SDR's vs. Hardware Scanners/Receivers

[mancow]

I haven't tried it in quite a while. It worked but I wasn't greatly impressed. Then again to be fair it was likely because I was using a small antenna and the dongles don't seem to do that well without an outside antenna in my experience. But, I can't really complain, an SDR on a phone is a pretty radical idea.

 

[br0adband]

I haven't tried it in quite a while. It worked but I wasn't greatly impressed. Then again to be fair it was likely because I was using a small antenna and the dongles don't seem to do that well without an outside antenna in my experience. But, I can't really complain, an SDR on a phone is a pretty radical idea.

Better yet might be using the RTL TCP/IP aspects and leaving all the serious SDR hardware at home and just running an app on a device (phone, tablet, etc) that connects back and provides the remote option to control the "base" while streaming out the audio. It's somewhat unwieldy to use a phone/tablet/etc with a cable attached to make use of the RTL USB stick and then attach an antenna + cable to that too.

Even better: a phone that has all the necessary hardware already inside I suppose, just needs a nice antenna attached.

 

[cobraDIHO]

I haven't tried it in quite a while. It worked but I wasn't greatly impressed. Then again to be fair it was likely because I was using a small antenna and the dongles don't seem to do that well without an outside antenna in my experience. But, I can't really complain, an SDR on a phone is a pretty radical idea.

Just wondering, but have you tried turning AGC off and manually adjusting the gain? I was disappointed by how poorly my dongle was doing with an external antenna connected, but once I turned AGC off, I got much better results.

 

[KC1UA]

I've had to set this project aside for a few days but I'm not done by any means. Frustrated, but not done. I'm hoping to continue with it towards the end of the week as my upcoming work schedule won't allow otherwise.

That said I'm kind of "up against it" here again and truly not getting anywhere. This again is due to my nearly complete lack of knowing what to do in Linux when things go wrong. I tried installing something simple like gqrx to at least be able to communicate with the dongle on a higher level than the command line, but IT won't even work and it throws up an error too. I don't have the error in front of me right now but I'll provide it if anyone is interested.

 

[PiccoIntegra]

You and I now have the same audio problem since I reinstalled Ubuntu. I haven't figured out why I can't pipe in audio(rtl_* and GR), yet the OS playes audio just fine. Ubuntu supposedly removed all OSS support, yet I see it listed(and fails all tests!!) as a plugin in the Multimedia properties. I guess GR wants to use OSS based on the errors I'm seeing. I never had this problem with the first install, I just don't get it. I got tired of dealing with it and moved on for now..

For the time being, I'll continue to play with OP25's LSM demodulation and pump the data into another computer for use with Unitrunker. It's funny, using a $10 dongle with that tiny little whip antenna on a 12" pizza pan can recover the symbols fairly accurately. My expectations on these little usb dongles were pretty low to begin with. I'm amazed by the fact I can demodulate LSM with them.

i would love to get a USRP, but man they're expensive, totally overkill for my needs.

 

[KC1UA]

i would love to get a USRP, but man they're expensive, totally overkill for my needs.

Ironically I have a BladeRF arriving tomorrow. I chose it after a great deal of research. I was close to getting a USRP B200 but the lack of Windows support scared me. The BladeRF is known to be working with SDR-Radio, which for me is a big plus as it's what I use for my RTL dongles. On the downside, there is no out of the box coverage below 300 MHz, but they are building an HF/VHF transverter that'll extend the coverage down to 50 MHz as spec'd, but 10 MHz apparently do-able with reduced sensitivity. I ordered that as well but it'll be at least late February before it's available.

Given its capabilities though I have even more incentive to win the gnuradio battle.

The RTL dongles are truly amazing, and are without a doubt a MAJOR gamechanger. I had already been into SDR, using an RFSpace SDR-14 with the IF out of an AOR AR5000A+3 receiver, but the RTL dongles made me realize the true future of the hobby, and I ultimately decided to take a leap of faith and sell the AR5K/SDR-14 combo while it still had value. I hated to part with it, but what's coming down the pike is going to be amazing.

 

[BM82557]

...The RTL dongles are truly amazing, and are without a doubt a MAJOR gamechanger... but what's coming down the pike is going to be amazing.

My thoughts exactly. Considering what my dongles cost (quite a bit less than a tank of gas) and the cost of the software (mostly nothing) it is amazing what can be done. A big THANK YOU to the developers/maintainers of SDR#, SDR# plugins, UniTrunker, DSDPlus, VB-Audio Virtual Cable, Xwxtoimg and Orbitron.

 

[KC1UA]

My BladeRF arrived on Tuesday. VERY cool piece of gear, but I'll really enjoy it when the HF/VHF transverter arrives; they're on backorder until late February so my tuning starts at 300 MHz for now. Got it working very easily in Windows; I'm working on a tutorial with screenshots, but it was FAR simpler than I expected. USB 3.0 is a nightmare; it doesn't like the USB 3.0 chipset in my Dell XPS8700 at all so I have to run on 2.0 for now at home. Naturally my work PC which is a Dell Optiplex 9020 works superbly with it, and I can see about 30 MHz of spectrum simultaneously. Hopefully the USB issues will smooth out as it develops; I'd hate like hell to have to come to work every time I want to look at more than 10 MHz at a time....

I've set up VMWare Player on my #1 PC at home and I installed Kubuntu 13.10 in a VM. I got the bladeRF running with gqrx pretty much right away, but it does nothing for me that SDR-Radio doesn't do, and IMHO SDR-Radio is FAR superior. But now with two Linux platforms at hand I'm ready to give gnuradio another try, so I'll be back to work on that project soon, hopefully with some more success.

I'll post a link to the bladeRF Windows setup instructions when I complete them. There will be tutorials for both Windows 7 and 8.1. 8.1 is a bit different as some steps need to be taken to allow the OS to accept installations of unsigned drivers, which bladeRF has. After that it's reasonably similar.

 

[PiccoIntegra]

Well, I have finally managed to solve my GR audio problems on Ubuntu. It seems there is a missing development dependency in the pybombs build script for Ubuntu, on all versions. The missing package is libasound2-dev.

If you're installing pybombs for the first time, simply install this dependency before pybombs.
sudo apt-get install libasound2-dev

If pybombs is already installed, go ahead and install the dependency as above. Once installed, go into your pybombs directory and issure the following command:
./pybombs rb gnuradio

This will rebuild your gnuradio installation and install the alsa support needed for audio sinks.

What a major PITA that was to find..

 

[NYG]

Just ordered a B200. After debating between different options I finally said screw it and ordered what I feel is the best option for me. I almost ordered a CBX board from Ettus but I want a mobile setup.

I just hope and pray it works with my Surface Pro. These USB3 boards scare the hell out of me. But, I figure Ettus (National Instruments) is the safest option in the long run.

Fingers Crossed.....................

 

[NYG]

Just ordered a B200. After debating between different options I finally said screw it and ordered what I feel is the best option for me. I almost ordered a CBX board from Ettus but I want a mobile setup.

I just hope and pray it works with my Surface Pro. These USB3 boards scare the hell out of me. But, I figure Ettus (National Instruments) is the safest option in the long run.

Fingers Crossed.....................

Changed my mind...... again! Canceled my order and will wait it out a bit longer. The more I read about the FX3 issues in Windows the more I feel I should wait it out.

 

[NYG]

Well, I have finally managed to solve my GR audio problems on Ubuntu. It seems there is a missing development dependency in the pybombs build script for Ubuntu, on all versions. The missing package is libasound2-dev.

If you're installing pybombs for the first time, simply install this dependency before pybombs.
sudo apt-get install libasound2-dev

If pybombs is already installed, go ahead and install the dependency as above. Once installed, go into your pybombs directory and issure the following command:
./pybombs rb gnuradio

This will rebuild your gnuradio installation and install the alsa support needed for audio sinks.

What a major PITA that was to find..

This was EXCELLENT. Thank you. I have a pybombs build in a virtual machine where I had no audio. This resolved it.

 

[PiccoIntegra]

Good deal.. It's ridiculous they left out this dependency in the cmake file for Ubunu installs. I found one guy on the gnuradio mailing list that had this exact problem, he got no replies. Hopefully Google picks that post up and people can find the answser.

You could also modify the cmake script in the /pybombs/src/gnuradio/cmake directory. For Ubuntu 12.04, edit the Ubuntu-12.04.cmake file with a text editor and find SET(PACKAGE_DEPENDS_AUDIO_RUNTIME "libpulse0" "alsa-base" "libjack0")
Change that to SET(PACKAGE_DEPENDS_AUDIO_RUNTIME "libpulse0" "alsa-base" "libjack0" "libasound2-dev")

This is how I found the problem to begin with.

(just giving Google more keywords to pick up.. )

 

[KA1RBI]

It's ridiculous they left out this dependency in the cmake file for Ubunu installs.

It's possible this might not have been an omission in GNU Radio - not all GR users need audio.

It might be that OP25 should add it as a prereq in the pybombs recipe.

Might be good to have you report it as a bug to OP25 using proper channels

73

Max

 

[mtindor]

It's possible this might not have been an omission in GNU Radio - not all GR users need audio.

It might be that OP25 should add it as a prereq in the pybombs recipe.

Might be good to have you report it as a bug to OP25 using proper channels

73

Max

You are kidding, right? Sure, not all GR users need audio, but all should have it available to them. Even if I wasn't attempting to decode voice, I'd still want audio available so that i could potentially send the raw audio being scrutinized to an audio output. Ears can discern amazing things.

On another note, you are the only one [that I can find] who has described GR/OP25 being used to decode CQPSK/LSM stuff. Nowhere on the internet can I find gnuradio block examples or anything that would allow a person [who doesn't know what you know] to do the same.

Do you perhaps know of any such resources that aren't easily Google-able?

Mike

 

[KA1RBI]

You are kidding, right? Sure, not all GR users need audio, but all should have it available to them. Even if I wasn't attempting to decode voice, I'd still want audio available so that i could potentially send the raw audio being scrutinized to an audio output. Ears can discern amazing things.

Well, I'm actually not kidding. Many of these leading edge projects are working with signals whose bandwidth spans more than say, 1 Megahertz and that just aren't going to be very meaningful when demodulated using familiar narrowband methods (e.g., AM/FM/SSB).

Coming from a scanner/shortwave background I had exactly the same reaction as you did (at first) - but for those signals all you'll hear is a noise that's hard to distinguish from the radio noise floor...

On another note, you are the only one [that I can find] who has described GR/OP25 being used to decode CQPSK/LSM stuff. Nowhere on the internet can I find gnuradio block examples or anything that would allow a person [who doesn't know what you know] to do the same.

Do you perhaps know of any such resources that aren't easily Google-able?

Mike

Please join the yah00 group ('op25-dev') and take a look at the mailing list archives. Also don't be hesitant to ask questions - all of us are beginning at one point in time or another. Another good place to start is this page

SignalScopePage

OP25 currently supports P25 Phase I and LSM/CQPSK works well. It depends somewhat on your SDR hardware and antenna configuration too, of course.

Max

 

[PiccoIntegra]

It might be that OP25 should add it as a prereq in the pybombs recipe.

Well, you'd still have to rebuild gnuradio in order for the audio blocks to work. I don't think rebuilding gnuradio should be a prerequisite for OP25. I didn't see this as a OP25 issue at all. Besides, I knew you'd see it here in case you're connected to those guys at GR.

 

[KA1RBI]

Well, you'd still have to rebuild gnuradio in order for the audio blocks to work. I don't think rebuilding gnuradio should be a prerequisite for OP25.

In theory there should be no need to rebuild gnuradio - one time should be sufficient.

That is, pybombs is (or should be) smart enough to install audio first, prior to gnuradio, so that by the time gnuradio is installed the audio should already be there. This of course assumes you're installing gr-op25 in the recommended way, which does not install gnuradio as a separate step, but instead you just run

   ./pybombs install gr-op25

from a blank machine, which should install all prereqs (in the proper sequence) including gnuradio.

The above may or may not be how it "should" work. Before accusing GNU Radio of having bugs I need to figure out how it *actually* works first though. Stay tuned.....

Max

 

[PiccoIntegra]

Prior to installing the ALSA development dependency, this was the relevent output during the gr-audio install:

-- Configuring gr-audio support...
--   Dependency Boost_FOUND = TRUE
--   Dependency ENABLE_GNURADIO_RUNTIME = ON
--   Enabling gr-audio support.
--   Override with -DENABLE_GR_AUDIO=ON/OFF
-- checking for module 'alsa'
--   package 'alsa' not found
-- checking for module 'jack'
--   package 'jack' not found
-- checking for module 'portaudio'
--   package 'portaudio' not found
-- Could NOT find PORTAUDIO (missing:  PORTAUDIO_INCLUDE_DIRS PORTAUDIO_LIBRARIES) 
-- checking for module 'comedilib'
--   package 'comedilib' not found

I specifically remember looking for gr-audio in the block list, which isn't listed in the 'common' list. I saw no other way of fixing the gr-audio block without a GR rebuild. Although the directories were there(/pybombs/src/gnuradio/build/gr-audio), there were no compiled libraries present in the lib directory, obviously.

 

[mtindor]

Well, I'm actually not kidding. Many of these leading edge projects are working with signals whose bandwidth spans more than say, 1 Megahertz and that just aren't going to be very meaningful when demodulated using familiar narrowband methods (e.g., AM/FM/SSB).

Coming from a scanner/shortwave background I had exactly the same reaction as you did (at first) - but for those signals all you'll hear is a noise that's hard to distinguish from the radio noise floor...

You hit the nail on the head.. I've got a pretty narrow way of thinking about this since I'm from the scanner world. But I do understand what you mean about things being monitored that are just too wide to make any sense when trying to "listen" to them.

Please join the yah00 group ('op25-dev') and take a look at the mailing list archives. Also don't be hesitant to ask questions - all of us are beginning at one point in time or another. Another good place to start is this page

SignalScopePage

OP25 currently supports P25 Phase I and LSM/CQPSK works well. It depends somewhat on your SDR hardware and antenna configuration too, of course.

Max

Thanks, Max. I will join and browse around the archives. I dig the SignalScope link.

Mike