What TX-power values can I use?
The tx-power default setting is the maximum tx-power that the card can use and is taken from the cards eeprom. If you want to use larger tx-power values, you are able to set them, but do it at your own risk, as it will probably damage your card eventually! Usually, one should use this parameter only to reduce the tx-power.
In general tx-power controlling properties should be left at the default settings. Changing the default setting may help with some cards in some situations, but without testing, the most common result is degradation of range and throughput. Some of the problems that may occur are:
overheating of the power amplifier chip and the card which will cause lower efficiency and more data errors;
overdriving the amplifier which will cause more data errors;
excessive power usage for the card and this may overload the 3.3V power supply of the board that the card is located on resulting in voltage drop and reboot or excessive temperatures for the board.
What TX-power-mode is the best?
TX-power-mode tells the wireless card which tx-power values should be used. By default this setting is set to default.
default means that the card will use the tx-power values from the cards eeprom and will ignore the setting what is specified by the user in the tx-power field.
card-rates means that for different data rates the tx-power is calculated according the cards transmit power algorithm from the cards eeprom and as an argument it takes tx-power value specified by the user.
all-rates-fixed means that that the card will use one tx-power value for all data rates which is specified by the user in tx-power field.
Note that it is not recommended to use 'all-rates-fixed' mode as the wireless card tx-power for the higher data rates is lower and by forcing to use the fixed tx-power rates also for the higher data rates might results the same problems like in the previous question about tx-power setting. For most of the cases if you want to change the tx-power settings it is recommended to use the tx-power-mode=card-rates and it is recommended to lower and not to raise tx-power.
