Setting Up gQRX and gPredict for Automatic Doppler Correction

Today I'll show you folks how to set up gQRX and gPredict for automatic doppler correction. I'm going to assume you already have your RTL-SDR dongle working properly with gQRX and that you have some basic knowledge of gPredict. To start, make sure gQRX and gPredict are both open and running.

First, we have to add a new radio interface. To do this click Edit > Preferences. Next, on the left hand of the window click on "Interfaces". In the bottom left corner, click "Add New". The radio configuration window will pop up and under "Name" type in "GQRX", for host leave as "localhost", for port number enter "7356", for "Radio Type" select "RX only", and the rest just leave as default and click "OK". You will see GQRX added in the radio list so then just click "OK" and that brings us back to the main screen.

Next we'll bring up the radio interface. To do this we'll click on the down arrow in the upper left corner of the map display (Shown Below)

Then click "Radio Control" and this will bring up the radio interface. Since we're only receiving, we only have to worry about the downlink frequency settings. Under downlink, we'll enter the frequency of the satellite you want to listen to. I'll use Fox-1B as an example. Use the up and down arrows above and below the digits to select your frequency. For Fox-1B it would be "145.960.000".

Now go over to the gQRX window and click on the icon of two computers (Shown Below).

This will connect gQRX to the gPredict radio control. Now back on the radio control window in gPredict, select your target satellite in the pull down menu on the bottom left quadrant of the window and click on "Track" (Shown Below).

Next look at the lower right quadrant of the radio control window and make sure "GQRX" is selected in the "Device" pull down menu and then click on "Engage" (Shown Below).

Now you will see the frequencies tracking in both the radio control window and in gQRX. Next just hit play in gQRX and you'll be all set to receive your target satellite.

For some final notes, I'll list the recommended filter widths for some common satellite uses:

Fox-1B/Fox-1D: 6,000Khz - 8,000Khz (NFM Mode)
NOAA APT Satellites: 34,000Khz (WFM Mode)
Meteor M2: 110,000Khz (WFM Mode)

I hope everyone had success with this tutorial and, as always, message me or comment for corrections, input, or questions. Happy hunting ladies and gentlemen!