Herelink Air Unit Firmware - Gremsy compatibility issue

Hi All,

We’ve been working on a challenging video interference issue (video link below) experienced with the Gremsy T3 and T7 gimbals. We’ve isolated and identified virtually every cause of the interference we can conceptualize and determined that the ‘source’ of the problem is the T3/T7s portion of the HDMI wiring (multiple gimbals tested). However, if we put the output of the gimbal to any other video device the video comes through clean.

The T3/T7 gimbals have an amplifier in the HDMI circuit, our best guess is that it’s increasing the noise in the signal to a point the Herelink air unit is struggling with, but a standard monitor doesn’t. We’re running air unit firmware: AAU01210729 and Herelink firmware: BRU01210730.

Has anyone seen this before or happen to know how to address it?


It’s a known issue that basically renders HDMI passthrough as useless when used with Herelink

That fact that’s it’s working even that well for you is a miracle.

I am having this same issue. I have bypassed the Gremsy HDMI straight to the air unit, however, and it seems like I have the same issue on all Sony platforms. (a6000, a6600, a7r3, a7r4)

so to take an outside view of this issue
have a read of
you will notice that 90% of the data travels from the source (camera) to the Destination (herelink),
the only 2 ways comms is DDC and CEC. on herelink CEC is not used, and DDC is used to detect the resolution etc, ie very minor traffic.

@shane we use T3 Gimbals, and HDMI from phase one camera output.

We had lots of this issue, and found that mainly the reason for this issue being the air unit and the interference on the iarunit and the Hdmi cable.

  1. we are using a shielded HDMI cable from digidirect Atomos 19.68"/50cm Straight Micro HDMI to Micro HDMI Cable | Buy at digiDirect | digiDirect

  2. Found out that out Air Unit was sitting right next to a Generator Power input, which was causing lots of interference.

  3. We were using both the HDMI input 1 and 2.

Effectively, replacing the HDMI cable with good cables, and changing the air units position away from high current emf, and also by removing the secondary HDMI input has worked flawlessly. We don’t have the glitch video anymore.

Thank you @ashwinsekar. We found a similar issue with the sensitivity to interference. We solved our issue by taking out one of our HDMI extensions and relocated the airunit to allow the user to plug directly into it’s HDMI ports for accessory video. This solved the majority of the issue and then we found that increasing the input voltage to the gimbal itself helped. We think the HDMI amplification circuitry inside the gimbal is sensitive to being near the low side of the gimbal input voltage.

Hi @shane
I am troubleshooting a similar issue with the Sony Alpha 6000, Gremsy S1, on an Aurelia X6 Pro (cube blue).
Is your HDMI running through the gimbal to the air unit? And what voltage did you increase to?

Hi @ashwinsekar
Did you ever try using the second HDMI port?


@John we bumped up the voltage to the gimbal to 15V and that seemed to help. I’d say ~80% of the issue was the extra HDMI extension we had on the airframe, and ~20% of the issue was the voltage on the gimbal power.

We did swap HDMI ports a few times on a few air units, with no affect.

Thanks @shane, found some nice HDMI and it all works perfectly now

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Glad to here @John, what specific HDMI cable did you end up going with?

@John we didnt have the need for the secondary HDMI input so never did. But will update when we do get the need to in the future.

and how a hdmi repeater works

you will notice that all the video data is one way,
the DDC is 2 way, and used to setup the image format specs.

Is there any progress with resolving this issue? I verified it is compatibility between herelink and gremsy passthrough and our machine is grounded untill we make this all work together.

Sony A7R5 → HDMI cable → Gremsy T3V3 → HDMI cable → Herelink 1.1