"Wilbur Hubbard" wrote in message
anews.com...
I have personal experience with respect to this topic. Putting a wi-fi
antenna at the masthead is the WRONG thing to do. You don't want it high
up. You want it low down. It gets better reception low. The signals seem
to be stronger low. Mount a good amplified antenna at deck level for the
best reception. No need to worry about long lengths of co-ax at all.

Here's a good antenna that works well and is priced reasonably.
http://www.radiolabs.com/products/wi...ne-antenna.php

Wilbur Hubbard


If your antenna is vertically polarized you could see a 3 dB increase in
signal if it placed over a conducting ground plane such as salt water. This
is explained by the theory of images, which in effect doubles the antenna
gain toward the horizon. If the antenna is horizontally polarized the
radiation pattern become directed more skyward and there is an associated
decrease in gain toward the horizon. Wilbur, you have a keen sense of
observation.

I think it would be wise to learn something about 2.4ghz wave propagation
and the Fresnel effect before you make that statement. If you just want a
couple of hundred yards range deck mounting is fine but for 2 miles plus you
need to be UP.

By far the best solution is a waterproof wifi bridge at the masthead
connected by Ethernet with POE to a hub. Long range because there is
minimal coax loss and a wide Fresnel zone.

--
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

"Wilbur Hubbard" wrote in message
anews.com...

"Bob Crantz" wrote in message
...

"Wayne.B" wrote in message
...


The potential problem is
the long run of cable up the mast which will create a lot of signal
loss even with the very best LMR400 cable.

That cable has a loss of about 6 dB/100 ft at WiFi frequencies. A
colinear antenna can have gain way in excess of the loss and maintain an
isotropic pattern in the horizontal plane. Figure 50' of cable with 3 dB
of loss added to a 9 dB gain antenna is a net gain of 6 dB. It could work
out quite well. One has to consider the entire system, not just isolated
elements. This is a much cheaper and more reliable solution than an
active bridge up on the mast head.

Glory!


I have personal experience with respect to this topic. Putting a wi-fi
antenna at the masthead is the WRONG thing to do. You don't want it high
up. You want it low down. It gets better reception low. The signals seem
to be stronger low. Mount a good amplified antenna at deck level for the
best reception. No need to worry about long lengths of co-ax at all.

Here's a good antenna that works well and is priced reasonably.
http://www.radiolabs.com/products/wi...ne-antenna.php

Wilbur Hubbard

"Bob Crantz" wrote in message
...

"Wilbur Hubbard" wrote in message
anews.com...
I have personal experience with respect to this topic. Putting a wi-fi
antenna at the masthead is the WRONG thing to do. You don't want it high
up. You want it low down. It gets better reception low. The signals seem
to be stronger low. Mount a good amplified antenna at deck level for the
best reception. No need to worry about long lengths of co-ax at all.

Here's a good antenna that works well and is priced reasonably.
http://www.radiolabs.com/products/wi...ne-antenna.php

Wilbur Hubbard


If your antenna is vertically polarized you could see a 3 dB increase in
signal if it placed over a conducting ground plane such as salt water.
This is explained by the theory of images, which in effect doubles the
antenna gain toward the horizon. If the antenna is horizontally polarized
the radiation pattern become directed more skyward and there is an
associated decrease in gain toward the horizon. Wilbur, you have a keen
sense of observation.


Thanks. I can't help but be brilliant.

From the spec sheet: http://www.radiolabs.com/downloads/WaveRV.pdf

vertical beamwidth - 35 degrees
horizontal beamwidth - 360 degrees.

Wilbur Hubbard

"Glenn Ashmore" wrote in message
...
I think it would be wise to learn something about 2.4ghz wave propagation
and the Fresnel effect before you make that statement. If you just want a
couple of hundred yards range deck mounting is fine but for 2 miles plus
you need to be UP.

Bullocks. I happen to know by personal experience that low is better. Even
the manufacturer recommends deck top mounting.

By far the best solution is a waterproof wifi bridge at the masthead
connected by Ethernet with POE to a hub. Long range because there is
minimal coax loss and a wide Fresnel zone.

Bullocks again. KISS! Keep it simple, stupid. The more complicated it gets
the more failure prone it is. What happens to any antenna at the masthead at
anchor and even moreso under way? You have wind shaking it around, You have
the roll and pitch of the boat swaying it around. You have the heel pointing
it in all the wrong directions. You have static electricity going on at the
mast head. And watch out for any nearby lightning strike. WIPEOUT!

I am a sailor. I've been a sailor most of my life. I know what works and
your ideas won't! For lubbers maybe but for sailors, forget all about it.

And, BTW. What's with the top-posting? If you can't even learn how to post
correctly why is it you think people should take you seriously about
anything else?

Wilbur Hubbard

"Glenn Ashmore" wrote in message
...
I think it would be wise to learn something about 2.4ghz wave propagation
and the Fresnel effect before you make that statement. If you just want a
couple of hundred yards range deck mounting is fine but for 2 miles plus
you need to be UP.

By far the best solution is a waterproof wifi bridge at the masthead
connected by Ethernet with POE to a hub. Long range because there is
minimal coax loss and a wide Fresnel zone.

The pattern of coverage from the antenna is crucial. Something with a high
gain might work great when you're a mile or two offshore, but will work
horribly when you're in a marina. The pattern from most omnidirectional
antenna resembles a 'donut'. The higher the gain the 'wider' the donut will
be, but it'll be more compressed vertically. When you compress it this way
you become more susceptible to signal loss from wave motion. You're tipping
the pattern away from the intended source. I'm no RF-weenie so forgive my
use of layman's terms.

The other downside to picking up distant signals is picking up TOO MANY
distant signals. Being able to grab a signal from a mile offshore is one
thing. But using that same setup while in an anchorage that has several
wireless networks will result in poorer network throughput. Higher power
sucks too, not just for you but for the other networks you're interferring
with.

After dealing with these issues for two seasons I decided it was a lot less
hassle to just get a cellular network data card. I pop the card into the
router and it's DONE. No fiddling, no leeching a wifi signal from someone's
unsecured network, etc. It "just works". I still have the wifi gear and in
the unlikely event I'm in an area not covered I'll certainly use it as a
fallback.

-Bill Kearney

On Wed, 2 Apr 2008 15:25:43 -0400, "Glenn Ashmore"
wrote:

By far the best solution is a waterproof wifi bridge at the masthead
connected by Ethernet with POE to a hub.

I thought I said that. :-)

I know it works for me.

On Wed, 2 Apr 2008 15:37:08 -0400, "Wilbur Hubbard"
wrote:


"Glenn Ashmore" wrote in message
...
I think it would be wise to learn something about 2.4ghz wave propagation
and the Fresnel effect before you make that statement. If you just want a
couple of hundred yards range deck mounting is fine but for 2 miles plus
you need to be UP.

Bullocks. I happen to know by personal experience that low is better. Even
the manufacturer recommends deck top mounting.

All worked out for you he
http://www.cisco.com/en/US/products/...ence_list.html

I use the WaveRV marine antenna. Near metro, etc. areas I can get
adequate 'signal' 2-3 miles off the NE US coast. I have it mounted on
the stern rail ... seems to work better there.

"RichH" wrote in message
...
I use the WaveRV marine antenna. Near metro, etc. areas I can get
adequate 'signal' 2-3 miles off the NE US coast. I have it mounted on
the stern rail ... seems to work better there.


Thank you for telling it like it is. Experience under actual sailing
conditions trumps armchair bull**** every time.

Wilbur Hubbard

(Eliminating a lot of BS)

Are you sure you are not related to Jax?

I am a sailor too. Been sailing for 40 odd years now but I specify and
install long distance WIFI links as part of the job I do to pay for my
sailing. A bit over 60 systems to date including an island wide network of
anchorage hot spots for a pay for use operation in the Caribbean and a
private 9.5 mile link between Red Hook, St. Thomas and Little Thatch Island
.. I get paid well and I don't get many complaints. I have some idea what I
am talking about and, after monitoring a number of your posts, I have
concluded that you sir have a mouth in dire need of a good treatment of
Preparation H.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com