"Spacey Spade" <spaceygum@hotpop.com> hath wroth:

>[snip]
>> Anyway, depending on the answer I am now down to looking for a wireless
>> client bridge that can handle multiple MAC addresses or a single MAC
>> address and have the following requirements:
>>
>> - 802.11b/g, and hopefully also 802.11a
>> - external antenna connector
>
>If that wasn't complicated enough, I've added:

Careful. You may get what you ask for.

>- decent internal processor, flash and, um... non-flash memory

Sorry. I only deal in indecent processors. However, they do have
proper descendents.

Could you be a bit more specific as to what you consider "decent".

>- effective isotropic radiated power that is close to the legal 100mW

Please watch the terms. Isotropic means equal radiation in all
directions. I don't think that's what you want. Methinks you might
mean EIRP (effective incident radiated power) which is the xmit power
times the antenna gain. In the US, the FCC limit for point to
multipoint is 1 watt output (+30dBm) for the transmitter, and a
maximum of 6dBi (4 times) antenna gain. There are very few radios
that transmit at this high level. It's usually done with an expensive
power amplifier. It's also not a great idea as the high power xmitter
tends to cover a much larger area than it can receive, and therefore
is no better than a wide area jammer.

Are you in the US or somewhere else where the xmitter limits are
lower? RDNS shows you're in Alabama USofA.

>For example, I saw a list at a certain retailer, which showed
>"transmitted power" dbm number for only 1/3 of their 70+ models of
>access points.

You can get xmitter power specifications from the FCC type
certification reports.
http://www.fcc.gov/oet/fccid/

>I'm not sure what transmitted power means, but none of
>the models went over 20dbm, which is the legal limit (=100mW). Some
>had only 12dbm, which is awful (=16mW). You could put a high gain
>antenna on the cheapie 12dbm model, and come out the same as a 20dbm
>model.

Yeah, something like that.

Rule de thumb:
6dBi increase equals 2x the range.
12dBi increase equals 4x the range.
4 times the power equals 2x the range.
16 times the power equals 4x the range.

- Increasing the TX power does nothing for the range unless the
other end of the link also increases the power by the same amount.
- Antenna gain increases range in both directions.
- TX power increases range only in one direction.

>A little knowlege is a dangerous thing.

Too much knowledge is also dangerous. That's where I have to explain
things to those with too little.

--
Jeff Liebermann jeffl@comix.santa-cruz.ca.us
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558