NANDBlaster uses a fixed transmit speed (modulation). If the signal budget for a laptop isn't sufficient to support that speed, it will fail to receive many packets.
When using normal WiFi, the transmit speed (modulation) is decreased until reliable communication can be obtained --- therefore a laptop with decreased signal budget (e.g. bad antenna) may still work, although with degraded performance. Regards, John On Jul 9, 2012, at 11:10 PM, James Cameron wrote: > That the antenna change did not work shows the problem is in the > wireless card. > > You asked why not use the same mechanism as Sugar? > > Consider the transmitter performance. > > Your network used by Sugar probably has an access point with higher > transmit power and better antenna than the laptop being used as > NANDblaster sender. > > So it is perhaps the combination of small damage to one laptop and > large damage to another laptop, that causes NANDblaster to fail. But > the combination of good access point and large damage causes Sugar > networking to be successful. > > See http://wiki.laptop.org/go/Antenna_testing#Link_Budget for a > calculation of wireless success, to see what variables are important. > > Does Sugar in ad-hoc wireless mode work between the two laptops? Or > Sugar in mesh wireless mode with no other laptops nearby? > > If so, that's very interesting. > > Open Firmware and Linux use different commands sent to the wireless card. > > I've checked, and we are using the same wireless firmware 5.110.22.p23 > in both Open Firmware and Linux (build 883). > > Daniel, do you know of any commands that the Linux kernel may have > sent to the card that may improve signal, even by accident? > > On Mon, Jul 09, 2012 at 04:06:16PM +0545, Roshan Karki wrote: >> I tried with antenna change but as you told, didn't work. So I think this is >> the dead end. Thank you for your help. But one question I wonder is in Sugar >> I >> can use very poor network very well. Why not use the same mechanism in OFW as >> well? >> >> On Fri, Jul 6, 2012 at 10:41 AM, James Cameron <[email protected]> wrote: >> >> G'day, >> >> Thanks for the photographs. There's nothing wrong that I can see >> either. >> >> Repair may attempt antenna change, but it is unlikely to be fixed with >> only antenna change. >> >> Perhaps the radio module has been damaged. On XO-1 the module is >> soldered down and is impractical to replace. In later models (XO-1.5, >> XO-1.75) the module is in a socket. >> >> -- >> James Cameron >> http://quozl.linux.org.au/ >> >> > > -- > James Cameron > http://quozl.linux.org.au/ > _______________________________________________ > Devel mailing list > [email protected] > http://lists.laptop.org/listinfo/devel _______________________________________________ Devel mailing list [email protected] http://lists.laptop.org/listinfo/devel
