some technical questions on Mikrotik's RouterBOARD R52n miniPCI.

1* can the built-in low-noise pre-amplifiers in the two SIGe SE2593A20 PA/LNA chips be activated/deactivated from the ar9220 ? If so, how. (in case of very-strong signals)

2* if only one antenna is connected can this cause harm to the other PA that sees no antenna and has infinite SWR. Tried to find documentation on how antenna selection is done and even looked into ath9k driver source code but antenna selection seems not to be catered for. Unclear to me whether/how tx antenna choice can be influenced.

3* the atheros spec of the ar9220 / ar7161 chipset speaks of encrytion/decryption in hardware. But in the driver this seems disabled. When using a R52n must TKIP/CCMP be done by the general purpose CPU ?

4* is it correct that your 19 dBm power @ 54Mbps 802.11a spec only applies if two antennas are used.
It appears to be twice the spec of each amplifier.

thank you!

thanks for the answers!
Looked into ath9k as I wrote already in my question (am using Mikrotik's R52n miniPCIs on a Linux platform) and was not aware of the existance of another driver. Is it open source ?