Archived from groups: alt.internet.wireless (
More info?)
On Mon, 30 Aug 2004 01:04:57 GMT, "DJboutit" <Recordking@Hotmail.com>
wrote:
>I am looking for better recption for my wireless network. I am looking like
>a 12 to 15 db gain outdoor antenn & a 1w to 2w signal amp where can I get
>them kinda cheap and which ones would you reccommond. If I get this setup
>and put the antenna like 30ft to 40ft high how much range would I get from
>this antenna not trying to steal internet just wondering, Right now I am
>runnin a Belkin wireless router smc wireless ethernet card & a hawking tech
>6db gain antenna about 50ft to 60ft away for router just to let you know.
Perhaps you might want to review FCC 15.247 before you purchase
something that belches too much power.
http://www.wi-fiplanet.com/tutorials/article.php/1428941
The official limit is 1 watt (+30dBm) transmit power into an 6dBi omni
antenna. If you select an antenna with more than 6dBi of gain, you
need to reduce the transmit power by the same amount. For example, a
15dBi antenna will require a power reduction of:
15dBi - 6dbi = 9dB
which translates into:
+30dBm - 9dB = +21dBm (about 130 milliwatts)
If you're building a point to point link, the rules are somewhat
different and more complex.
http://www.google.com/groups?selm=eq1qh0p31726fm0je7jldmn30qms2n312e%404ax.com
If you're buying amplfiers, I suggest:
http://www.hyperlinktech.com/web/amplifiers_2400.php
Be sure to get a power amp with automatic gain or power control or you
will find yourself with a fixed drive level.
The increase in range is difficult to estimate as I don't know what
you're comparing with the 30-40ft antenna. If you're comparing it
with an indoor installation, of course it will work better.
If you're comparing a given setup, at a given altitude, at a given
location, with a given radio, ad nausium, and only changing the power
level and the antenna gain, then the approximate rule-of-thumb is +6dB
gain in either the power amp or the antenna gain is the same as double
your range. This is in keeping with inverse square law, which
proclaims that if you double the distance, you need 4 times the power.
If you're interested in coverage area instead of range, then +3dB will
give your double your coverage area (and 1.4 times the range).
--
Jeff Liebermann jeffl@comix.santa-cruz.ca.us
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 AE6KS 831-336-2558