View Single Post
  #101   Spotlight this post!  
Unread 17-04-2008, 22:23
NCollins's Avatar
NCollins NCollins is offline
Mechanical Engineer
AKA: The Mill
FRC #1746 (Forsyth Alliance)
Team Role: College Student
 
Join Date: Apr 2007
Rookie Year: 2005
Location: Georgia
Posts: 4
NCollins is an unknown quantity at this point
Re: NEW 2009 Control System Released

OK, after numerous calculations here is the data for 802.11 channel interference. Although it is true that only 1,6,and 11 have no crosstalk AT ALL does not mean that there are only three channels with low enough interference to work.

Cisco tested a 4 channel system using 1,4,8, and 11. In their test they found an only 1% interference overlap. With such little crossover they only found problems when using a large amount of the bandwidth at one time.

Using similar calculation I extrapolated the crosstalk with the system I described above (1,3,5,7,9,11). I found a crosstalk interference of only 5.47% outside 802.11 guidelines. Also at a distance of only 12.45 inches there is a drop in power enough to lessen the crosstalk below guidelines as well.

We also need to remember that the robots this year are only running at 19.2 Kbps. 802.11 provides up to 11000Kbps.

The guidelines for 802.11 require a 30dB drop for no interference.
Reply With Quote