Hi,
Using Matek H743-SLIM V3 with stable-bshot-4.4.4
Starting from:
VTX_MAX_POWER, 400
VTX_POWER, 400
VTX_OPTIONS, 0
SERIAL5_PROTOCOL, 37
SERIAL5_OPTIONS, 68
SERIAL5_BAUD, 5
RC5_OPTION, 0
VTX_OPTIONS, 0
Things are as expected, ardupilot boots and enters 400mW VTX
If I change to:
RC5_OPTION, 94
VTX_OPTIONS, 1
Ardupilot boots into pitmode (as expected). If I flip radio switch to max (2000μs PWM), VTX_POWER flips to 1585 (max power of RUSHFPV RUSH TANK SOLO)
I’m using throttle trim to RC5, sticky. So it starts with 999μs PWM until I switch trim down, then it keeps at 2000μs (until I reboot radio or radio script). I want to keep this as a way to have something useful for RC5 (required in the radio for ELRS), and having VTX_MAX_POWER being respected.
I’m missing anything in this configuration? Any clues?
Thanks!
There are a couple of VTX bugfixes in ArduCopter 4.5.6 and ArduCopter 4.5.7 is about to be released next week.
Why don’t you update and test if the problem is already fixed?
Ardupilot versions changes so fast (and that’s a good thing!). The point is it changes faster than my capacity to test drone comprehensively (eventual new bugs or details, etc). So I was considering 4.4 a “freeze” for my drone project for some time.
Anyway so it looks like I have no problems in settings (supposed to work). That’s important to know. And yeah I see no problem trying 4.5.7 and watch what happens in regard to my VTX issue.
Thanks!
Reporting back,
Upgraded to 4.5.6 for this test and it started working as expected.
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Nice, I am glad it worked. One less bug to fix. One more satisfied user 
Restored 4.4.4 from backup.
Testing further it started working (respecting VTX_MAX_POWER) doing:
‘RC5_OPTION, 0’ and ‘VTX_OPTIONS, 15’ instead. And ‘pitomode until armed’ and ‘pitmode when disarmed’ doing as expected as well
Reverting to an older version that has known bugs that have been tested and fixed in a new stable and widely used version is unwise.
But it is your call to make.
Thanks!
Well I rolled it back because installed 4.5.6 now just for this test and will need to accomplish a drone task the next time I go to he field. I think it makes sense doing tests after upgrading, before going to missions etc. Looks like also it makes sense now to wait for 4.5.7 
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