Gpredict and Hamlib

Configuration for the FT-991/A for FM and SSB satellites operation

CAT Configuration

"localhost" and "4532" are the default values for Hamlib. You need Hamlib to connect with the FT-991 CAT. Configuration for Hamlib is below on this page.

Bringing up the Radio Control

Click on the arrow down located on the top right corner of the Gpredict main screen

Radio Control

  1. Select the target satellite

  2. Select the transponder to use

  3. Click on Track

  4. Click on L (L for Lock, it adjust the split VFO as you adjust the main VFO)

  5. Click on Engage


Hamlib is required to control the FT-991 via CAT using Gpredict. Gpredict communicates via internal network port to Hamlib. Hamlib sends and receives data from the transceiver. Get the latest Hamlib from

Gpredict -> Hamlib -> FT-991A

I created a small batch file to run the Hamlib daemon by double clicking a shortcut on my desktop.


cd C:\Program Files (x86)\hamlib-w64-3.3\bin
rigctld -m 135 -r COM9 -s 38400 -v

Replace the COM9 with your serial port and 38400 with the speed that you have configured the CAT interface in the FT-991A