| What AP's can operate on 12 Volts?

The Linksys WRT54G series can. I've got a pair of them on my boat. One's
in the radar arch maintaining the link to shore. The other's down in the
cabin providing an on-boat wifi network. Works pretty well once we're at
anchor.

| Can I do this with just a AP, wired to the lan jack on my laptop?

You could do it with a wire straight from the wifi unit. But having a wired
laptop might not be terribly convenient. You'd have to deal with that cord
all the time. Run the wire from the up-mast device to the in-cabin device.

Remember when considering a high gain (especially a directional high gain)
antenna that boats rock and even if in an small inland lake you can get
considerable signal drop out if the gain is much over 3db.

True, and higher gain may also pull in a wider set of networks. You'd end
up listening to "too many" and get even worse performance. And the
radiation pattern from most of these antannae is shaped like a donut. When
the boat is rocking that donut gets tilted up and down, in and out of the
coverage area. Higher gain antennae have a much narrower area of coverage.
So any rocking with a typical 14db omni would render it almost useless.
Same deal goes for a directional antenna, if you swing on anchor there goes
the coverage.

Depending on where you're planning on travelling and how you're anchoring
there would be different recommedations. I've had a 10db omnidirectional
stick on my radar arch and it's done a pretty good job of pulling in wifi
signals.

-Bill Kearney

"Bill Kearney" wkearney-99@hot-mail-com wrote in message
...

True, and higher gain may also pull in a wider set of networks. You'd end
up listening to "too many" and get even worse performance. And the
radiation pattern from most of these antannae is shaped like a donut.
When
the boat is rocking that donut gets tilted up and down, in and out of the
coverage area. Higher gain antennae have a much narrower area of
coverage.
So any rocking with a typical 14db omni would render it almost useless.
Same deal goes for a directional antenna, if you swing on anchor there
goes
the coverage.
-Bill Kearney

Would there be any merit to fitting an antenna with a gimbal of sorts?

Shaun

Would there be any merit to fitting an antenna with a gimbal of sorts?

Probably not as the swing period would undoubtedly end up out of sync. A
powered gyro stabilized setup would be a more likely solution. That's what
they use in the satellite TV dishes.

Shaun Van Poecke wrote:

Would there be any merit to fitting an antenna with a gimbal of sorts?

Most likely no...the strain of the coax would be greater than gimbaled
mass. Even if you attached an extension rod for greater mechanical
leverage, it might not synch up with the swells.

"Bill Kearney" wkearney-99@hot-mail-com hath wroth:

Depending on where you're planning on travelling and how you're anchoring
there would be different recommedations. I've had a 10db omnidirectional
stick on my radar arch and it's done a pretty good job of pulling in wifi
signals.

OK, so you went with the omni. Photos of what I originally suggested.
Might be useful:
http://802.11junk.com/jeffl/antennas/marine-omni/index.html

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

decaturtxcowboy schreef:

Would there be any merit to fitting an antenna with a gimbal of sorts?

Most likely no...the strain of the coax would be greater than gimbaled
mass. Even if you attached an extension rod for greater mechanical
leverage, it might not synch up with the swells.

I'm considering a wandy unit on my radar arch with an omni on top of
it...
The wandy is successfully used in marine environments on inshore
freightships.
Distances over 5 km's are reported with good connections.
http://www.wandy.nl/2voc.htm
The utp cable provides (also, next to the signal up and down) the 12v
and there is no long coax that eats a lot of dB's. Gimballing is a
thought but the specs mention a 60 degrees antenna beam width so I
doubt if gimballing will really make any difference. But I agree and
think it's worth a little test before I make the final choice regarding
gimballing it or not.
Like cowboy says gimballing it would be simpler with the "soft"
utp-cable than with the rigid coax.
Keeping the unit leveled at whatever swell could be achieved by adding
a low weight (if necessary).
I intend to make the buy in a few weeks, if the firm allows me to test
it before buying it...
I'll write anything worth reporting to this NG.

Regards, Len.

"Jeff Liebermann" wrote in message
...
"Bill Kearney" wkearney-99@hot-mail-com hath wroth:

Depending on where you're planning on travelling and how you're anchoring
there would be different recommedations. I've had a 10db omnidirectional
stick on my radar arch and it's done a pretty good job of pulling in wifi
signals.

OK, so you went with the omni. Photos of what I originally suggested.
Might be useful:
http://802.11junk.com/jeffl/antennas/marine-omni/index.html

Yes, that's more or less just the sort of setup I went with. I went with
using a PVC extension to raise it above the radome. I went with using a PVC
end cap that I drilled through to mount the N connector. Then I've got a
thin gauge lead running down to the WRT54G mounted just underneath the
mount, tucked inside the arch. From there I run 12v power and wired
ethernet down into the cabin. Wired ethernet into a switch and power to the
ship's systems via a fuse. Worked quite well. Using it was simple, fire up
the laptop and surf to the router in the arch to select a shore SSID. There
were only a rare few situations where it wasn't possible to pickup a
reasonably strong signal. For this upcoming season I'm considering making
use of a PCMCIA modem bridged to a cellular network.

Bill Kearney wrote:

For this upcoming season I'm considering making
use of a PCMCIA modem bridged to a cellular network.

Hi, Bill,

Are you considering a modem because of lack of stations available, or
to be
able to do your internet under way, or some other reason?

I'm waiting for my Linksys 54GL to arrive (prolly today) to breadboard
the
LiteStation2 and see if I can't duplicate your results before swapping
out
the Senao on the mast...

In that case, I'd probably put my Vonage (VoIP telephony) unit on a Lan
port, and specify it for DMZ in order to get the most possible
bandwidth, rather than trying to have it do the router job. However,
even with the crappy Senao on the top of the mast, last weekend I got
more than 3 miles with it (over POE direct to the computer), while
under sail (albeit minimal heel).

For those not seeing my setup, it's an 8.5dBi omni stick antenna on
which Jeff has previously discussed reception and output patterns,
mounted to a cast aluminum NEMA box 62 feet in the air, powered and
data-fed over POE rather than separate wires or worse, coax with its
inevitable huge losses at that distance. Nonetheless, it seems to work
adequately, other than when we're over the AP I'm trying to reach (the
site is very close), in which case the small downtilt in the antenna
pattern doesn't get far enough down before it overshoots the target.
Of course, since I'll never use a marina, that won't be a problem once
I leave, in about a week...

L8R

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Are you considering a modem because of lack of stations available, or
to be able to do your internet under way, or some other reason?

Yes.

When there's no signal it'd be nice to be able use the cell network service.
No sense bothering with using that if I can get wifi. I'd like to have the
option.

That and as you've discovered, if you're "too close" to the base station it
can be tricky to get a reliable connection when the antenna's pattern
"misses" it.