With Capsman, it would be useful i think to have an option to automatically disable Radar detection when using low power level outdoor.

Radar detection is not always reliable and can cause very long (sometimes some hours) AP detection times before interface is effectively enabled, specially when using a single or a reduced set of channels.

For short links outdoor, using low power levels, below 20 dbm EIRP, DFS and radar detection is not mandatory to stay below the ETSI regulation standard.

From ETSI :

RLAN band 2 (5470 to 5725 MHz)

Channels from 100 to 140 are part of the second RLAN band and have an EIRP power limit of 30 dBm (1000 mW) for TPC and 27 dBm (500 mW) for non-TPC devices or 20 dBm (100 mW) for devices without any TPC or DFS support. The mean EIRP power level for a slave device with TPC must not exceed 24 dBm at the the lowest TPC power level if the device is also capable of radar detection or 17 dBm otherwise. This band can be used for in- and outdoor deployments as well and is comparable to FCC U-NII-2e.

Unfortunately ros can not know what antenna is installed so there is no reliable way to presume the really radiated power. I would like to see that function legally switchable off, but it unfortunately is not so...

It would already be very helpful when DFS actually worked.
Unfortunately, when enabled the AP is constantly changing channels when mounted at a busy RF location.
It is not detecting RADAR but other RF signals. I think possibly 4G transmissions.

Router OS do know the antenna gain (dBi), there is a setting for this. And it does take this into account when adjusting the TX power level if you are using regulatory-domain mode or Capsman.

For APs with integrated antenna, antenna gain could even be hardcoded.

In the end too much regulations is painful. All this can even become funny specially when governments do allow terrible things.

Did you ever think about the noise induced by electric trains pantograph sparks ? Specially for high speed trains eating megawatts of power on the wire ?

Here is an interesting study of the power level and spectrum of radio noise generated by those sparks,

http://www.imeko.org/publications/tc4-2 ... 10-039.pdf

The conclusion is that a receiver in the train in the GSM-R band needs a minimum signal level of -70 dBm to ensure tolerable interferences


Any study about the induced noise on radar systems by those sparks ? And the level of noise induced in low frequency bands, VLF and LW radio bands ?