Long-Distance WiFi Device

[chucktro]

Check out the following site for an excellent wifi booster. I have used model 300 for the past six months to connect to the internet with excellent results. I am not certain of the range which may be involved but I am able to connect to a wifi tower where ever I may be anchored on the lake.
www.rv2internet.com/

[Gashmore]

Paying $400 for a wifi box that doesn't publish power or receive figures is crazy when you can buy a proven 200mw EUB-362 with 92db receive that is the size of a pack of cigarettes and a good 9db antenna for under $100. If you are looking for a more permanent installation an EOC 3220EXT from Engenius with a 9db marine antenna cost Maybe $220. It is a 6x6x2 waterproof 2 lb box that puts out 400mw with 91db receive. Installed at the masthead with an Ethernet cable to the nav station will give you 11Mbs at 6 to 8 miles from a good shore signal and a full 54Mbs at a mile or more from a cheap AP in some one's vacation villa. (of which there are many left unsecured scattered all over the Caribbean.)

With any Wifi installation there are two unalterable rules when going for range: Keep the coax run as short as possible. at 2.4GHz even the best 1/4" diameter coax will eat half the signal every 23'. Get the antenna as high as possible to minimize obstructions within the Fresnel zone.

[Pelagic]

Originally Posted by Gashmore

With any Wifi installation there are two unalterable rules when going for range: Keep the coax run as short as possible. at 2.4GHz even the best 1/4" diameter coax will eat half the signal every 23'. Get the antenna as high as possible to minimize obstructions within the Fresnel zone.

So can anyone tell me what is the optimum height versus maximum cable length?

Surely it is a compromise with some guide lines from experienced users

[Gashmore]

The best solution is to get a high power waterproof wifi router/bridge and mount it on a spreader or at the masthead. Run an Ethernet wire down to your PC or an access point for local wifi. Power is supplied to the router up on the mast through the Ethernet line using POE (Power over Ethernet) from a little injector in the cabin.

Next best is a 200mw eub-362 and a 15' USB cable. When you want to use the Internet place the 362 on the cabin top with maybe 5' of LMR250 coax to a 9db marine antenna mounted on something like a Bimini bow. You will not get the eye popping range of 400 mw at the masthead but it will serve well out to maybe a mile or so from a good shore signal.

The idea is to send your data the longest distance through the ethernet or USB cable which do not loose power and keep the coax run as short as possible.

[Soft Air]

Gashmore quick question for you. I heard the 362 was preceded by a much better model by the same manufacturer, do you have any related info available?

Thanks in advance,

[Gashmore]

Engenius makes a 200mw PCMCIA card with an antenna socket that works pretty well. Similar to the SMC 2532. I had one for a while but you had to use LM100 coax to an antenna so any run over 5 or 10 feet ate a lot of signal. I carry a 362 and a 15' USB cable with me on charters and it does just about all I need. It will work out to about 1200 yards from Foxy's Access Point on Jost Van Dyke sitting on the cabin top with just the little 3db antenna that comes with it.

[wlearl]

Interesting! These kinds of threads always raise a lot of questions because they always compare items with small but significant differences. I suspect that the receiver front end is more important than the transmit power. And, antenna cable losses could sure be a killer. But, it would sure be nice to have 20 or so feet of cable on the antenna so it could be placed in an opportune spot.

The Alpha looks like a good choice but the double USB connection could be a bit of a problem for an installation like Chuck's. Could also use a 10 to 12 dB antenna.

[Gashmore]

Wifi is a two way street. The sum of transmit power and receive sensitivity for both ends have to be balanced. If you want to connect to a typical low power (60-65mw) domestic access point at some distance you have to have very good sensitivity but receive sensitivity is usually the problem. It is fairly easy to add power but once you get past about 93db sensitivity starts getting expensive.

USB is fine for a portable unit but the USB signal is limited to 15' unless you put an extender at each end. USB extenders do work. I have one running to the far end of my house to operate a pan/tilt camera mount but you add more up weight and may have problems supplying power to the remote extender unless the device at the far end has its own power supply.

That is why the Ethernet with POE to a remote router/bridge with a very short coax connection to a good 9db antenna is by far the best choice for a permanent installation. You don't have to worry about the length of an Ethernet cable on a boat unless maybe on Larry Ellison's Rising Sun and he probably gets a good discount and first rate installation support. :-)

Wiring up and configuring a bridge at the masthead to a single PC is pretty straight forward (well except maybe for the mast climbing part) but connecting it to a Wifi access point for a local wireless network adds to the complexity.

Incidentally, 9db is about as high as you should go for an antenna on a mono because any narrower beam width cause fading as the boat rolls. A cat can go up to 12db.

[Chuck Baier]

Originally Posted by Gashmore

USB is fine for a portable unit but the USB signal is limited to 15' unless you put an extender at each end.

Our unit works just fine with a 20 foot active USB cable attached to the 4 foot cable that comes with the unit and have easily reached 2 miles to pick up a very usable signal.

[GordMay]

Originally Posted by Chuck Baier

Our unit works just fine with a 20 foot active USB cable attached to the 4 foot cable that comes with the unit and have easily reached 2 miles to pick up a very usable signal.

In practice, the Universal Serial Bus (USB) specification limits the length of a cable between full speed devices to 5 meters (a little under 16 feet 5 inches). For a low speed device the limit is 3 meters (9 feet 10 inches).
Goto: USB.org - FAQ: Cables, Connectors, and Networking

The USB signals going in and out of an “Active” extension cable are buffered to assure signal quality and the meeting of the USB2.0 Electrical and Timing Specifications. Using passive cables for the purpose of extension will result in signal errors and is not recommended.

[Pelagic]

Thanks Gashmore. This will be my first time doing this so need a little more guidance. (And that is hard to find in the Philippines!)

I would like to do a permanent installation on the masthead (18m) so total cable length is about 25m.

Can you point me in the right direction for finding good equipment, router/bridge; antenna, cabling and what else is needed like software etc?

Who sells all the components and can provide an installation schematic so I can order, ship out for installation?

[tyrntlzrdking]

Outdoor AP/Client Bridge - EnGenius Datacom Products

[Beausoleil]

I opted for the Engenius EOC-8610S-EXT wireless client bridge/access point, which is IEEE 802.11/a/b/g capable (2.4/5GHz), in the off chance I come across an 802.11a system. Like the EOC-2610 and others, it's remotely powered via its Ethernet connection (POE).

The included software is not what I'd call top-notch - I'll investigate and see if I can overwrite it with dd-wrt, the excellent open source access point software. Do yourself a favor - if your hardware is supported by dd-wrt, install it. It unlocks all the capability built into most chipsets used by the big manufacturers, and adds LAN switching, VLAN, IPSec VPN, firewalling, secure management via SSH or SSL. It's like turning your consumer access point into an enterprise version...

[Chuck Baier]

look for the November issue of Bluewater Sailing for the details and how to of our WiFi set up.

[Evan]

And Ocean Navigator Sept 2008 issue has a nice article on how to make your own 9 dB antenna, with USB connection... for $35 or so.

Might be a good winter project.