wxapt:
wxapt is a console application for decoding and saving weather images transmitted in the APT format of NOAA and METEOR satellites. It seems that at the present time (fall 2005) there are still no satellites transmitting in the latter format in the 137 MHz band, that I know of at least. But there are a few NOAA satellites that operate continuously in this mode and frequency band: NOAA-12 and NOAA-15 are the "veterans" of the field and NOAA-17 and NOAA-18 are the current morning and afternoon pass birds.
Manual Read more details on-line or download wxapt's manual
Package Download source package of wxapt
xwxapt:
xwxapt is a GTK+ graphical version of wxapt. It uses the same decoding engine as wxapt but it displays APT images at half-size as they are received, storing the full-sized files when reception is completed. It also displays some status information (audio level, sync level, sync status etc) and text messages as it runs.
Manual Read more details on-line or download xwxapt's manual
Package Download the (last!) source package of xwxapt with a GTK+-2 GUI.
Package Download source package of xwxapt with a GTK+-3 GUI.
This is xwxapt decoding APT images as received
with a NooElec RTL-SDR dongle from NOAA-19
Xwxapt receiving NOAA-19 Ch. A+B
xwxapt
Images flipped and pseudo-colorized
xwxapt
These are APT images decoded by xwxapt as
received with a NooElec RTL-SDR dongle from NOAA-19

NOAA-19 Channel A
apt

NOAA-19 Channel B
apt

Colorized (A+B)
apt