Omega Vehicle Security zSeries manual Fine Adjustment in Performance, Channels

5.5 Fine Adjustment in Performance
1. To avoid interference from WiFi / IEEE 802.11, one could consult the figure below to
choose the best channel through the Configuration webpage. In all, channels 15, 20,
25 and 26 are not overlapping with any WiFi / IEEE 802.11 bands in the United States
while channels 15, 16, 21 and 22 can be used in Europe.
		1					Channel					11
US WLAN							6
(IEEE 802.11B)
non-overlapping
2400 MHz		2412					2437					2462					2483.5 MHz
								22 MHz
European WLAN		1						Channel						13
								7
(IEEE 802.11B)
non-overlapping
2400 MHz		2412						2442						2472			2483.5 MHz
								Channel			2 MHz
IEEE 802.15.4	11	12	13	14	15	16	17	18	19	20	21	22	23	24	25	26
2400 MHz PHY
	2405	2410	2415	2420	2425	2430	2435	2440	2445	2450	2455	2460	2465	2470	2475	2480	2483.5 MHz
2400 MHz					Figure 5.4 Channels

2. It is possible that IEEE 802.15.4 devices experience interference from Wi-Fi / IEEE 802.11 and Bluetooth devices and certain microwave ovens. Therefore, it is worth locating nodes as far as possible to minimize effect. Note that international radio regulations which govern radio equipment ensure that cell phones use their allocated band only. It is highly unlikely that cell phones will interfere with IEEE 802.15.4 equipment.

3. In some cases, a short RF cable may be used to connect an antenna to your device. Please note that RF extension cables will always add some loss to the transmitting signal strength. The longer the cable the more signal will be lost over that cable. Therefore, the length of the cable should be kept as short as possible. Also, note that use of any other antenna other then what’s shipped with your device will void FCC and CE regulatory complicance.

4. To achieve satisfactory IEEE 802.15.4 performance in the presence of WLAN

interference, a channel center-frequency offset of 7 MHz is recommended.

5. For co-channel operation, a physical separation from the WLAN Access Point (AP) of 26.2’ (8 m) is recommended to achieve a Packet Error Rate (PER) of 1%. For a particularly saturated WLAN link, 29.5’ to 32.8’ (9 to 10 m) may be necessary.

6. To achieve satisfactory IEEE 802.15.4 performance in the presence of Bluetooth interference, a separation distance of 6.5 ‘ (2 m) is recommended.

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