Homebrew a Serial to Kenwood CAT Interface (IF-232)

[AC0RL]

This is a simple easy to build interface for your Kenwood, I use it on my TS-790A to interface it to HRD.


kenwoodtopc.png

If your computer does not have a serial port there are several USB to serial converters.

[W9GB]

J -

Looks like the versions in 1990s ARRL handbooks (7404 for inversion of data lines).
It is different from the Kenwood OEM -- which used opto-isolaters.

[WA9SVD]

J -

Looks like the versions in 1990s ARRL handbooks (7404 for inversion of data lines).
It is different from the Kenwood OEM -- which used opto-isolaters.

The Kenwood interface used opto-isolators to eliminate ground loops associated with differentials in grounds between various pieces of equipment, such as the radio Power supply, computer, AC power line and radio.

You may or may not have success with a more simple circuit. The ARRL Handbooks showed different circuit versions for Yaesu, Icom, and Kenwood; the Kenwood versions also used opto-isolators. YMMV.

[KA9JLM]

This is a simple easy to build interface for your Kenwood, I use it on my TS-790A to interface it to HRD.

If your computer does not have a serial port there are several USB to serial converters.

It is hard to make out the drawing, do you have a bigger readable version ?


From what I can make out, it should work fine if RF and Ground loops don't get you.

[WA9SVD]

It is hard to make out the drawing, do you have a bigger readable version ?


From what I can make out, it should work fine if RF and Ground loops don't get you.

that's the whole issue with Kenwood radios. To eliminate the ground loop issue, most of the interfaces actually DO use isolated, opto-isolator coupling. (Some use isolation transformer isolation instead.) You might "get away" with a simpler interface is some situations, but that's not guaranteed. And might drive you crazy in trying to trouble shoot the problems along the way.

[N8VKX]

I question the 5 volt DC input and the Coupling Capacitors. OK on AC, not DC.

[WA9SVD]

I question the 5 volt DC input and the Coupling Capacitors. OK on AC, not DC.

I noticed that too. I would think it's an error in the drawing, and the 5 Volts goes directly to the V+ pin of the MAX232, and the capacitor is meant to be a bypass to ground.