The popular low loss wifi coax is the LMR series. LMR100 is about 1/8"
thick and should only be used for short pigtails. LMR200 is about 1/4"
thick and looks a lot like RG-59 and is good up to 10 or 15'. LMR400 is
1/2" thick and looks like RG 213 but lower loss.
To give you an idea of the relative losses, that 30' run in LMR100 would
loose 11.7db or about 93% of the signal. In LMR200 it would loose 5 db or
about 58% and in LMR-400 it would loose 2db or about 37%.
There is an online calculator at:
http://www.timesmicrowave.com/cgi-bin/calculate.pl
One advantage of the EUB-362 is that you can run the USB cable up to 15'
(with a powered hub up to 30')with no loss and use a shorter coax to the
antenna.
Extra antenna height doesn't get you much because the absolute range over
water of a 200mw wifi signal on a 9db omni antenna is about 2 miles. With
the antenna at 10' the horizon is twice that far. Anything much higher than
the Bimini frame makes no real improvement. In some cases it could actually
work against you. Many marinas use sectorized antennas with narrow vertical
patterns and aim them down towards the end of the outer docks to get maximum
signal within the marina and minimize the spread to boats outside. If you
are anchored off the marina the antenna can be to high to be in the sweet
part of the beam.
An example in reverse is at Trellis Bay, Tortola. The BVIWifi antenna is on
the roof of the Trellis Bay Cyber Cafe. The pattern is 10 degrees vertical
and 180 horizontal and is aimed out into the anchorage. On the beach 50' in
front of the antenna a laptop will not see the signal but 30' further out on
the dinghy dock it comes in strong.
--
Glenn Ashmore
I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at:
http://www.rutuonline.com
Shameless Commercial Division:
http://www.spade-anchor-us.com
"Wayne.B" wrote in message
...
On Fri, 21 Jul 2006 04:13:05 +0000 (UTC), wrote:
Wayne, just want to be clear how you are doing this. Is the unit kept
inside and you run a cable outside with the antenna on the end? Or is
the whole unit mounted outside? If the former, any indications on
signal loss per cable length?
Is there a way to feed this into a router? Would like to be able to use
my Vonage phone service and also feed other computers in my boat.
Yes, the USB adapter is inside the main cabin feeding a 30 ft run of
low loss coax cable through an adapter (SMC to type N connector if I
recall correctly).
The antenna looks like this:
http://tinyurl.com/s6vkg
I don't know the loss figures on the cable but shorter is always
better at these frequencies. What I can tell you is that overall
system performance is a great deal better than anything else I've
tried previously. CompUSA also sells a Hawking remote
amplifier/preamp which could be installed near the antenna if mounted
in a watertight enclosure.
I don't know of any way to feed a router unless you can figure out how
to get ICS (Internet Connection Sharing) to work using a USB primary
network connection. If that is important to you, I'd recommend
looking at a remote external WiFi adapter with an ethernet interface.
The folks that I bought my USB adapter from also have a wide variety
of other components that you might find applicable:
http://www.wlanparts.com/