To: WayCool, 你說“FCC就允許100mw的發射功率”，究竟你有沒有看過FCC part 15?

• Frequencies include 902-928 MHz, 2400-2483.5 and 5725-5850 MHz
• Maximum Transmitter Power Output (TPO) is 1.0 watt or 30dBm
• The formula for converting antennas from dBi to dBd is dBi-2.2=dBd

There are two different classifications for operation.
Point to Point (PTP) and Point to Multipoint (PTMP):

PTP: is when two sites talk only to eachother.
PTMP: is when multiple sites talk to a single core site.

Each of these modes have different EIRP (Effective Isotropic Radiated Power) limitations.

Point to MultiPoint (PTMP) Limitation:

• The maximum EIRP power allowed is 36dBm (4 watts).

Maximum transmitter power versus largest antenna table for PTMP
Transmitter RF power	Antenna GainM	EIRP in watts
30dBm 1W	6dBi	3.98
27dBm 500mW	9dBi	3.98
24dBm 250mW	12dBi	3.98
20dBm 100mW	15dBi	3.98
17dBm 50mW	18dBi	3.98
14dBm 25mW	21dBi	3.98
10dBm 10mW	24dBi	3.98

• Higher EIRP is allowed if the antennas are directional in nature.
• Systems operating in a point-to-point operation may use transmitting antennas with directional gain greater than 6 dBi, provided the maximum output power of the transmitter is reduced by 1dB for every 3dB that the directional gain of the antenna that exceeds 6 dBi. Maximum transmitter power versus largest antenna table for PTP:

Maximum transmitter power versus largest antenna table for PTP
Transmitter RF power	Antenna GainM	EIRP in watts
30dBm 1W	6dBi	3.98
29dBm 800mW	9dBi	6.35
28dBm 630mW	12dBi	10.14
27dBm 500mW	15dBi	15.81
26dBm 398mW	18dBi	25.23
25dBm 316mW	21dBi	40.28
24dBm 250mW	24dBi	62.79
23dBm 200mW	27dBi	100.2

This information is just provided as a guideline. We highly recommend that you read the FCC Part 15 rules and understand them before attempting any installations.

所有跟帖： 

• 瑪雅，這個是radio，不是wifi。 -WayCool- ♂ (0 bytes) () 05/07/2012 postreply 10:40:19

• 這就是wifi！不然，你找個給我看看？ -九叔- ♂ (0 bytes) () 05/07/2012 postreply 11:03:08

• WiFI不算Radio? WiFI 當然 under FCC part 15. -九叔- ♂ (0 bytes) () 05/07/2012 postreply 11:31:53

• 回複：WiFI不算Radio? WiFI 當然 under FCC part 15. -單身老貓- ♂ (290 bytes) () 05/07/2012 postreply 18:10:11

• High power WiFi AP and Adaptor -slow_quick- ♂ (707 bytes) () 05/07/2012 postreply 11:07:25

• 1000mw都有賣，你有實際測過嗎？或者打電話問問vendor看他們怎麽含糊其辭地... -WayCool- ♂ (0 bytes) () 05/07/2012 postreply 12:06:39

• 他們是怎麽含糊其辭的？ -slow_quick- ♂ (955 bytes) () 05/07/2012 postreply 13:57:10

• 找到FCC原文 -slow_quick- ♂ (453 bytes) () 05/07/2012 postreply 14:11:53

• 這很容易明白：功率放大器和天線組合起來，反映在天線端的功率應該小於4watt.(EIRP) -九叔- ♂ (353 bytes) () 05/07/2012 postreply 14:27:50

• 等效輻射功率不大於4瓦 -mc3361- ♂ (0 bytes) () 05/07/2012 postreply 14:37:05

• 0.4W怎麽變成4W? -slow_quick- ♂ (0 bytes) () 05/07/2012 postreply 14:38:09

• 天線怎麽放大功率？能量不守恒嗎？ -slow_quick- ♂ (0 bytes) () 05/07/2012 postreply 14:40:49

• FCC隻管你的天線輻射了多少功率 -mc3361- ♂ (0 bytes) () 05/07/2012 postreply 14:44:12

• 問0.1W輸出+6dBi天線=0.4W輻射。。。 -slow_quick- ♂ (0 bytes) () 05/07/2012 postreply 14:49:02

• 對功率來說，每3個分貝就是一倍，10分貝是10倍。20分貝是100倍。 -九叔- ♂ (0 bytes) () 05/07/2012 postreply 14:52:18

• 不是這麽算的 - 你要玩能量守恒必須在電源輸入端測量 -mc3361- ♂ (0 bytes) () 05/07/2012 postreply 14:52:21

• 守恒啊！因為天線隻會把能量輻射到部分空間，意思就是把能量集中在某部分，所以就增強了。 -九叔- ♂ (55 bytes) () 05/07/2012 postreply 14:50:12

• 2Gh(11a以後)wifi EIRP隻允許1w，減掉天線6db再去掉2節點損失3-6db剩下不過100多mw -WayCool- ♂ (0 bytes) () 05/07/2012 postreply 22:09:02