why this modem is so powerful?

Hi
Why this 802.11b radio modem (http://www.data-linc.com/fastlinc/
fastlinc810e.htm) can transfer date up to 6 miles but my 802.11b
router can only 50meters?
thanks
from Peter (cmk128@hotmail.com)

In news:88dad$463e08ad$944e306e$23546@STARBAND.NET "Dana"
<raff242@yahoo.com> wrote:

><cmk128@hotmail.com> wrote in message
> news:1178469646.936611.89100@y5g2000hsa.googlegrou ps.com...
>> Hi
>> Why this 802.11b radio modem (http://www.data-linc.com/fastlinc/
>> fastlinc810e.htm) can transfer date up to 6 miles but my 802.11b
>> router can only 50meters?
>
> Transmits more power, and has a more sensitive receiver.
> Probably uses directional antenna to get the 6 miles.

Aren't there legal restrictions on transmit power and the use of
external antennas in the US?

--
Bert Hyman St. Paul, MN bert@iphouse.com

cmk128@hotmail.com hath wroth:

> Why this 802.11b radio modem (http://www.data-linc.com/fastlinc/
>fastlinc810e.htm) can transfer date up to 6 miles but my 802.11b
>router can only 50meters?

What make and model 802.11b router do you own? Some of the older
stuff is really junk.

My guess(tm) is that it's a matter of speed. Very roughly, for every
4 times increase in speed, you lose half your range. Look at the
speed versus thruput chart in the FAQ at:
<http://wireless.wikia.com/wiki/Wi-Fi#Performance_and_Speed>
It's not perfect, but it gives you the idea. Note that the BER (bit
error rate) is assumed to be constant of all speeds and ranges
(usually at BER=10^-5 reference).

Another apples and oranges comparison are antennas. Antennas make a
HUGE difference in range. For every 6dB of antenna gain, you get
double the distance. Something like:
+6dB = 2 times as far
+8dB = 2.5 times as far
+12dB = 4 times as far
+24dB = 16 times as far

Of course, the marketing department never specifies test conditions so
there's no way to know. They mumble 54Mbits/sec and 10 miles, but
they don't bother to mention that this can't be done at the same time.
The correct specs would be 54Mbits/sec up to perhaps 10ft range, or 10
miles range at 1Mbit/sec using two 24dBi dish antennas.

Fastlinc is also apparently using 200mw (+23dBm) xmit cards, so
there's about a 6dB improvement (twice the range) due to higher xmit
power.

I think (not sure) that if you look inside the FastLinc box, you'll
find a very conventional MiniPCI or PCMCIA wireless card.

--
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

<cmk128@hotmail.com> wrote in message
news:1178469646.936611.89100@y5g2000hsa.googlegrou ps.com...
> Hi
> Why this 802.11b radio modem (http://www.data-linc.com/fastlinc/
> fastlinc810e.htm) can transfer date up to 6 miles but my 802.11b
> router can only 50meters?

Transmits more power, and has a more sensitive receiver.
Probably uses directional antenna to get the 6 miles.

> thanks
> from Peter (cmk128@hotmail.com)
>

"Bert Hyman" <bert@iphouse.com> wrote in message
news:Xns99287A2FEA9B0VeebleFetzer@216.250.184.7...
> In news:88dad$463e08ad$944e306e$23546@STARBAND.NET "Dana"
> <raff242@yahoo.com> wrote:
>
>><cmk128@hotmail.com> wrote in message
>> news:1178469646.936611.89100@y5g2000hsa.googlegrou ps.com...
>>> Hi
>>> Why this 802.11b radio modem (http://www.data-linc.com/fastlinc/
>>> fastlinc810e.htm) can transfer date up to 6 miles but my 802.11b
>>> router can only 50meters?
>>
>> Transmits more power, and has a more sensitive receiver.
>> Probably uses directional antenna to get the 6 miles.
>
> Aren't there legal restrictions on transmit power and the use of
> external antennas in the US?

Yes.
But you can still use external antennas. And the link the OP posted shows
that the external amp that could be used with the modem had a 1watt output.
That kind of power with directional antenna would have no problem going the
distance advertised.

>
> --
> Bert Hyman St. Paul, MN bert@iphouse.com