About the 11g amplifier

[shellte]

A question, please help.
Is the 802.11b amplifier can be used for amplifying the 802.11g signal? Is the effect are same?

[M/Q]

I have seen 11b/g amplifiers being advertised and the same link had just 11b amplifiers also advertised. That along with the fact that they use a different method of modulation I would tend to believe that an 11b amp will not work correctly for 11g.

http://www.rflinx.com/Amplifiers/Ampliifiers.htm

[shellte]

thanks for your help.
But I still have a another question: why is the 11g amp different to 11b amp, they all work at 2.4GHz band.

[M/Q]

As I said in the first post, I am not 100% sure on this. But they have a completely different method of modulating the carrier signal and in most cases that would have to be considered in the amplification process as well. You could PM phoenix to double check me as he is very knowledgeable in that area.

[Phoenix]

Yes both 802.11b and g use the same frequency band, but 802.11g uses a much more complicated digital modulation technique to get the higher data rate. The result is that the 802.11g signal requires much tighter specifications on the power amplifier used.

[shellte]

Thanks. u r really helpful.
As i know, the AMP for 802.11b and 802.11g is almost the same in hardware design, just different in quality(a parameter may be named linearity is different, 802.11g AMP is better than 802.11b AMP in this parameter).
Do u know any website will discuess this issue?
BTW, who is phoenix. Hehe. i am a freshman of this forum.
thanks for your kindly help.

[M/Q]

Phoenix answered your post and confirmed what I had thought. Phoenix is an EE with a alot of knowledge in the wireless field. I am a an IT type for the past 35 years, as well as an amateur radio operator for 40 years. So if it is an hardware or electronic question I always value Phoenixe's opinion.

As for the difference, I would defer you to the amplifier vendor and you must be careful with amplifiers. If they are not setup correctly or are not perfoming right you will have issues that might mess up your hardware. It also might help to read some white papers about the differences in modulation between 11b and 11g. It is quite dramatic. This link will help to explain it:

http://www.tomsnetworking.com/Sections-article42-page6.php

[shellte]

Thanks for your providing information.
Actually, I am a WLAN products SSE, have been in this industry for about 3 years(a young man, right. :)).
Because so many vendor don't seperate their AMP to 11b group and 11g group( they say they are all in 2.4GHz category and no different at all) that make me confused.
I am very glad to get the correct answer from this forum. Thanks.

[M/Q]

That is why I said you have to be careful about amplifiers. The only real safe bet is to go with very well known or high quality ones. The low end ones are not much on an improvement and it is hard to actually judge the improvement. If it is not a clean amplifier either it will create spurious emmisions and get the FCC on your case.

The other important consideration is that the user is within the FCC legal output guidelines. I find many people using them and they are way over the limit.