Re: [Discuss-gnuradio] help with "safe" and "clean" band

[Steven Clark]

On Thu, Jun 12, 2008 at 12:24 PM, Mihail L. Sichitiu <address@hidden> wrote:
>
> Hi there,
>
> I'm brand new at this GNU Radio thing, so please forgive me if my question
> has a "well-known" answer. I'd like to try out some performance tests on a
> few modulation schemes, so I need a clean band for these tests. Obviously
> the 2.4GHz ISM band is full of interference, and I assume that this goes
> for all the other ISM bands, right?
>
> If this is the case, is there a well-known relatively quiet band where I
> can run these tests without interfering with anything important, without
> being interfered with, and without getting in trouble with FCC?
>
> I imagine that if I'd have all the daughter boards I could do a long-term
> (1-2 days) scan and find a quiet band and play in there (the tests are
> likely short and low powered). The problem is that I only have the 2.4GHz
> daughter-boards and I'd like to buy only the "right" daughter-boards (as
> opposed to all of them to find an empty band).
>
> Thanks for the help,
> Mihai
>

Welcome to GNURadio. I'm not sure which bands will be noisy for you, a
lot depends on your location and what's around you. The best thing to
do is use a spectrum analyzer, if you have access to one, and see
what's out there. If you don't have one, you can fake it by using
usrp_fft.py and scanning around in frequency, looking for interferers,
etc. How "clean" is "clean"? If your signal is strong enough, your SNR
should be plenty high to run your tests. If you truly need a very
quiet environment, you may need access to special facilities, such as
an anechoic chamber.

HTH
-Steven