Noisy APT images


I’m trying to receive APT images from NOAA with a QHA antenna and I
received noisy images. I use a usrp source block, then a low pass filter
with 50 kHz of cutoff and 20 kHz of transition width, then a WBFM
and a resampler connected to the audio sink. I think that I should
the parameters of the filter.



The WFM receive block includes deemphasis processing for improving the
sound of broadcast FM reception. This is going to screw up your APT
reception. You’ll be better off making your own WFM demod block – it’s
just a quadrature demod followed by a low-pass filter.


On Thu, Mar 6, 2014 at 7:42 AM, Pablo F. Alonso <