Digirig with FT-857D and mAT-30 auto tuner

I just acquired a FT-857D, and am setting it up with Digirig to run FT8, Winlink (VARA), Ham Radio Deluxe etc… One issue I ran into is that I can either use my auto-tuner OR the digirig cables, but not both. Which, of course, means I can only use a fairly resonant antenna, and cuts out my G5RV mostly. Any ideas?

Some tuners have a pass-through serial port so you can connect Digirig’s cable into the tuner.
If there is no pass-through, it is still possible to homebrew a “Y-splitter”. Let me know if you decide to go this route and we can figure out the pinout.

Thanks for the reply. This tuner doesn’t have a passthrough. It’s a MAT-TUNER mAT-30. Also, in the menu settings on the FT-857D, you choose between TUNER, LINEAR, and CAT. I’m wondering if that activates and deactivates the pins depending on what you’re using. But yes, I’d be interested in trying a homebrew splitter. I’m not great with making cables and soldering but I have plenty of ham friends who are!

Sounds like a plan. You’ll need one male MiniDin8 and two female MiniDin8 connectors. Signals from male side (goes into radio) will split into two female ends (Digirig and Tuner sides).

The Digirig’s side of the splitter will only need TXD, RXD and GND connections.

The tuner side can have all the connections except for the RXD line. I’m guessing the tuner doesn’t need to talk back to the radio over the serial port and we can’t have two things trying to talk into the same line anyway. Multiple things can listen to the same line so tuner can have TXD.

Here’s the pinout:


Pin numbering can be all over the pace so it’s better to orient yourself by the location of the gap in the middle row.

Looking forward to your progress updates.

I just found some more information, FYI:


Just to let you know - as you may have seen, it is possible to pass CAT traffic through the 857’s MIC port, and create a “splitter” cable from there instead of the back MiniDin8 port. See the PDF I attached. I have ordered the parts to do this and will report back. The only thing you lose is the up/down button functionality of the hand mic.


Arthur, looking forward to your report.

Please post your requests for this splitter here. If there is enough interest, I’ll add it to the lineup.

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I would like to get a CAT splitter for Yaesu too :slight_smile: With a splitter it would be very easy to run a tuner or a PA in Digimodes.

73, Stephan

**at least a splitter that puts out the ptt part of the CAT port would be great to drive PAs :slight_smile:

Denis, my cable will arrive tomorrow and I should have proof of concept for you by tomorrow night or wednesday :slight_smile:


Thanks for the update. I’m looking forward to it.

I ordered the wrong cable :roll_eyes:

Maybe this weekend

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Have you considered using something like this?

Then you could use a rj45 to 3.5 mm plug to the digirig

Interesting thought… I suppose that could work as well - thoughts, Denis??

The typical connection is through the rear panel, but from what I heard on some transceivers the CAT is also available via the front connector. The only potential issue I see is the outputs conflict when two serial devices trying to TX over the same line. Shouldn’t be an issue if mic’s TX line is disconnected.

Of course if the device was attached to the side of the radio, the mic could be unplugged while doing digital modes. It might make the device smaller and easier to use/ make.

Yes, that is a good point. However, my goal, besides digital modes, is to enable CAT control for Ham Radio Deluxe rig control and logging as well, while doing SSB voice, and having the tuner available.

I would think that this device would work for that. You would not be keying the mic when changing bands. Your in-line coupling with a wire would provide the same situation. My 857 with the mat30 tuner mean the digirig needs cat control from something other than the minidin 8.

I thought I saw this concept before. Please check out this post:

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Like that, great input!

Great thread Denis, thank you!! I have a bunch of parts arriving saturday so I’ll have options. I am going out of town sunday for two weeks, but plan to take this project with me if I don’t git er done saturday night :slight_smile:

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