On Dienstag, 31. Juli 2018 10:57:03 CET Sven Eckelmann wrote: > Hi, > > I've just checked the FCC "antenna reduction workaround" patch [1] in ath9k. > The code uses twicepower (.5 dB unit used by QCA) and uses 6 (3dBi) as > allowed > gain for FCC. The comment also states "FCC allows maximum antenna gain of > 3 dBi". > > Where does the 3dBi come from? 15.247(b)(4) talks about 6 dBi [2]: > > > (4) The conducted output power limit > > specified in paragraph (b) of this section > > is based on the use of antennas > > with directional gains that do not exceed > > 6 dBi. Except as shown in paragraph > > (c) of this section, if transmitting > > antennas of directional gain greater > > than 6 dBi are used, the conducted > > output power from the intentional radiator > > shall be reduced below the stated > > values in paragraphs (b)(1), (b)(2), > > and (b)(3) of this section, as appropriate, > > by the amount in dB that the > > directional gain of the antenna exceeds > > 6 dBi. > > Btw. I am not sure whether all countries which use the FCC DFS rules also use > the same antenna gain limits. But let us assume for now that this is ok. > > Kind regards, > Sven > > > [1] > https://github.com/openwrt/openwrt/blob/81542331cb1827650f3abd69375d964d0ce2d050/package/kernel/mac80211/patches/365-ath9k-adjust-tx-power-reduction-for-US-regulatory-do.patch > [2] > https://www.gpo.gov/fdsys/pkg/CFR-2013-title47-vol1/pdf/CFR-2013-title47-vol1-sec15-247.pdf
Ping
Kind regards,
Sven
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