The TS-870 is a popular radio for amateur radio operators, and if you want to interface it with software such as Log4OM, you’ll need to use a CAT (computer-aided tuning) cable. In this blog post, we’ll walk you through the steps for TS-870 CAT control using OMNI-RIG.
First, you’ll need to acquire an RS232 DB9 to USB cable with an FTDI chipset. Make sure to get a male-to-male cable, as we’ll show you how to adapt it later. You’ll also need an RS232 DB9 female-to-female gender changer.
Once you have your cables, the next step is to download and install OMNI-RIG, which is the software that will allow your radio and Log4OM to communicate. Go to dxatlas.com/omnirig/ in your browser and scroll down to the downloads section. Download and extract the folder, then run the OmniRigSetup.
Once the setup is complete, open OMNI-RIG and go to the Rig 1 tab. Select your radio from the drop-down menu and enter the appropriate settings, which can be found online or in your manual. For the TS-870, select the port in device manager, set the baud rate to 9600, and set the data bits to 8, parity to none, and stop bits to 1. Set RTS and DTR to high, and set the poll interval to 500 and the timeout to 4000. Click OK.
Next, open Log4OM and go to Settings -> Program Configuration. Under Hardware Configuration, click on CAT Interface. For the CAT Engine, select OMNI-RIG and check the box for CAT auto-start. Click save and apply.
Now, when you change the frequency on your TS-870, it will automatically update in Log4OM. You can also change frequencies in Log4OM by double-clicking on a station in the cluster.
If you have a male-to-male cable, you can still use it with your TS-870 by adding the gender changer. Simply plug one end of the cable into the radio and the other end into the gender changer. Then, plug the gender changer into the RS232 DB9 to USB cable, and plug that into your computer.
Frequently Asked Questions
What cable do I need for CAT control on the Kenwood TS-870?
You need a USB-to-RS232 serial cable based on a genuine FTDI chipset, terminating in a male DB9 connector. The TS-870 has a female DB9 ACC port, so a male-to-male serial cable plus a female-to-female DB9 gender changer also works. Avoid cheap clone chipsets — they tend to drop characters and confuse Omni-Rig.
What serial settings does the TS-870 use for CAT control?
Set the COM port to 9600 baud, 8 data bits, no parity, 1 stop bit (8N1), with both RTS and DTR set to high. In Omni-Rig, configure a polling interval of 500 ms and a 4000 ms timeout. These are the values that work reliably with Log4OM, WSJT-X, and most other host applications.
Why use Omni-Rig instead of pointing Log4OM directly at the TS-870?
Omni-Rig is a single COM-port broker. It opens the radio's serial port once and then lets every Omni-Rig-aware application — Log4OM, WSJT-X, FLDigi, mapping tools — share the same connection. Without it you have to fight over the COM port any time a second program wants to read the rig.
Why is Log4OM not following my radio's frequency?
Almost always one of three things: the wrong COM port is selected in Omni-Rig, the cable's FTDI driver is not installed, or CAT auto-start is disabled in Log4OM's CAT Interface page. Confirm the COM port in Windows Device Manager, click Test in Omni-Rig until you see frequency updates, then re-enable Omni-Rig as the CAT engine in Log4OM.
Can I QSY by clicking on a DX cluster spot once CAT is working?
Yes. Once Omni-Rig is talking to the TS-870 and Log4OM is using Omni-Rig as its CAT engine, double-clicking a spot in the cluster window changes the radio's frequency and mode automatically. The same connection updates Log4OM's logging fields whenever you turn the dial on the rig.