Re: [Discuss-gnuradio] detecting spectrum holes

[Alexander List]

John,

<rant>
may I ask you to be a bit more patient with GNU Radio beginners in 
general, and in particular with those whose mother tongue is not 
English? On top of that, the tiny hairs on my spine just got triggered, 
and that's caused by an adrenaline rush in reaction to potentially rude 
language ;)
</rant>

Back to the facts:

Google has 32.1 million hits for "spectrum hole", and about every second 
one on the first page seems to be an academic paper. So maybe some .... 
defined the term, but this won't change the fact that it's used in real 
life, even by academics. Your point reminds me of my physics teacher 
complaining that we shouldn't use the term "weight" together with 
kilograms, because kilogram is the unit of mass and weight is measured 
in Newton. You will never get rid of colloquial language entirely.

Can we please get back to a constructive discussion now and help Ahmed 
with his problem?

@Ahmed:

Problem 1: Please describe your hardware setup so that we can help:

a) What USRP model are you using? What GNUradio version, did you install 
the distribution package on Ubuntu 8.04 or upgrade to 11.10 as 
suggested? What was the exact command line you used for 
usrp_spectrum_sense.py and usrp_fft.py?
b) What daughterboard did you install inside the USRP? How did you 
connect it to the USB port of your laptop, and how to the antenna?
c) Is the USRP powering up?
d) After a power cycle (everything just switched on), does 
uhd_find_devices still give you nothing? what about lsusb -v?

In case you managed to get up to d) and have the USRP and 
daughterboard(s) detected correctly,

e) Did you connect the antenna to the appropriate RX channel of your 
daughterboard? When using WBX, there's an RX and an RX/TX port, so if 
you connect the antenna to the wrong port, you might only see noise 
except for a few *very* strong local sources. Try tuning to a local FM 
radio station... Any antenna should do for this purpose, even a 
paperclip - but don't torture the gold plated SMA connectors of the USRP 
with that :)

Problem 3 is probably caused by Problem 2. I also noticed that sometimes 
the USB stack seems to get messed up, so you might want to try a) power 
cycling your USRP and if that doesn't help, b) power cycling the laptop 
connected to the USRP.

I'm only a beginner myself, but that's what came to my mind because I 
ran into similar issues myself. If this doesn't help, please make sure 
you're at least on Ubuntu 11.10 and then we can compare results...

cheers

Alex

On 03/22/2012 11:25 AM, John Ewan wrote:
> I have had enough about this. What the heck is a spectrum hole.
> I am pretty sure this is probably a term brought up by some........
>
>
> There are NO spectrum holes. Learn about black body radiation
> and KTB........
>
> Sorry folks. the term has always erked me.
>
> We can talk about white space.....that I can take.
>
>
>
> On 3/21/12, Abdelrahman Ahmed<address@hidden>  wrote:
> > 2012/3/19 Alexander List<address@hidden>
> >
> > > **
> > > On 01/-9/-28163 03:59 AM, Abdelrahman Ahmed wrote:
> > >
> > > i'm new to this ,i need your help on how to start detecting spectrum in TV
> > > band and holes in this spectrum.
> > >
> > >
> > > Ahmed,
> > >
> > > though others will probable be able to give you more in-depth directions
> > > wrt spectrum sensing, just out of curiosity, what's your use case?
> > >
> > > Are you looking into TV white spaces? [1]
> > >
> > > Most likely you'll want to use the USRP1 with WBX because I assume it has
> > > better sensitivity than TVRX.
> > >
> > > Why would you want to transmit anything if you're just looking into
> > > analyzing spectrum usage in TV channels?
> >
> > > LP0410 is covering the right frequency band for UHF (400 MHz to 1 GHz),
> > > but it is a directional antenna. Is that what you want? Otherwise, you
> > > might be better off using an omni antenna, preferably on a roof...
> > >
> > > Here are a few pointers to papers on TV white spaces:
> > >
> > > http://www.openspectrum.eu/drupal6/node/23
> > >
> > > I've posted some of the key issues on this list two years ago:
> > >
> > > http://www.ruby-forum.com/topic/205328
> > >
> > > Dyspan has some nice papers on spectrum sensing as well:
> > >
> > > http://www.ieee-dyspan.org/2010/
> > >
> > > http://cms.comsoc.org/eprise/main/SiteGen/DYSPAN_2010/Content/Home/Technical_and_Policy_Program.html
> > >
> > > Now to the setup:
> > >
> > > *Hardware / sample data*
> > >
> > > I have a USRP1, two WBX, USRP1 N210 and an PC hardware available as well,
> > > so unless you're in a closed source / NDA environment, we could set up a
> > > code repository on github, and I could provide you with sample recordings
> > > from Hong Kong to cross-check detectors.
> > >
> > > *Regulatory environment / signals too look for*
> > >
> > > What is your location? From your signature, I assume you're in the Middle
> > > East, and I guess we're talking mostly about DVB-T signals. Is there still
> > > analog TV transmission around, wireless microphones, ...?
> > >
> > > *gnuradio packages on Ubuntu*
> > >
> > > The gnuradio packages that come with Ubuntu 10.04 are most likely a bit
> > > outdated, so you might want to upgrade your laptops to 11.10 first.
> > >
> > > 10.04 contains 3.0.4-2ubuntu1 (http://packages.ubuntu.com/hardy/gnuradio)
> > > 11.10 contains 3.2.2.dfsg-1ubuntu7 (
> > > http://packages.ubuntu.com/oneiric/gnuradio)
> > >
> > > Once you've got 11.10 with the latest packages installed, you might want
> > > to test your setup with some of the gnuradio examples, like a basic FM
> > > receiver to tune in a local radio station.
> > >
> > > Hope this helps for a start - please let us/me know on the mailing list if
> > > you need more input :)
> > >
> > > Alex
> > >
> > > [1] http://en.wikipedia.org/wiki/White_spaces_(radio)
> > hi ,
> > problem 1
> > ========
> > i pugged usrp into usb and run usrp_fft.py and i got signal like noise it's
> > amplitude -60 dB.
> > i also can run usrp_spectrum_sense.py but only numbers of frequencies
> > appeared below each other (min freq and max freq).
> >
> > problem 2
> > ========
> > when i plugged out usrp from usb and run usrp_fftw.py again  it told me
> > that can not open usrp.
> > and when i try benchmark_tx.py and benchmark_rx.py on the other lap, there
> > is an error appeared told me that
> > can not find module usrp_transmit_path
> >
> > problem 3
> > ========
> > - when i write usrp_probe i can not get any info about my usrp1.
> > - when i write uhd_find_devices it told me that:
> >
> > Could not locate USRP1 firmware
> >
> > Please install the images package
> >
> > so from these problems some programs can identify the usrp1 and the
> > other not, so what is happening here.
> >
> > Abdelrahman ahmed
> >
> > egypt,cairo
> >
> > arab academy for science and technology and maritime transport