On Thursday 03 April 2008 08:19:07 Luis R. Rodriguez wrote: > > > Jean, if range->max_qual.level is set to -110 does this mean signal > > > level can be set only from -110 up to 0 ? Is max_qual.level supposed > > > to be the weakest signal possibly detected? > > > > Yes. This is what make most sense. > > How so? I think I must still be seriously misunderstanding something > then. If the weakest signal possibly detected is -110 dbm it does not > imply the strongest signal will be 0 dbm. On the contrary, I expect to > be able to receive frames with positive dbm values. For example, if I > hook up a card's antenna which is transmitting at 20dbm to another > card's antenna directly with cables with 10 dbm attenuator in the > middle I expect to see 10 dbm on the reception side. Therefore > shouldn't the max be close the max allowed, or at least expected, > EIRP? from a paper, from Joshua Bardwell, also available at: http://madwifi.org/attachment/wiki/UserDocs/RSSI/you_believe_D100201.pdf "Bear in mind that, realistically, stations will nearly always receive signals below 1 mW, unless they are very close (within a few feet) of the access point. Therefore, the power levels below 1 mW are critical to the operation of an 802.11 chipset." ... "Realistically, 1 mW is about the maximum power that a station is likely to receive, and the station would have to be within inches of a powerful AP to receive even that much! (That might surprise you, but remember that 802.11 NICs can receive signals down to about 10-7 to 10-9 mW, so a “weak” 1 mW signal is actually millions of times stronger than the weakest signal the card could discern.)" ... "Consequently, the RSSI ranges used by the 802.11 chipset manufacturers don’t measure at all above 1 mW. The maximum RSSI value for all 802.11 chipsets and NICs represents a power level that is less than 1 mW. Everything between 1 mW and 100 mW is simply considered “100 %” RSSI." bruno -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
