On Feb 25, 6:50 am, RR wrote:
Does anyone got any experience as to which
will be the best wi-fi booster antenna to a lap-top
on board a boat?

Are you planning on using it while in the marina or do you want to
have access while at sea? Do you have authorized use of an Access
Point (AP) or are you planning on "war-sailing"? In the marina a
simple YAGI or parabolic reflector (improvement on your 1/4 wave whip
with corner reflector) would suffice. See http://www.air802.com/home.php?cat=371
for some simple antennas or http://www.wifi-link.com/ for some more
developed antennas to get dB gains over your laptop unit (these assume
you have a coax antenna connection). You can always manufacture one if
you want to experiment at low cost. Check out http://martybugs.net/wireless/biquad/
for one type of home brew, there're also ones using potato chip cans
and old TV parabolic dishes (don't laugh, they work).
Mounting the antenna on the mast won't gain you much as the AP
signal stregnth usually isn't enough for horizon path concerns and
you'll have other issues with cable legnth and clutter. You do need a
fairly clear line of sight to the AP though.
If you're planning on being at sea and accessing the internet then
the Sprint-Linksys cell system will have to suffice although you may
find cell towers don't generally radiate much on the seaward side and
you won't find any in non-populated places.
If you want to go "war-sailing", i.e. pirating AP points, you'll
need a more powerful WIFI card that'll give you better signal stregnth
receiving and transmitting along with that better antenna. Check out
"wardriving" or look at http://madwifi.org/ or
http://forums.remote-exploit.org/showthread.php?t=613 for some insight
to this.
A good laptop PCMIA card is the Ubiquiti SRC 300mW a/b/g which has
LOTS of transmitter power else look at http://www.diswire.com/WRC5.pdf
for a 12v standalone unit that'll give you 10BaseT connectivity. (It
also works the latest 5 GHz band.)
If you want to skip all the WIFI problems just get a gyro-stabilized
satellite internet system. {;