Jérémy,
Sorry for my delayed response to your post.
I have an LDG Z100A, AT-100ProII and an Antuner AT100M (
http://www.antuner.com/en.html), which is not related to the ATU-10 design base at all. The Antuner is closed source. I'm most impressed with the Antuner. It tunes quickly where the LDG tuners struggle and sometimes fail to tune at all, stressing a QRP rig the entire time! With its fast and accurate tuning and Li-ion battery power source, the Antuner is a perfect fit for little QRP radios.
My Antuner AT100M worked great right out of the box but, for anyone trying to weak the settings, I have a few notes that I obtained in an email conversation with the designer in China. Thank goodness for Google translate! I have no commercial interest in Antuner. My QRZ page isn't very impressive, but here are the notes:
https://www.qrz.com/db/ad8q
To play it safe, I usually tune initially using USB power on my (tr)uSDX or I flip the switch on my QRP guys SWR bridge to "tune" (limiting power and also SWR as seen by the transmitter to 2:1) and then switch the bridge to "operate" after tuning.
I purchased the SWR bridge to protect my PreppComm MMX QRP radio's very fragile finals (which blow fuses and BJTs on the board too, when the BS170s blow. It's a problem other users have experienced with the MMX too, so I reworked my PreppComm PCB and replaced the SMT BS170s with through-hole T0-92 BS170 FETs when FETs blew. Through hole parts, like the (tr)uSDX wisely uses, provide significant additional Id and power capability vs. the surface mount versions. My PreppComm experience has really made me appreciate the superiority of the (tr)uSDX! In the USA, engineers call design margin "guard band." Manuel was asking about an appropriate term for margin in on of his videos I watched. I've always liked the term.
Here's the SWR bridge:
https://qrpguys.com/tuning-indicator
I've been using it as a hook to hang my (tr)uSDX too. It seems to be able to handle the light-weight (tr)uSDX just fine! Here it is hanging on a shelf (I can never get images to display with [img]https:blah, blah[/img]
) .)
https://1drv.ms/i/s!Aj2aP2M080x7iFYct9i ... 7?e=6j2znd
Hanging it makes it easy to operate the slider switch and also see the tuning LED. I should add some sticky backed foam or rubber tape to the bottom to improve grip and protect the shelf.
73,
Cal -- AD8Q
)