Recently I purchased a XGGCOMS Digimode-3 interface in order to take a step in to a digital world of FT8, JT9, PSK31 and other “egsotic” digital modes of work.
I have second hand Icom 706MKII that works well and I thought buying a digi interface will be a good reason not to use it just for SSB modes of work but also trying to gain knowledge about new ways of usage of our ham equipment.
After arrival I read manual published on seller’s site. It quite well (maybe it need some additional text inside) describe setting of Digimode-3 under Windows OS, but sadly there is no any written word or video record how to do it under Linux OS , especially with Icom 706MKII radio :)
My first contact was so disappointing because no matter how much I tried , suggested ALC level stayed around 5-6 squares and even I managed to work some station with such a setup.
There must be a way to do it under Linux, in my situation Ubuntu 18.04. And there is a solution. I do not know how much people who work HAM under Ubuntu or other Linux based system are experienced but for me I may say (middle experienced user) this OS is still sometimes a mystery. You do not see it on the menu bar or program bar, then you do not know that it exist :)
The fastest way to set digimode-3 is to do it with ALSAMIXER.
Note: My Ubuntu is set to work with gnome meta-city extension (oldie but Goldie) so this explanation is for this environment. For new Ubuntu 18.04 environment it is almost the same (sidebar).
1. Open with ctrl+alt+t terminal window and at the prompt write/start alsamixer.
- Choose proper audio device (C-Media USB set) with pressing F6 and select it from menu.
- In order to see all possibilities press F5 (View All).
Picture 1. Selecting Digimode-3 in alsamixer
- Moving around given settings is possible with your cursor keys left/right arrows. Increase/decrease of values is set with up/down arrows.
- Go to Headphones.
- With Q/Z keys change of balance is made for left channel and with W/X keys you can balance right channel.
- Set to lowest possible value for both channels (around 33%) .
Picture 2. Help menu with keys
Note: Do not close or exit alsamixer and terminal window.
2. From drop down menu Applications-System tools-Preferences-Settings-Sound select “Digital output S/PDIF – Audio adapter” . Set value of balance to be in the middle, and mic level should be minimum. Audio level should be at minimum or near minimum.
- Start WSJT-X and wait to load. From the right side, set power meter (gliding up-down bar line) to the middle or upper to ¾ of the bar.
- Set your radio to 50% of it power (I set mine to 50W for start) and get good SWR at 7.074 (FT8) or other work frequency of available digi modes.
- Set on your radio ALC level to be displayed.
3. In WSJT-X select option TUNE and get back to terminal window and alsamixer. For now, your radio should not transmit anything, because VOX level is not enough to activate TX.
- With Q/Z keys increment audio level ONLY to LEFT channel while right stays at it present level of 33%. Around 80% you should hear relay triggering TX on your Icom. Now it is transmitting and
ALC level should be absent (no ALC level readings on indicator).
- With W/X keys slowly increment ONLY RIGHT channel until you see only one bar of ALC level indicator. When you see it, get back one step lower. Now you have set best signal for digital work.
- Get back to WSJT-X and try to move power meter to higher position and get readings on your SWR/POWER meter. At present settings you should run around 20-30W of power without any ALC activation or distortion of signal.
Picture 3. Properly set of alsamixer and power meter (background)
- Deactivate TUNE option from WSJT-X.
- Close alsamixer (ESC key) and terminal window.
Your radio now is just one step from complete settings for digi work.
Note: If above settings (step number 3) did not trigger relay for TX, then slightly increase power meter in WSJT-X and try again will it trigger TX relay. Find the balance for trigger of TX relay ONLY with your LEFT channel and power meter. DO NOT TOUCH or set right channel, it is already set on it best value (for now). You can also try leaving your left channel value just below red zone and only try with power meter from WSJT-X. Changing values of power meter is best to be done with your mouse scroll wheel or touch pad trackball option.
4. Set MIC level (Microphone audio adapter) for good receive of signals. Suggested minimum signal level should be 30db (WSJT-X suggestion). Anything in the green zone is good signal value.
Picture 4. Setting MIC level for best receive signal
That’s all folks.
Now your digimode-3 is properly set to work with Ubuntu or other Linux based system.
Small note for authors of WSJT-X:
Increase/decrease of power in WSJT-X result with not so smooth change of output power like running under Windows. On my computer (Asus 1015PEM Intel Atom N550 dual core) there is some response delay of around 0.5 sec , difference between change of power and command reaction of the radio. Take note about this when changing power to new values.
73 DE PETRIKA
Z34PEC
KN01qx
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