K5KDN and KD5TFD's PowerSDR CAT Control

With Bob (K5KDN) I've added CAT (Computer Aided Tuning) control to the PowerSDR console. This allows external programs like MixW and DX Labs Commander to interface seamlessly with the SDR 1000.

Note (19 June 2005):See Bob's (K5KDN) site for more up to date details on the CAT commands being implemented in PowerSDR.

Virtual Comm Port Driver Setup

To use the CAT control with PowerSDR and a CAT control program on the same computer you will need to download and install a virtual Comm port driver. This can either be Phil Covington's (N8VB) N8VB vCOM Virtual Serial Ports Driver or the the MixW serial port emulation driver CommEmulDrv3.zip. Phil's driver is probably the better one to use, it does a better emulation of an actual comm port than the MixW driver. Once one or these drivers is installed, configure one pair of virtual comm port drivers (RTFM the appropriate docs on how to do this). You will tell PowerSDR to use one of these ports, and the external program to use the other one.

You can also use a hardware port if you want to control the radio from an external device via a serial port. In this case you do not need to use a virtual comm port driver.

PowerSDR configuration

Configuration of the CAT command parameters is done on the CAT Tab in the Setup panel. Select the CommPort you wish to use and if using the MiXW port driver also select the 'MixW Virtual Port' checkbox and and check the 'Enable CAT' check box. The code does not support flow control, so you will need to set no flow control on the external program.

Alternatively, if your external program is looking to control PTT via a comm port select PTT Bit Bang, the comm port to use and the RTS and/or DTR checkboxes as is appropriate for your program.

External Program configuration

You will need to configure the external program you wish to use to send CAT commands to the comm port pair you setup when installing the MixW virtual comm ports. This should not be the same port as the one you told PowerSDR to use. We're emulating a Kenwood TS-2000 so tell the external program that is the type of radio you're controlling

Extensions to the Kenwood CAT command set

So far we've added one extension to the CAT command set to set filter center point and width. The CAT command is:

    ZZSFccccwwww  - set filter center and width, cccc=center, wwww=width

The MixW macro below can be used to put a 100 Hz filter around a PSK signal. First cursor the desired signal and then press the button assigned to the macro. Wallah, signal is at 1000 hz, centered in a 100 hz filter:


We've not totally thought out the extension mechanism, so it is likely to change in the future.

Programs Known To Work with this

I've tested this with MixW, Commander and DigiPan (PTT Bit bang mode). NJ1H reports WinWarbler works with this setup using the MixW virtual ports. Would welcome reports of other working or non working programs.


At the moment only a limited set of the CAT commnds are implemented. VFO set/query, mode selection and filter selection are implemented.

The MixW virtual comm port code does not support timeouts so it will not work with some external programs that need timouts. Ham Radio Deluxe is one such known program. Phil Covington's driver does not have this restriction, so it you will need to use Phil's driver if you want to use a program that needs timeout support. Thanks to Phil for a virtual comm port driver that implements all of the serial port behaviors.


All of the CAT control code is integrated into the Power SDR 1.3.x line of code from Flex Radio.

Comments to: Bill Tracey (kd5tfd@ewjt.com)

Last Updated: 19 June 2005

Copyright © Bill Tracey 2005