I want to manually modify to increase the transmit power, in my country allows 433 to increase to 27dbm
Which source file parameters do I need to modify? I am using this hardware T-Beam V1.1 w/ NEO-6M
Thanks for helping my friends! Wish you a happy life
here you go - though read the warning 
boom 
In order for me to continue drinking coffee in my life, I don’t think I will increase my power!
Just use the radio to keep your coffee warm.
Has anyone tested devices to see the overheating in real life? Spec sheets can be fairly conservative.
How hard would it be to add duty cycle tracking?
Not crazy hard but a lowish priority for two reasons:
Usually the limiting factor is good line of sight (so I haven’t been super concerned about absolutely maxing xmit power).
The other reason for duty cycle is regulatory compliance in some regions and defacto our nets are usually pretty quiet.
I’d try adding forced cooling first if I wanted to do this. A heatsink and maybe a fan would probably keep things a fair bit cooler if they’r already getting hot enough to risk overheating. (A fan isn’t going to do your battery life any favours though…)
I was thinking it could be fairly easy to beef up the passive cooling for a repeater node and the extra db transmit could make the difference for people working on the edge of range.
For some of the events, especial the racing ones, I could see duty cycling reaching 100% if you have a bunch of nodes posting updates as often as possible.
If you are keen on some true manual modification, check out the SX1268, it supports 22dbm output. Some modules are apparently pin-compatible with the SX1278 you have on your T-Beam, so in theory you could swap them out. Also EBYTE makes a 30dbm version if you want to homebrew something!
Is the duty cycle automatically changed to 1% if power is to set 20 for 433mhz?
duty cycle is currently not enforced.