Emergency Mode mid flight with nearly empty SD Card on 2.10.5

[lienmeat]

What I know:
I've changed very little with my TX16S other than recently upgrading firmware to the 2.10.5 recently, but this happened one time on 2.8.x too about a year ago, and I don't know why. SD card is 16gb Sandisk Edge HC 1, this one to be exact pishop.us, and only 162 MB is used, with 15.75 GB free.

I was flying FPV, and I don't know exactly what was going on on my Radio's screen at the time, and only know it went into Emergency Mode all the sudden because I lost RC link and the plane went into RTH mode (iNav saved me, thankfully) allowing me take off my goggles, see it was in Emergency Mode, and then restart the radio and recover. This happened a few minutes into my flight, and everything seemed normal to me until it happened. The other time this happened on 2.8, it also happened unexpectedly, and I never figured out why, mid-flight. I don't know where to start looking other than logs, but I don't see anything interesting there (other than it suddenly corrupts at the end).

More info (let me know if something else would help):

• MOST of the time, over the last ~2 years, this Radio with this SD card has been rock solid.
• I have the Radiomaster Ranger with the latest ELRS flashed to it (3.5.3, just flashed newest as of last night, actually, so maybe that's it?).
• I use the iNavFlight/LuaTelemetry widget when flying this plane, which was in use at the time.
• RX was HAPPYMODEL 2.4G EXPRESSLRS EP2 with ceramic antenna.

My flight log until it corrupts is attached (I removed the GPS column, the rest is intact).
flik sdb fc-2025-01-08-000545.csv

I appreciate any insight you can provide. I don't want this to happen again when I don't have RTH working right.

[lienmeat]

I think I figured this out. Short version: limit Radiomaster Ranger to 500 mw of TX Power if you see this happen, and do range tests on the ground to make sure you no longer have the issue. This does NOT appear to to be an EdgeTX issue, but a TX hardware or possibly radiomaster ranger firmware issue.

Long version.
I believe I used to be able to run my Radiomaster Ranger up to a TX Power of 1 watt & dynamic mode without issue with the TX16s, as I did plenty of flights with that as my max power setting without issues. Did some range testing, and I've found that on dynamic mode, when it decides to use > 500 mw, the radio behaves unpredictably now. Sometimes going into emergency mode, sometimes the ranger module alternates between connected and showing "no handset", sometimes the radio UI freezes but stays connected and the craft is still controllable. So far, if I make the max TX Power 500 mw, none of this ever happens on range tests on the ground.

[pfeerick]

It might be worth doing some range testing with the XT30 power input connected also, as it sounds like that the radio / circuitry / radio battery can't cope with the 1W load, making the whole system unstable. If you are using a transmitter battery with XT30 on it you can plug that directly into the module rather than it getting it's power through the handset, or use an external battery (double check you don't have a module that this applies to first! https://intofpv.com/t-psa-radiomaster-ranger-expresslrs-module-external-battery-warning)... at least that should help narrow down what is going on.

[lienmeat]

I've considered that, but I just bought a Radiomaster Boxer ELRS version so I no longer will need the Ranger for most of my flying anymore, and I wanted something smaller/more comfortable. And typically for me, 500 mw is plenty TX Power anyway, it just loves to jump up to 1 W way before it really NEEDS to. So I've really moved past this with different hardware for the most part, or just limiting output power when I do use the Ranger.