[Hackrf-dev] foldover

[Kevin Reid]

On Aug 31, 2014, at 15:12, McDonald, J Douglas <jdmcdona at illinois.edu> wrote:

> In particular in "wraparound" of the FFTs is abysmal. It renders it
> virtually useless for SW reception. It seems to work equally
> well or badly with or without one of those 125 
> M Hz upconvertors; however I am feeding it from a fairly good
> antenna and  a very good source follower 50 Ohm out preamp
> at the antenna end of about 50 feet of coax.
> 
> Using the cheapie dongles, though they have only 2.8 MHz bandwidth,
> the foldover is pretty well down 800 kHz from the foldover pint.
> On the HackRF,  its still visible 10 MHz on the wrong side! 

Unlike the RTL-SDR devices, HackRF One has a selectable filter bandwidth -- at least, as exposed by gr-osmosdr (I haven't seen SDR#'s configuration options).

The misbehavior you describe would occur if the filter was too wide for your choice of sample rate.

-- 
Kevin Reid                                  <http://switchb.org/kpreid/>