Hi, Does the reported RSSI on both antennas actually match? Or is the non-main antenna RSSI crappy?
If you flip the default antenna over (btu not disable diversity) does it still behave this way? -a On 17 July 2014 23:53, <brettwri...@eaton.com> wrote: > Thanks Adrian and Wojtek, > > There is a bit called AR5K_PHY_AGCCTL_OFDM_DIV_DIS which led me to thinking > it should be possible. At least now I can give up and work around it. > > I still don't fully understand why fast diversity works for CCK (11b) rates > with the same length preamble as the OFDM rates. i.e. The radio definitely > must be "looking" at the non-default antenna for those modulations, because > it receives them fine - just not OFDM. However, there is a lot I don't > understand about this radio ;o) > > Thanks > Brett > > -----Original Message----- > From: adrian.ch...@gmail.com [mailto:adrian.ch...@gmail.com] On Behalf Of > Adrian Chadd > Sent: 17 July, 2014 6:13 PM > To: Wojciech Dubowik > Cc: ath5k-devel@lists.ath5k.org; Wright, Brett > Subject: Re: [ath5k-devel] ath5k 5GHz Receive Diversity problem > > Hi, > > Right. It takes time for the hardware to figure out the signal level on each > antenna - there's a coarse gain change and then a couple of fine gain changes > so it can calculate RSSI. If the packet has a short preamble or it picks it > up a little too late then yeah, you won't get any fast diversity. > > > -a > > > On 17 July 2014 01:01, Wojciech Dubowik <wojciech.dubo...@neratec.com> wrote: >> On 07/17/2014 03:24 AM, brettwri...@eaton.com wrote: >>> >>> Hello List, >>> >>> I am having a problem getting Rx diversity to work with both ar5213 >>> and ar5413. >>> >>> What I have found is that the fast diversity works great for >>> receiving 802.11b (i.e. CCK) modulations. >>> >>> But fast diversity for OFDM just does not seem to work (and yes >>> diversity is turned ON). >>> >>> I am using controlled conditions, i.e. cable and attenuators, and >>> find that basically on the non-default antenna there is effectively >>> 30dB attenuation. This means that to successfully receive an OFDM >>> frame on the non-default antenna the signal has to be 30dBm above the >>> noise floor! Not very useful… Basically Rx diversity for 802.11a 5GHz >>> and pure 802.11g is a no-go. >>> >>> Does anyone know if this should work – or perhaps Rx diversity for >>> OFDM is just a no-go? >>> >>> BTW – I’ve tried this with ath5k/mac80211 as well as madwifi and >>> openhal, as well as the old closed source madwifi hal. They all >>> behave the same way. >>> >>> Adrian – I see you have made some changes to FreeBSD related to this >>> – do you have any idea if this **should** work? >>> >>> Anyone else? >>> >> AFAIK at least for OFDM the packet has to be seen first on default >> antenna. Then rx diversity is switching to the other antenna during >> preamble to check for a better signal. It means that first you have to >> be on a proper antenna and be able to decode a packet (or at least >> preamble). You can receive on the other one when you pump the signal >> 30dB because it's a typical isolation for antenna RF switch on >> reference designs. In our design it's typically 50dB and then for sure >> you won't get rx diversity to work if you are on the wrong antenna. >> That's why I know ;o) >> >> Rest is handled in SW i.e. if chipset has chosen alternate antenna >> three times in a row then switch default to the other one. Could be >> also based on tx failures. >> >> Br, >> Wojtek >>> >>> Thanks >>> >>> Brett >>> >>> >>> >>> _______________________________________________ >>> ath5k-devel mailing list >>> ath5k-devel@lists.ath5k.org >>> https://lists.ath5k.org/mailman/listinfo/ath5k-devel >> >> _______________________________________________ >> ath5k-devel mailing list >> ath5k-devel@lists.ath5k.org >> https://lists.ath5k.org/mailman/listinfo/ath5k-devel _______________________________________________ ath5k-devel mailing list ath5k-devel@lists.ath5k.org https://lists.ath5k.org/mailman/listinfo/ath5k-devel
