We’re checking for noisy signals with the wi-spy software v1.2. This says that the device covers the spectrum from
Technical Specs:
* Antenna * Internal PCB Trace Antenna
* Bandwidth * 2400 to 2482 MHz
* Frequency Resolution * 1 MHz
* Amplitude Range * -97 dBm to -50.5 dBm
* Amplitude Resolution * 1.5 dBm
* Sweep Time * 120 msec
It lists 14 channels (above 11 is in parentheses).
The technical specifications from crossbow explain that there is overlap between the IEEE 802.11.4 (wi-fi) and the motes.
The motes use IEEE802.15.4, which divides the spectrum between 2400 and 2480 into channels 11-26. From wikipedia “In the 2.4 GHz band there are 16 ZigBee channels, with each channel requiring 5 MHz of bandwidth. The center frequency for each channel can be calculated as, FC = (2405 + 5 * (ch – 11)) MHz, where ch = 11, 12, …, 26.”
Ch Freq
11 2405
12 2410
13 2415
14 2420
15 2425
16 2430
17 2435
18 2440
19 2445
20 2450
21 2455
22 2460
23 2465
24 2470
25 2475
26 2480
Looks like channel 11 is noisy. Channels 20 and 21 look good.
Comment by derek — September 16, 2009 @ 5:53 pm
Just noticed from the user’s guide that the on-board F-antenna is most efficient at channel 25-26 when the battery pack is on. The S11 measurement goes from about -20 to about -5 when you move from 2.47GHz to 2.40GHz.
Comment by gthomas — May 5, 2010 @ 12:48 pm