Good signals from NOAA 19 with 40-10m fan dipole, but…

It was a pass of NOAA 19 with 46 degrees maximum elevation in my region. I had followed the guide on RTL-SDR website by N7FNV and KJ6IX, in setting up the station, except that instead of Orbitron, I used Gpredict to track the satellite. Tracking went on well and nice signal was received. May be something was wrong in the configuration of the virtual cable or WXtoImg. No image was decoded. I was using my 40-10m inverted V fan dipole antenna with apex at about 10m from the ground.