Yaesu FTM-400XDR - Undocumented Cross-Band Repeater Mode

I was in the market for a new dual-band amateur radio. I'm a bit of a Yaesu fan, and I was torn between trying to find a used workhorse like the  FT-8900R, or trying something a bit more modern, like the FTM-400XDR. The one thing I really wanted the '8900R for was its cross-band repeater. That was the only thing missing from the new '400XDR.

Cross-band repeater mode will listen on two different bands (usually 70cm and 2m) and repeat what's being "heard" on one of the bands, transmitting it on the other. You can use this for a variety of purposes, but it's most commonly used to boost the range of a small handheld radio when you can't feasibly take a high-powered radio with you -- such as into an office building, down in your basement storm shelter, or keeping in touch with a group of spread-out friends while in an area without good repeater coverage.

Lo and behold, the FTM-400XDR does have a cross-band repeater built-in. It's just not documented officially. It's actually pretty easy to set it up.

Start by configuring your radio's tuners the way you want them to work together. Check that the frequencies, repeater offsets, squelch are all correct, and disable APRS if you had it enabled.

In this case, I configured the top tuner to communicate with a local repeater, on medium power. It might be kind of hard to see, but there are indicators "-" and  "T-TRX" in the header of the top tuner that indicate a negative repeater offset, and "Tone Squelch on Transmit and Receive" which are common radio configurations for repeater use. You could instead set the upper tuner to a simplex frequency if you want to run it as a stand-alone temporary repeater.

The bottom tuner has to be on the other band. Since the repeater I wanted to talk through is on the 2m band, I selected a simplex frequency from within the 70cm band.  Since I plan on staying pretty close to my radio for this test, I set the power level on the bottom tuner to low power, and made sure there was no auto-repeater-shift offset. You'll notice there are no indicators in the header of the lower tuner. You would not want to accidentally link two other repeaters together. Don't cross the streams.

Power the radio off. Next, hold the SETUP, F and GM buttons under the power button at the same time. Keep holding them while you power the radio on.

When it powers up, you will see an "X-Repeater" indicator in the middle of the screen.

If you're setting up a stand-alone repeater, all users will have to configure their dual-band handheld radios for "split" operation. This varies by make and model, but you'll want them to transmit on the same frequency as the bottom tuner, and receive on the same frequency as the top tuner of the '400XDR. Anything transmitted by members of your party on the lower tuner's frequency will be repeated out to everyone else listening on the upper tuner's frequency.

To use the cross-band repeater with another repeater like I did, you'll want  to set your handheld radio to use the simplex frequency, without a repeater shift, that's displayed on the bottom tuner. The cross-band will relay bi-directionally, so whatever you transmit will be sent to the repeater configured on the upper tuner, and whatever the repeater transmits will be sent back to your handheld via the simplex frequency on the lower tuner.

To disable cross-band repeater mode, power the radio off, then use the same 3-finger-salute while powering it back on.

  • When the repeater isn't being actively used, you're still responsible for ensuring it is functioning properly. Your cross-band repeater has no way to identify itself. (e.g. CW ID) and lacks the sophistication of a real repeater.
  • You or someone you trust should be close enough to your cross-band repeater to shut it off quickly should it malfunction or otherwise transmit undesired activity (such as static, intentional interference, radio pirates).
  • Turn the radio off or disable cross-band repeater mode if you are not actively using it or are unable to monitor it.
  • Use the minimum power level possible for the communications required. This is just best-practice, but also, if you end up cross-band repeating a long-running discussion, you may overheat your radio and/or drain your car battery. Mobile radios like this are designed for a relatively low duty cycle -- transmitting only for a few minutes at a time, then given a chance to cool down while others talk. Low power (5 Watts) is probably safe for extended, continuous bidirectional operation.
  • The FTM-400XDR is capable of operating on Yaesu System Fusion (C4FM) digital modes, but under cross-band repeater mode, it will only operate in analog FM mode. You cannot cross-band repeat to a digital repeater from an analog handheld radio.
    • I do wonder if another Fusion radio could communicate through a cross-band repeater to a Fusion Repeater and vice/versa... I don't have a second Fusion radio to test this with.