Ham Radio - Linux - Decoding signals from your SDR using FLDigi and Pulse Audio

[@waynesmith6417]

You are psychic Kevin. I just got an SDR off of EBAY to play with. I don't even have software yet. I wish I had more time to play. Thanks for doing such a good job.

[@rlmillr]

Have not played with SDR yet, it's just raised a point or two on my priority list. Thanks

[@loughkb]

They're fun. And with what I have arriving tomorrow, I'm going to do one more linux/SDR vid that I think you'll like also.

[@threatmitigationresearchgr7755]

Thanks for the great video. I don't have my SDR yet, but wanted to get some practice using the software. I found an MP3 of CW online and used Pulse Audio to port the audio to Fldigi and used it to practice decoding CW. Next, I'm going to play around with decoding transmissions from WebSDR until my RTL arrives in the mail.

[@gilbreathca]

Thanks for creating this series on Linux and radio applications. I've been wanting to learn about this stuff for a while now!

[@loughkb]

Cool. More to come. Trying to fill a bit of a void.

[@djdonbentley2141]

Thank you friend . Your info for piping audio to and from sdr programs and pulse audio makes me want to continue and stick with linux for all of my sdr projects. I use the distro dragon os , I like it because almost all the sdr software is pre compiled . some softwares are really hard to find and even harder to compile , So I'm glad dragon os makes it easier and saves time .

[@n8nkqrp595]

Great video Kevin. I'd love to see more hams use Linux for their ham radio hobby and bail on the nightmare that is Windoze. Most Win based loggers will run fine under Wine, and I've tried several. Although I prefer the native Linux CQRlog - N1MM, Genlog, log4om, etc work fine with Wine. And of course, there's the native Linux TrustedQSL client for connection to the LoTW server. I run and prefer Mint Linux with Cinnamon but the beauty of Linux is that we have (free!) choices in the OS! Keep up the fun and intersting videos. Good luck and good health... 73 de N8NK/QRP

[@magnehaneberg8605]

Thanks for the video! I was actually wondering about this exact question the other day (combining SDR and digimode). You make some of the most interesting amateur radio vids on KZbin. Keep up the good work! :-)

[@NamasenITN]

Thanks for your video(s). I would suggest to use the exact same setup with a simple web browser pointing to one of the many web sdr stations, in the lack of any sdr dongle/receiver. This might encourage newcomers, who might not (yet) have any radio and antenna, to play with digital modes decoding.

[@davidm1635]

Nice Kevin, also applies to any RF Capture The Flag

[@jeff-73]

Freaking amazing video tutorial. Love the zooming windows. Good job man and thanks.

[@montanawestphotography6671]

Linux sdr. YAY! The real deal. RIP windoze.

[@watsok]

Kevin, Thanks a lot for the Linux tutorials. Have been wanting to get more up to speed with that OS but there is a lack of How To's with simple but very valuable applications that you just presented. Hope to see more. Ken K1KLW

[@tomswisher5305]

Nice! I've been trying to pipe the audio between apps in Mac and Windoze; not too tough on the Mac but Windoze (as usual) is more trouble than it's worth. This is easy, though. . . click one button and away you go. Looks like it's time to update my Linux Mint install and add pulse audio volume control to it.

[@tlogesbr]

Thank you for this video! Super helpful and very well explained!

[@Jimwill01]

Thanks again Kevin. I was not aware of pulse audio volume control. Got it installed now! :) KF5AQF

[@pincus321]

thank you for your video's they help a lot

[@loughkb]

You're very welcome!

[@edbeckerich3737]

Kevin - Your SysAdmin skill are qute good ..Thanks!! PS ~ can't believe you are unemployed! Someone should grab you!!

[@NickkoG]

Absolutely awesome, try to do something like this (use SDR to decode signal in other program) since so long. Have you tried with SSTV?

[@loughkb]

Yes it also worked fine.

[@pxykckyx]

Good, but the problem (in linux) is when you want decode digital audio like DMR because you have another audio stream over sdr out. I've tried Dsdccx with Sdr++ but not working for me, i've no audio output. I notice that with pulse a virtual sink doesn't work (in my case Mxlinux), not like "virtual cable" in windows.

[@stevejones8665]

Great Idea Thanks for the info about pulse Audio....I wonder if this could be used with asterisk and an allstar node instead of having an interface card for your audio? ....Cheers Steve M0BFM Liverpool ZL3LFC

[@vegepetteri4293]

nice no terminal audio pipe. Finally can try :D

[@MoTown44240]

Used it with QSSTV too.

[@loughkb]

Yep, it will work with any application that records through Pulse Audio. I even used it today to decode POCSAG paging transmissions from a local hospital using the CubicSDR as the source and a terminal program called multimode-ng.

[@jay-rus4437]

QUESTION? Ive successfully setup VB-Audio, Virtual Serial Port Emulator, SDRuno, and FLDigi....however I am having a very difficult time decoding. I get a lot of random letters and characters, but nothing readable. I know everything must be connected correctly because I have decoded two transmissions that were readable. And just to clarify, I am also using a Chameleon Emcomm III in an inverted L configurations Can you give me some advice on some things I might do to receive more consistently?....having same issues with JS8Call

[@napomania]

one of the useful video ever! can i decode even somthing i monitor with the external microfone or with phones out of my radio? thanks

[@loughkb]

You can simply select your computers mic input as the source in fldigi. There are also decode apps for cell phones for some modes like CW, SSTV, and others.

[@jemussi7842]

Wow, thanks for this. So much disinfo on this topic. I ended up trying to do this by installing JACK. This seemed to mess up my ubuntu and I uninstalled it but now I can only lauch apps by opening a new terminal tab for each one and I have to keep them open to keep the apps running. Any solution yo this? I'm not very good with linux.

[@Kennynva]

You think this will work on Linux mint 18?...I can see in the app, download section pulseaudio listed...I have "VlC-pluging-pulse" listed as installed now..and "pulseaudio-module-x11" installed to...Never-mind..I just seen pulseaudiocontrol listed...

[@Huanchee]

Ugh...is there any alternative to pulseaudio I could use? I’m wanting to do this for a raspberry pi4, but pulse audio always “breaks” the pi audio in raspbien. It never allows me to switch back to the analog 3.5mm jack or hdmi port for audio properly. Anytime you switch to it, it instantly forces volume control to stay at 2%, try to increase it and it instantly deselcts the analog or hdmi setting, if you try to reselect them, it resets back to 2%. There is a “fIx” I found after well over a month messing with it, but it’s a headache workaround, and honestly after my nightmare experience with pulse trying to constantly get it working properly, I just never want to deal with it again. It’s why i use cubicsdr on my pi instead of GQRX, despite me liking the simpler ui and being less taxing on the cpu with gqrx. GQRX forces you to use pulse, while cubic “just works” without any major headache on the pi, but It’s just so cpu heavy for even the pi4.

[@kg7yts187]

Can you make a video on how to do Linux FlDigi with an IC-7100?

[@loughkb]

Not reliably, I don't have a 7100. I'd just be guessing at certain things and I don't want to mislead anyone.

[@NickFarrow]

Any idea how to clear the PluseAudio Server string in FLDIGI config GUI. I kind of had space in there and now I get this popup that says Pulse Audio error when I try to check the box to even remove the space. :(

[@NickFarrow]

Go to the home directory of the user you are logged into with, then type, rm -rf '.fldigi'

[@geraldellis1177]

what about p25 and other 800 mhz comm protocols

[@mercster]

Ancient video, sorry... Linux seems to change to a different goddamn audio backend every 5 years or so; they keep saying "Oh this is the sound server of the future" but they'll switch to another one soon, and add another friggin' compatibility layer. So, I'm on recent Ubuntu which uses PipeWire... I have pavucontrol, I can find the fldigi entry in Recording tab and "Monitor of Built-in Audio Analog Stereo" is there, but it won't let me switch to it. For whatever reason, it's not even greyed out, it just refuses to be selected. Farthest I've gotten is having it listen to a microphone on my desktop, but that's probably not optimal. What a ballache. Thanks for the video anyway.

[@loughkb]

In order to use pulse audio volume control, I think you'll need to remove pipewire and install pulse audio. Or find out if there's a similar utility available for pipe wire. I have not had the opportunity to play with it yet so I can't help there, sorry.

[@RobbieStrike]

Great video, Helped me get FLDigi going and working playing around with it. Did you do a video about how to listen into amature digital modes? I got my SDR going and having fun with the new toy kzbin.info/www/bejne/jqTdaqGHeL1jiKM Do you know of a program or ad on to use a sdr like a scanner to find frequency that are being talked on?

[@LTellet]

Great video, but any chance you could do one on installing one of the SDR programs for Linux. All of them seem to need full compiling and the installation of many dependencies. I am still running 12.04 so that might be my problem (the programs you use don't seem to come up in Synaptic).

[@loughkb]

GQRX should be in synaptic. It will work with any of the RTL type dongles. You may have to blacklist a kernel module though. I think instructions were over on the RTL SDR forum. I used GQRX back when I was on ubuntu 12.04. With any newer linux, you can install SoapySDR from within synaptic and get support for many of the SDR's out there. They should work through GQRX. Another thing to try is Skywave Linux. See my video on it. It's a live CD with most of the SDR programs already installed and configured to work, including Cubic.

[@biringen]

HI i have Audio input is ok for decode,, but how do i get audio out to my interface (microham microkeyer2) have no output to radio,,,, i use cqrlog with wsjtx..mhuxd is installed and working for rigcontrol

[@loughkb]

Choose the audio device that's created by the interface. It should show up under the hardware tab in the system audio mixer.

[@biringen]

@@loughkb Fixed it, i had to sudo adduser mhuxd audio

[@montanawestphotography6671]

Will this decide Morse code? If so how?

[@loughkb]

Morse is one of the many modes FLDigi supports. Just switch it to CW mode and click on the signal in the waterfall.

[@RamLaska]

Hey +Kevin Loughin, I was wondering if it's possible to construct an antenna reflector (like a satellite dish) to focus the power from a whip into a specific direction when hitting remote repeaters or satellites (mainly SO-50).

[@BEdmonson85]

Ram Laska, Yeah, its called a yagi or some hams call 'em beams. Its fairly easy to construct one from scratch too. To give you an idea, try googling "7db for 7 bucks" its an old article describing how to construct a simple 3 element beam from parts available from most local hardware stores. I'm using a variation of that antenna that I built for use with my VHF AX.25 packet node running a BBS and RMS node. It works quite well.

[@BEdmonson85]

Ram Laska, To be a little more clear. When trying to work satellites or distant repeaters, an omni-directional antenna is not the best option. You really need something a bit more directional and with gain. You could build a colinear array or something, but I believe a simple yagi would be a less complicated and much easier solution to construct, not to mention less expensive. Oh, and for those distant repeaters, I'll tell you what my elmer told me... height is king with vhf and above. Get that antenna as high as possible! Good luck and 73!

[@stevejones8665]

Ram Laska I agree with some of the replies you have had.....forget Dishes and Dipoles LOL Just build a 3 element or more Beam Antenna also known as a Yagi and point that towards the Repeater or station you want to contact...You will be amazed how well a cheap homemade beam works....Also you could try a J pole made from copper plumbing fittings and copper pipe....Good luck Steve Liverpool

[@RamLaska]

Thanks guys. I was hoping I could just make a simple reflector plate/dish, rather than constructing a yagi, but I guess yagi is the way to go then.

[@watsok]

The problem with using a antenna like a dish / parabola is that the gain vs size is frequency dependent. @ meter dish would be several 1/4 wave lengths in diameter for any reasonable gain. Yagi's are also frequency dependent but only grow one direction vs circular and they usually have a lot less material and wind load for the gain. Not to mention a lack of surface tolerances like a parabola. Look at corner reflectors. A mid point between Yagi and parabola with reasonable gain for size and weight.

[@knightsofnee8626]

Is this used in the Skywave distro?

[@loughkb]

I'm not sure if pulseaudio volume control is included by default on skywave. But you could install it. And then you could do this.

[@geraldellis1177]

so this decodes digital audio