NOAA APT Satellites

The NOAA weather satellites are some of the easiest satellites to receive. For an excellent article see RTL-SDR Tutorial: Receiving NOAA Weather Satellite Images.

The NOAA satellites and APT frequencies are:

Satellite Frequency 
NOAA 15 137.6200 MHz
NOAA 18 137.9125 MHz
NOAA 19 137.1000 MHz

 

The recommended steps are:

  1. Install WXtoImg
  2. Install a virtual audio cable (VAC), either VB-Audio or Virtual Audio Cable
    • Select this device in the console (Receive DSP pane) and
    • WXtoImg recording Options
  3. In the satellite tracking window select a NOAA satellite (see the table above),
    • Add to the satellite list
    • Define the RX frequency with the Organise option
  4. in the Passes window press Current to display the passes for the currently selected satellite

An example of a APT frequency definition is shown below, note the mode is WFM (wide FM) which must be used here, the recommended bandwidth is 40 kHz:

When applied to the console the Receive DSP pane shows the values below, make sure:

  • Mode is WFM
  • Filter with is 40 kHz
  • Squelch is Off
  • Notch filter is off

 

WXtoImg Settings

There are a few essential WXtoIng steps.

Kepler Data Update

From the File menu select Update Keplers - this loads the latest data from the sites configures in WXtoImg, this is usually celestrak.com.

Recording Options

From the Options menu select Recording Options. Here you must select the same virtual audio cable configured in the SDR Console, in this example Line 1 (Virtual Audio Cable). the name depends on the VAC program you have installed. You must select the same device in the Receive DSP pane of the console.

Recording

From the File menu select Record, select Record and auto process.

 

APT Signal and Image

When you are receiving a signal the display in the console will be similar to the image below, the mode must be Wide FM (WFM) and the filter width 40kHz:

Assuming you are piping the audio via a VAC to WXtoImg your resulting image will be something like this once the recording has finished and WXtoImg has processed the data:

Yes - it's that simple!