Announce: experimental CAT/DAX clients for Linux

I’ve been running nCAT and nDAX on KUBUNTU 20.04 for since September with no issues, and I’ve made more than 700 confirmed contacts with FT8.

I’ve successfully got cat control working on fldigi with the set up with Hamlib NET rigctl using similar config to WJSTX.

I’ve not figured out the soured card config tho- I’ve tried PortAudio but don’t see flexdax.rx or flexdax.tx in the capture/playback option drop down like I have in WSJTX. I’ve searched google for PulseAudio - if that is the correct option not sure what to put in the parameter box.

Thanks for any help!

73, Chris - WX7V

@Chris WX7V for fldigi, select PulseAudio, leave the "server string" box blank, and hit okay. Then use a mixer app (pavucontrol is one, but you might already have a suitable one hiding behind the volume control button on your taskbar) to set fldigi's playback stream to flexdax.tx and its capture stream to flexdax.rx. PulseAudio should remember the setting so that in the future fldigi will get those devices by default (as long as you start it while nDAX is running).

This is fldigi's issue for not having a UI to select PulseAudio devices, but fortunately it's an easy enough one to work around.

Very glad to hear about your success with wsjtx.

I am using a Flex 6700 along with a Raspberry PI 4+

I’m having issues with nDAX TX output to the Flex. At times, it works and I see output in the P/CW level window, just as shown in the windows screenshot. I do see output from the playback audio, I think wsjtx is outputting audio, and PulseAudio is processing it, but the Flex is not seeing it. 

I would appreciate any help.

Thanks in advance,

Nick Cloyes – N4CL

PS – I send my compliments to arodland for these fine, stable apps. I’ve had lots of fun using them!

Below is the nDAX startup along with screenshots of wsjtx running in windows and Raspberry PI.

cloyesjn@ubuntu-desktop:~/sambashare$ ./nDAX

9:08PM INF Waiting for station station=Flex

9:08PM WRN Couldn't get realtime error="MakeThreadRealtime: Operation not permitted" thread="udp thread"

9:08PM INF Found Client id=0x6B9D2835 uuid=63762A21-B56D-42CF-A6C4-832706ED0018

9:08PM INF Looking for slice slice_id=A

9:08PM INF Found slice slice_idx=1

9:08PM INF Enabled RX DAX stream stream_id=4000008

9:08PM INF Enabled TX DAX stream stream_id=84000000

9:08PM WRN Couldn't get realtime error="MakeThreadRealtime: Operation not permitted" thread="rx thread"

9:08PM WRN Couldn't get realtime error="MakeThreadRealtime: Operation not permitted" thread="tx thread"

------------------------------------------------------------------------------------------------------------------------------------------------------------

pacmd list-sinks

1 sink(s) available.

 * index: 0

       name: <auto_null>

       driver: <module-null-sink.c>

       flags: DECIBEL_VOLUME LATENCY DYNAMIC_LATENCY

       state: IDLE

       suspend cause: (none)

       priority: 1000

       volume: front-left: 65536 / 100% / 0.00 dB,  front-right: 65536 / 100% / 0.00 dB

               balance 0.00

       base volume: 65536 / 100% / 0.00 dB

       volume steps: 65537

       muted: no

       current latency: 1399.48 ms

       max request: 344 KiB

       max rewind: 344 KiB

       monitor source: 0

       sample spec: s16le 2ch 44100Hz

       channel map: front-left,front-right

                    Stereo

       used by: 0

       linked by: 0

       configured latency: 2000.00 ms; range is 0.50 .. 2000.00 ms

       module: 2

       properties:

               device.description = "Dummy Output"

               device.class = "abstract"

               device.icon_name = "audio-card"

pacmd list-sink-inputs

1 sink input(s) available.

   index: 1

       driver: <protocol-native.c>

       flags:

       state: RUNNING

       sink: 1 <flexdax.tx>

       volume: mono: 65536 / 100% / 0.00 dB

               balance 0.00

       muted: no

       current latency: 200.00 ms

       requested latency: 21.33 ms

       sample spec: s16le 1ch 48000Hz

       channel map: mono

                    Mono

       resample method: copy

       module: 3

       client: 3 <QtPulseAudio:777320>

       properties:

               media.role = "production"

               media.name = "QtmPulseStream-777320-281472225262528"

               application.name = "QtPulseAudio:777320"

               native-protocol.peer = "UNIX socket client"

               native-protocol.version = "34"

               application.process.id = "777320"

               application.process.user = "cloyesjn"

               application.process.host = "ubuntu-desktop"

               application.process.binary = "wsjtx"

               application.language = "en_US.UTF-8"

               window.x11.display = ":10.0"

               application.process.machine_id = "f0bd04b5fe0d457badf0188180f8c9cb"

               application.icon_name = "wsjtx_icon"

Windows

Raspberry PI

@Nick Cloyes, N4CL another thought, since I see you're using remote desktop — make sure to disable any option in the remote desktop app for forwarding the Pi's audio to your Windows machine, as that might interfere.

All, Confirming nCAT and nDAX work with the recent Flexradio upgrade V.3.2.31. The only issue I had was with the upgrade itself - the radio got stuck and I had to remove the DC power source per instructions in the release notes.

1) From Page 4 of the Release Notes for V.3.2.31: "What to do if the firmware updates do not finish after 5 minutes?

 On rare occasions, an update may not signal the completion of a firmware update. If five (5) minutes have elapsed without the radio restarting and completing the upgrade, power off the radio by pressing the power button. The radio should restart, and the firmware update should complete normally. Note: It would be rare that a single press on the power button does not shut down the radio. However, if this occurs, remove the DC power cable from the radio to force a hard reset. Wait about 1 minute, restore DC power, wait 2 minutes and depress the power button. The radio will restart and the firmware update should complete successfully"

Hi @Mike-VA3MW , that's a weird one. The permissions don't look wrong. Were you able to figure it out? If not, I would be happy to go deeper with you.

@Mike-VA3MW alright! Sorry you ran into trouble, but glad it's behaving now.

@SmittyHalibut yup. You can also use an older nDAX (the August 17, 2020 release) which uses module-null-sink instead of module-pipe-sink, and so works with older PulseAudio... but it really doesn't work as well, there's a reason why I changed things.

You're not the first to run into this; I'll document the version requirement, and maybe see if I can have the app detect the version of PulseAudio on startup and print a message if it's too old.

@Mike-VA3MW funny, I just discovered that podcast the other day :)

I've added the version check to nDAX and I will cut a new release with the change sometime soon, which will hopefully reduce confusion.

If anyone here is feeling ambitious, it would be possible to work with older PulseAudio by implementing the read timing in nDAX and leaving out the use_system_clock_for_timing option. On paper it's not too hard — read 256 samples every 5.333ms. The question is whether it works out alright to simply use a time.Ticker to drive the loop, or whether it's necessary to do something a little bit more complicated to maintain the right long-term average in the face of apps opening and closing the device, and maybe Pulse delivering samples in chunks of its own choosing.

It doesn't help that I don't really know anything about how the Flex itself deals with the packets it gets, how sensitive it is to the timing, or how much of a buffer it may have (the only thing I do know is that it treats missing packets as silence without any real complaint).

@Ray G6UJB not currently. Would you care to file a feature request at https://github.com/kc2g-flex-tools/nDAX/issues/new?labels=enhancement ? By default it chooses a free port so that there's no chance of conflicts when running multiple copies, but I would be okay with making it overrideable.

@SmittyHalibut

No, you just want to select it for fldigi's input and output streams. It will remember the setting *for that app* (provided your PulseAudio has "module-stream-restore", which is default on every system I've run into). Setting them as system defaults wouldn't be that great, you'd probably end up transmitting a lot of beeps and stuff :)

In the new version of fldigi it's a "combo box", you can ignore the dropdown portion and type in your own value.

@Ray G6UJB Glad to help :)

Question

I am running Ubuntu on an NUC Intel based PC (x86-64). Which nDAX and nCAT file should I download?

Alan. WA9WUD