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OPTIMIZING SIGNAL STRENGTH VIA CHANNEL SELECTION
Aria™ wireless transceivers use radio frequencies contained within the Industrial Scientific
and Medical (ISM) band that runs between 2.4GHz and 2.5GHz. As one of the few license-
free radio bands agreed upon in most countries, many other devices also use this band,
most notably WiFi. Aria units use the ISM band in a different manner than WiFi and the two
can coexist. However, where distances between Aria units are great and WiFi access points
are reasonably close, then interference can become an issue.
WiFi uses the IEEE802.11 standard, which divides the ISM band into 13 (sometimes 14)
channels, each of which is 22MHz wide. However, the channels overlap and so cannot all
be used simultaneously. Hence, most WiFi access points settle upon channels 1, 6 and 11 to
avoid any overlap:
1
2412
6
2437
4
3
13
2
12
14
1
11
0
10
9
8
5
6
7
5MHz
3MHz
11
2462
Aria radio channels
WiFi
2.4
GHz
2.5
GHz
2.4
GHz
2.5
GHz
2
2417
1
2412
WiFi
(IEEE802.11)
channels
Channel
Mid frequency
3
2422
4
2427
5
2432
6
2437
22MHz
7
2442
8
2447
9
2452
10
2457
11
2462
12
2467
13
2472
2.4
GHz
2.5
GHz
Aria uses the IEEE802.15.4 standard, with channels that are 3MHz in width and do not
overlap. Many Aria channels do, however, coincide with the common WiFi channels. The
notable exceptions are Aria channels 4, 9 and 14, which fall into the gaps between the most
commonly used WiFi channels:
Where interference is suspected, a radio frequency survey may provide useful indications.
If you have control over the nearest WiFi access points, it is suggested that you lock them
down to one or more of the common channels (to prevent them from roaming) and select
Aria channels that sit comfortably alongside.
Note: The Aria channel notations (0 to 14) are directly equivalent to the IEEE802.15.4 channels 11
to 25, inclusive.
