On Fri 01 Nov 2013 06:12:42 PM GMT, David Goodenough wrote: > On Wednesday 30 Oct 2013, Beat Meier wrote: >> Hello >> >> I have a lot of wireless repeaters which uses madwifi. Because of >> several problem like not anymore supported and >> other problems like "no xmit buf" I need to upgrade to mac80211 with ath5k. >> What I notice is that in the b band the ath5k driver has about 10dbm >> less than madwifi driver and a band too. >> It's not the noise it have really 10db difference. Nobody having this >> problem with long distance links? >> This is with Compex cards, CM9 ... >> Because of this I have bad througput (signal of -80) instead of -70 with >> madwifi and good througput. >> >> Any ideas what could be wrong and how to debug the issue??? >> >> Greetings >> _______________________________________________ >> ath5k-devel mailing list >> ath5k-devel@lists.ath5k.org >> https://lists.ath5k.org/mailman/listinfo/ath5k-devel > I seem to recall that there was a kludge in madwifi that added 10dB to > the real power so that high power cards could be set to their real power > limit rather than the FCC/ETSI limited power levels. Ath5k as I recall > does not do this as it is integrated into the crda data. > > Or was it the other way around, i.e. now that crda was in force with ath5k > you had to lie about the power level? > > Either way, I do seem to recall that the difference was 10dB. > > David > _______________________________________________ > ath5k-devel mailing list > ath5k-devel@lists.ath5k.org > https://lists.ath5k.org/mailman/listinfo/ath5k-devel
a) 10dB difference is too much to be a driver bug, CM9s are tested and at least the one I used to have operated as it should, I don't know which version of MadWiFi you have or how you measure the power difference. Last time I checked with a R&S spectrum analyzer tx power setting was O.K. (well at least as good as MadWiFi let's say), most probably something is going on with CRDA or some layer above the driver. b) 40MHz channels are messing up the spectrum AND in the case of the Atheros 5k cards, when used you get even less tx power. There is a 20MHz turbo mode that's better. Driver supports all possible bw modes (5,10,20,40MHz) but there is no standard way to set them. Here is a patch that enables a debugfs file to do this -> https://dev.openwrt.org/browser/trunk/package/mac80211/patches/440-ath5k_channel_bw_debugfs.patch?rev=32595 it never went upstream though, there are lots of people (and some projects out there) that successfully use bw modes. For reference here are some screenshots from an AR5413 card I used, from the R&S spectrum analyzer from 2010, when bw modes were added to ath5k. _______________________________________________ ath5k-devel mailing list ath5k-devel@lists.ath5k.org https://lists.ath5k.org/mailman/listinfo/ath5k-devel
