Updated 1 May 2017

CATfix: A Windows utility that controls IF Filter switching and configures the radio for digital working
by Ian Wade, G3NRW

CATfix works with both the TS-590SG and TS-590S

CATfix Options

Switching between the IF Filters when using SPLIT

CATfix monitors the radio’s TF-SET button, and (optionally) toggles between IF Filter A and IF Filter B when you press and release the button. This is especially useful when chasing a rare DX station that is working split – you can set up a narrow filter to listen on the DX station’s TX frequency and a wider filter to monitor around your own TX frequency, then automatically toggle between the two filters as you press and release TF-SET.

Setting up the radio for digital operation

CATfix provides several options that help set up the radio for digital operation. These options let CATfix automatically:
  • Turn off Auto Information, to prevent overloading the input to the application program.
  • Lock the radio’s front panel, to prevent accidental changes.
  • Set the power level (typically to a few watts).
  • Turn off the audio processor.
  • Switch both VFOs to upper sideband.

“Fixing” the “TX” command

CATfix has an option to change the “TX” (or “TX0”) CAT command issued by an application program (such as MMTTY or Ham Radio Deluxe) to “TX1”. This ensures the radio uses the TX audio that is input to the USB or ACC2 port, rather than via the mic socket.
All of these options are individually configurable in a CATfix configuration file.
Logging: CATfix lets you record all CAT commands and responses in plain-text log files, for later analysis. All
records are date/time-stamped, together with the elapsed time since the start of the session.


CATfix has three modes of operation…………..

In TF-SET Mode, CATfix monitors the radio for TF-SET button pushes. Whenever the button is pressed and released, CATfix sends commands to the radio to switch between the two IF filters.
In Interactive Mode, CATfix lets you communicate between the PC screen/keyboard and the radio. This is useful for checking out the connection to the radio, and for learning how CAT commands work.
In External Mode, CATfix intercepts CAT commands from the application program, and optionally modifies them, before passing them on to the radio.


Transceiver Support: CATfix was written specifically for the TS-590S, but most of the functions should also work with other Kenwood radios, including the TS-990S and TS-2000 (and possibly others).
Application Programs: CATfix does not require any changes to application programs, other than changing the COM port they usually use to communicate with the radio. There is no need to apply any software patches. You run application programs in exactly the same way as usual. (Also, note that CATfix operates only on CAT control commands. It has no effect on the analog TX and RX audio passing between the application program and the
No Changes to the Radio’s Firmware: CATfix does not in any way change the radio’s firmware. There is no requirement to flash a new version of the firmware.
CATfix User Guide
CATfix software and User Guide ~~~ First create a CATfix folder (for example, c:\catfix), then download the zip file into it.


Feedback from Andy Durbin, K3WYC
“As well as the features that Ian lists, CATfix is the best free serial port monitor that is compatible with 64-bit Windows 8 that I have found. It allows monitoring and recording of serial port traffic with excellent presentation of CAT traffic. It also provides a mode that allows keyboard entry of CAT commands to explore their functions and responses.
“These monitoring features make CATfix worth a look even if you don’t wish to use any of its other features.”