Last Post: March 28, 2005:
If the AP is communicating with more than one client, does this come under PTMP when considering the EIRP???
Or how should I need to calculate the EIRP for this purpose???
Hi Kajenveluppillai of Singapore:
The same way as with one client. Although an access point may have many client stations associated to it, the access point only transmits one frame at a time.
Please pardon me if I have misunderstood your question. I hope this helps. Thanks. /criss
In the CWNA book they had mentioned that if we are using a OMNI antenna it will come under PTMP when calculating the EIRP.
Whether we are using omni or patch antenna if the antenna serve for more clients means we should consider it as PTMP isn't it?
If that is the case then when we are calculating the EIRP for this esign we should always consider the EIRP as 4W.
Please let me know if I'm wrong.
You ask a good question. I wish I had a copy of the applicable FCC regulation at hand.
My guess is this. The FCC is only interested in power levels and how that power is directed, in this case omnidirectional versus focused. They don't care how many 802.11 stations are involved.
Thus a 2.4 GHz omnidirectional antenna is limited to 4 Watts EIRP, even if there is only one other station in the design; and a 2.4 GHz directional antenna is limited by a sliding scale that allows very high gain antennas to have much higher EIRP, even if there are multiple other stations in the presumably narrow beam of the antenna.
Please keep in mind that these relatively high power levels are typically used outdoors and sometimes involve proprietary 2.4 GHz ISM bridge designs rather than standard 802.11 access points and client stations.
I hope this helps. Thanks. /criss
Actually our project is outdoor only. That's why I wanted to find this EIRP calculation.
Mostly we used 100mW AP and 7.5 dBi patch Antenna. That shouldn't be a problem.
Now I'm thinking of using 100mW AP connected to 100mW bi-directional amplifier and then 14 dBi patch Antenna.
This antenna will be serving atleast 40-50 stations.
I don't want to go beyong FCC rules. That's why I wanted to make sure my design should be under FCC rules and will not have any problems later.
You will need another opinion besides mine.
I am curious regarding the gain of your system, what is the gain of your "100mW" amplifier?
The Gain of the amplifier will be 15dB