sidebands revisited (was: ben-wpan around the world)

Werner Almesberger werner at openmoko.org
Mon Mar 7 03:29:14 EST 2011


I wrote:
> Some of the spectra look a bit like porcupines, with spikes of up
> to -30 dB in 0.25 MHz intervals. They may be indicative of the
> build quality of the respective board, and may also indicate poor
> antenna matching.

I investigated this a little further:

http://projects.qi-hardware.com/index.php/p/ben-wpan/source/tree/master/usrp/sps/20110306/README

http://downloads.qi-hardware.com/people/werner/wpan/20110306/

Unfortunately, I reworked atusb-20110214-4 to death (*), so I couldn't
perform all the tests I had in mind, but it appears that the spikes in
atusb are caused mainly by soldering problems. Temperature also has a
small effect.

(*) Well, almost. Signal strength dropped by 10 dB for some reason.
    It'll still be suitable for software development.

- Werner




More information about the discussion mailing list


interactive