Boosting WiFi signal

[dsbentley]

I am sure many of you have experianced the same problems of poor WiFi reception on your boat. I am looking to boost the signal with the Syrens LITE for around $599 or the Seatech for $399. Has anyone had any good or bad experiance? Do they really help and how far away can you be to get a good signal?

Thanks David

[GySgt]

Power out is about equivalent to that of a good USB card.


First, start with the EnGenius USB adapter which retails for $50. This little black box works well due to it's 200 milliwatt power output (compared to a laptop internal device which only transmits in the 35-50 milliwatt range). The EnGenius hooks in to your USB port with the supplied USB cable and a small rubber duck style antenna threads on to the adapter.
While this device by itself may allow you to connect to a near by signal, but I also recommend getting an external antenna to mount somewhere outside on your boat.

Having tried multiple antennas, I think I would recommend something in the 8 to 10 decibel range. The db rating of the antenna describes the manner in which the antenna broadcasts its signal and at an 8 to 10 db rating, you are just about middle of the road.

The higher you mount you antenna, the better signal strength you will get, but for practical purposes, just mounting it outside at deck level is usually sufficient.

To connect the antenna to the USB adapter, you will need an antenna cable. These are custom made to the length you specify. The longer the cable, the less power you will have transmitting. Runs over about 40 feet are on the edge of requiring signal amplification or regeneration, so keep your cable length as short as possible.
Also, make sure you have the proper ends on your cable. For the above setup, you need a male N type on one end and a RP-SMA fitting on the other. Talk to your dealer to ensure you get the right ends!
Finally there is the installation. The adapter comes with a CD that is used to install the proper driver on your computer. As for the antenna and cable, hopefully common sense will prevail here and you will not mount your antenna inside the swing radius of your wind generator or something else equally inadvisable.
Good luck and happy surfing.

[sailingdog]

If you're on a laptop with a PCMCIA slot, get any of the 200 mW PCMCIA 802.11g cards that support an external antenna and get a decent patch type antenna with 6-9 dB gain and 90˚ angle of coverage. Should increase your range quite a bit.

The USB adapter GySgt pointed out should do the trick as well. Get a custom cable and don't use any couplers or gender changers, since each introduces a signal loss, and using two basically wipes out any possible gain in signal strength.

[groundhog]

Somebody told me the US standard requires a lower transmit power than the European standard for 802.11.

AND, that all of the wireless devices are actually built the same except that the ones shipped to the US have a jumper on them to set the lower TX power.

And that on some devices, all that's needed is to make this small mod and you get more range.

Anyone else hear of this?

[sailingdog]

Groundhog-

The legal maximum power rating for WiFi devices is 200 mW, regardless of country.

[capn_dave]

This type of antenna and reciever do the job. The only problem with the site I am about to show you, is their customer service. It's worse than (if that is possible) Raymarine. If you have a problem installing the drivers you won't get much help from these guys. Best thing to do is purchase it with a credit card and if you have a problem dispute the charge. You will get a response then, I promise. The good news is there are few problems with the installation and there are other makers of simlar products.
Here is the site http://www.radiolabs.com/products/wi...ne-antenna.php

Don't forget I warned you, It does work quite well. I know first hand and have helped people with their installations after Radio Labs would not.

Fair Winds

Cap'n Dave

[groundhog]

I am wondering about mounting the WiFi antenna on the masthead.
Wondering if the benifit of increased antenna height will be a net positive when combined with the added coax length..

This is the case with my TV antenna. Much better reception at the masthead dispite the wrong antenna and a 50/75 ohm missmatched adapter and the long cable.

[sailingdog]

I doubt that you'd get any benefit from going up that high. The signal loss is fairly significant on the cable that most WiFi antenna use. However, if you were using a USB-type WiFi card and got that say 16' up the mast, with the antenna another 10' above that, it would probably be a good improvement, since you'd only have 10' of antenna cable for signal loss.

Originally Posted by groundhog

I am wondering about mounting the WiFi antenna on the masthead.
Wondering if the benifit of increased antenna height will be a net positive when combined with the added coax length..

This is the case with my TV antenna. Much better reception at the masthead dispite the wrong antenna and a 50/75 ohm missmatched adapter and the long cable.

[chucklesR]

You can max out your system, but pay attention to the specs when you do so otherwise you are spending money on a futile dream. With a legal system of 200mW transmit and 23db antenna gain - operating in the -95db sensitivity range (a very good range for current technology - normal is 85 to 110) your maximum ranges, based on realistic conditions is also related to speed - the system will auto select the appropriate speed: Theorectical maximum ranges at various speeds are:
11 Mbps - 450m
5.5 Mbps - 600m
2 Mbps - 750m
1 Mbps - 1200m

So if what you are looking for is wifi on the Chesapeake, 2 miles from land you will never get there, max two way is 1.2 kilometers.

I'm a retired US Navy Radioman, from back when we had to actually calculate this stuff and tune by hand.

[sailingdog]

Chuckles-

With parabolic grid antennas, we've gotten more than 2 miles...

Just FYI—the 2005 record for a long distance WiFi link is 125 miles or so with 300 mW PCMCIA cards, which are stronger than legal IIRC, and 10' diameter dish antenna at each end, so you can manage some serious distance if you're properly equipped. I've managed over distances of 1+ nm using OTS equipment on my boat.