Hi there! I have one last issue that persisted throughout yesterday's testing and I really hope you guys can point me once again in the right direction, because I really don't want to read all that is about transmitters in one night...

I own an iFLight Protek 35 HD with a premounted TBS Crossfire Nano Rx, along with a DJI Goggles v2 and a Radiomaster TX16S. The lifespan of the 4S 1550mAh battery is about 5-6 min with a GoPro (tested) and with very slow flying. For 8/10 flight, the drone kept turning of the motors at around 35m distance in open field, and the transmitter kept saying "Power signal critical". At first, I thought it was the actual battery (although I was timing it with a timer on the phone), but for the last 6 flights, I managed to connect the Custom OSD from BF to my goggles and I literally saw the radio signal drop from 99% to 50%, progressively in the next 35m. After I checked the dot in BF in the Configuration tab that said something about turning the RSSI to analog, the signal improved and the drone didn't lose signal in the exact spot it lost it in the previous flight, but the on screen RSSI was bouncing between 12-13 even though I was next to the drone.

I thought it was just a matter of fine tunning and I hoped I could do this after the shoot on Saturday, but then, the drone kept falling with a half drained battery, randomly, after 2-3 or 4 min, regardless of the signal. All the testing was done in max 60m distance radius and from my knowledge, the TBS Crossfire should waaaay more performant than that. Maybe not 40km, but at least 1km of open space. 

I just want to rely on 3min of continuous slow flight time on Saturday, not worrying my transmitter will decide to disarm the motors.

What are your thoughts on this?

P.S.: There is a Telemtry tab in my "Model" menu on the TX16S and the first thing is RSSI. The source is default and I can't change it. Then I have Low Alarm (at 35) and Critical alarm (set this up at 15 from 40 after the first random crash) and a tickbox with disable telemetry alarms (which I kinda don't want to tick, because it sounds like a bad idea).

Just to confirm, you HAVE set up the goggles to display LQ as RSSI haven't you? Actual RSSI is useless with Crossfire so you need to be using LQ. The DJI FPV Goggles don't support the native display of Crossfire LQ value but you use the RSSI "hack" to get LQ into the goggles (detailed on one of JB's videos HERE).

That said, even if you have the incorrect RSSI / LQ value displaying in the goggles, the quad still shouldn't be failsafing at just 35m. What power setting are you using on the Crossfire module and do you have it set to use the 868MHz (for an EU region) rather than 915MHz don't you?

You definitely should NOT be enabling the RSSI ADC option. That is for receivers that send RSSI over an analogue connection between the receiver and the flight controller. Crossfire receivers send RSSI via the digital CRSF data link on one of the channels.

If all of the above is fine, make sure the U.FL connector of the Crossfire antenna is properly connected to the Crossfire Nano RX. You may need to reseat it to be sure by very unplugging and re-plugging the U.FL connector being very careful not to rip the U.FL socket off the receiver. Likewise, make sure the antenna on the Crossfire module is connected properly.

To rule out or confirm the Crossfire module as a cause of the issue, are you able to test it with another Crossfire equipped quad?

The RSSI alarm on the transmitter is useless for Crossfire. Just disable it for the model and set up LQ callouts instead using Oscar's guide HERE.

Maybe it will also be worth you posting an up-to-date "dump" and "diff all" so we can look over it for any oddities with the RSSI configuration.

(06-Oct-2021, 12:07 AM)SnowLeopardFPV Wrote: Just to confirm, you HAVE set up the goggles to display LQ as RSSI haven't you? Actual RSSI is useless with Crossfire so you need to be using LQ. The DJI FPV Goggles don't support the native display of Crossfire LQ value but you use the RSSI "hack" to get LQ into the goggles (detailed on one of JB's videos HERE).

That said, even if you have the incorrect RSSI / LQ value displaying in the goggles, the quad still shouldn't be failsafing at just 35m. What power setting are you using on the Crossfire module and do you have it set to use the 868MHz (for an EU region) rather than 915MHz don't you?

You definitely should NOT be enabling the RSSI ADC option. That is for receivers that send RSSI over an analogue connection between the receiver and the flight controller. Crossfire receivers send RSSI via the digital CRSF data link on one of the channels.

If all of the above is fine, make sure the U.FL connector of the Crossfire antenna is properly connected to the Crossfire Nano RX. You may need to reseat it to be sure by very unplugging and re-plugging the U.FL connector being very careful not to rip the U.FL socket off the receiver. Likewise, make sure the antenna on the Crossfire module is connected properly.

To rule out or confirm the Crossfire module as a cause of the issue, are you able to test it with another Crossfire equipped quad?

The RSSI alarm on the transmitter is useless for Crossfire. Just disable it for the model and set up LQ callouts instead using Oscar's guide HERE.

Maybe it will also be worth you posting an up-to-date "dump" and "diff all" so we can look over it for any oddities with the RSSI configuration.

Firstly, thanks again for the quick response!

Secondly, I attached in this reply the dump and diff all after I made all the changes suggested above, after watching JB.s video as well. 

I attached to other photos of my transmitter, because I cannot change the power or the region. That was an option before I updated the firmware. Now I just have Op. Mode -Normal mode/Force Tel. under the General tab. I read in the TBS Crossfire manual that the 25mHz in power is only for the 868, so I guess that is fine... I will test out the drone as soon as I can today.

The antennas are very well attached so that is not the issue. Sadly, this is the first and only quad I have so far, so testing on other quads in not an option right now.

Thanks again and I hope everything will be okay at the test session! I will give an update as soon as I can.

Cheers!

OK, if you only have the 25mW power option and the 868MHz frequency option available then it means you have locked the Crossfire module to the EU region. That might be why you are having range issues.

You can "unlock" the module by making sure that the module is bound to a receiver (green LED on the back of the Crossfire module and a green LED on the Crossfire Nano RX), then press the button on the back of the Crossfire module 10 times in a row. Then run the Crossfire or TBS Agent Lite LUA script on your transmitter and you should then see a "Region" setting in the list. Change that to "Open" and the Crossfire module will then be unlocked again. Do not change that setting from Open to any specific region otherwise you will lock the module again. Just make sure the "Frequency" is set to "868MHz" (not "868MHz EU" or "868MHz Race"). Then set the max power to your desired level. I also recommend switching on Dynamic Power so that power will be automatically increased or decreased as needed, up to the maximum power that you have set. The higher the power the quicker it will drain the battery on your TX16S, so it is best to use the lowest power needed which is why Dynamic Power switched on is best IMO.

Note: Do not use 915MHz as it will interfere with cell phone towers (and vice versa) which will create more risk of a failsafe and could get you in trouble with telecommunications companies if they find out.

I also see that you have the "RF Profile" locked to 150Hz. Unless you have a good reason to do that, I would personally set it to Dynamic. That is how I have mine set up. Then if you get out of range for 150Hz (RF Mode 2) it will automatically switch to 50Hz (RF Mode 1) instead of just failsafing.