The introduction of betaflight 4.1 added another step to setting up your quad. VTX tables put the set up of the VTX in your hands.
Betaflight are rightly trying to distance themselves from us FPV pilots using a video transmitter, cough, legally. There is a big grey area here. So if you choose to set up your VTX with illegal bands/power outputs, that is on you.
There is a huge positive here though. You can now set up a VTX however you want. You can customise the channels and bands to your liking, which could come in handy if your VTX traditionally came with blocked channels, or you just want to make sure that none of the illegal channels are loaded into your VTX. Again, grey area.
All of this also means that Smart audio will not work when you first flash 4.1.
This guide will show you how to set up your VTX, which will enable smart audio and allow you to configure the VTX through Betaflight OSD in your goggles. You can also set it up in Betaflight itself, on the specially designated VTX tab. No more guessing or having to check the CLI.
Start by connecting your quad to Betaflight, without a lipo.
Check the specs of your VTX to see if it is an IRC tramp or TBS Smart Audio device. (Try the manual or the product page if you’re unsure).
This guide assumes you have smart audio wired up to a TX pad.
Step 1: Ports tab – enable IRC tramp or TBS Smart audio on the corresponding UART. (If you wired Smart audio to TX3 on your FC, enable UART 3 in Betaflight). Save and reboot.
Step 2: Blackbox tab – in the third drop down menu, select the ‘Smartaudio’ option (there will be a lot of options). Save.
Step 3: Sensors tab – deselect the gyro and accelerometer. Select the ‘debug’ option.
Plug in a lipo and watch the value in the top sensor graph.
Refer to this key to determine which type of VTX you have.
Smart Audio Debug key:
100 = SA 1.0
116 = SA 1.0 unlocked
200 = SA 2.0
216 = SA 2.0 unlocked
300 = SA 2.1
316 = SA 2.1 unlocked
Step 4: Now go here (https://github.com/betaflight/betaflight/wiki/VTX-tables).
Download the firmware according to what number you got in step 3. Right click on the name of the smart audio version, listed under the ‘File’ column. Click ‘Save link as’ and save it to your desktop. For example, my Rush VTX is TBS smart audio 2.0 – so i need to right click on Smart Audio 2.0 USA and select ‘Save to file’.
This should be a .json file. The only difference between the EU and US versions are the power options and available channels. I would use the US version.
Step 5: VTX tab – connect back up to betaflight without a lipo. In the VTX tab, click ‘Load from file’ and select the .json you downloaded in Step 4. You should see VTX bands, channels and power options now. Click Save.
Step 6: Find the manual for your VTX and double check all the bands and channels match with the newly loaded VTX table. Pay close attention to the power options as well. Smart audio 2.1 devices require an actual DB value for each power level. 25mw is 14db, 50 is 23db etc.
For all other smart audio devices 0 is the lowest power output, so 25mw.
Smart audio 2.0 – 4 power levels.
0 – 25mw, 1 – 50mw, 2 – 100mw, 3 – 600mw.
Smart audio 2.1 – 3 power levels.
14db – 25mw, 23db – 200mw, 27dbm 500mw.
(This of course can be set up to have pitmode as the lowest also, but we will leave that in this tutorial).
You can add or remove power options as you see fit. You can also do the same with bands.
Step 7: Once you are happy with the setup, click ‘Save to file’ and save this amended VTX table set up as a new .json. Put this somewhere easy to find and you can just use this next time you flash betaflight, or set up another quad with the same VTX.
You should be all done! Power up your quad as per normal, without props on of course. Go into your betaflight OSD in your goggles. Select features and then either SA or TR, depending on your VTX (SA = Smart Audio VTX’s – TR = Tramp VTX’s). Make sure that when you change the band or channel that your VTX actually swaps over. This will be obvious, because you will instantly get static. Auto search to find the new channel.
If things aren’t working for you, come on to the discord and we will be happy to help.