I have only just found this forum recently and have read about a few ways that have been used to increase the power levels.
I did a simple script and placed it on the RC & AC. It monitors the result of iwinfo once per second and if the power level has changed it will set it back to what I want. I have not had a problem.
You could basically do this in one line..
Code:
if [[ $(iwinfo | grep -m1 Tx-Power: | awk '{print $2}') != 27 ]]; then iw reg set US; iw dev wlan0 set txpower limit 27; fi
Put it in a while loop with a sleep 1 and you have a way to keep your tx level at 27db..
If you do not how to ftp, telnet, use vi and write shell scripts you risk preventing your drone from working.
I had a look at Magic Power and it would be the safest way to do the mod. And even though I do not use it I would definitely recommend it if you want more range. I guess if the US is already set at 27db it will not make a change to the power output. BUT.
The "magic" from what I see is not so much the power output level 27db (already set I in the US), but rather Magic power has a bit of coding to adjust the ACK packet timeout when you get out to longer distances. Effectively keeping the video smoother by having less lost packets and re-sends of the video feed data.
Not sure if Papa has done any testing but there was a patch to iw to allow setting the distance to auto (dynack) and it dynamically changed the ACK timeout. That may work better for long distance. I have not done any tests as I do not fly long distance.
I just did a 50sec video of Wifi Analyser app showing the phantom signal strength if anyone is interested. It shows at 17db, 24db and 27db then back to 17 as I manually change it. It jumps about 10dBm on the scale as each change is made.