq OFF
  • 068 data hcut freq OFF
  • 070 data in select REAR
  • 071 data ptt select rts
  • 072 data port select USB
  • 073 data out level 70

This enables data in FM mode (use DATA-FM mode)

  • 074 fm mic select REAR
  • 075 fm out level 70
  • 076 fm pkt ptt select RTS
  • 077 fm pkt port select USB

You also need to set the DT MAIN configuration. Press F-MList button, the press FWD on the display until you see DT MAIN. Tap it and then use the knob on the bottom right of the display, turn it to 4 first. Now set the METER setting to ALC, it will show ALC value on the top of the display, As we turn the DT MAIN knob higher, we want to see ALC only a little, turn it just until you see ALC, then turn it back one step.

Before connecting the FT-991A to the Mac, you must install USB drivers on the Mac first. These can be found at:

Once the driver is installed, you can connect the USB cable.

When you are configuring FLDigi and asked for a Device in RigCat, use the serial port named /dev/cu/SLAB_USBtoUART.

FLDigi configuration:

When you first run FLDigi it shows an FLDigi configuration wizard which walks you through the setup steps.

If you’ve already stepped through that and wondering how to run it again, whoops there isn’t a way to do so. There is actually, just run Terminal which by default opens in your home folder, and run this command to be sure cd ~. Once you’re in your home folder issue this command rm -r .fldigi that should remove the configuration folder. Close FLDigi and reopen it and the wizard should appear again.

On the other hand you might just follow the steps below to configure FLDigi.

First, fill out the Operator form from menu item Configure , then UI, then Operator, provide information about the operator, it is used for digital mode. These are optional for voice and CW operation. It is however strongly recommended for digital mode. Of specific importance are:

  • Station QTH, provide your geographic location here. I live in the vicinity of Seattle, WA. USA. So I use Seattle, WA.
  • Station locator using grid square coordinates. You can find where you are and provide the locator using this site by David K2DSL:
  • Operator Callsign. This is your callsign that was assigned when your license was issued to you.
  • Antenna. This is optional, but I like to provide it as information.

Second, we configure our Audio section. You can get here from menu item Configure then Sound Card. Set checkmarks for PortAudio and Device Supports Full Duplex. Then select USB Audio CODEC for both Capture and Playback settings.

To control our radio using the FLDigi software, we select the Configure menu item, then select Rig Control menu item, and then you’ll see the screen shown below.

Enter the values marked by red boxes as shown. Make sure you click Save.

For Rig Description file, get the file from here:

and place it in your ~/.fldigi/rigs folder, select it for Rig description file.

If you had the USB cable plugged in earlier, unplug it now, this is to reset the serial port driver on the Mac. FLDigi will sometimes not connect to the radio and you’ll see the frequency display mismatched.

  • Close the FLDigi application.
  • Connect the USB cable from the radio to the Mac.
  • Power on the radio.
  • Launch FLDigi.

If all went well, the frequency display on your radio should match the frequency display on FLDigi.

Final step is to choose the Operating mode. Use menu item Op Mode, then PSK, then BPSK-31.

The frequency that is commonly used for PSK in the 40m band is 7.080.15 MHz USB in the morning USA Pacific time. When you tune around there, you’ll hear a bunch of squealing noises that PSK31 makes. You’ll also see yellow streaks on the waterfall display. A yellow streak is one conversation going on.

Click your mouse on one of the yellow streaks and FLDigi should decode and display the conversation.