WiFi antennas

Stu Jackson · Jan 30, 2012

Yes, our does. Alfa - I forget the model #. Their website is pretty good. The special USB extender cable is a must.

JVB · Jan 30, 2012

A high gain antenna puts more output power or input sensitivity into a smaller "area". By area I mean a portion of a spherical surface surrounding the antenna. For instance a typical 3dB vertical wire sailboat antenna emits more power in a horizontal direction at the expense of less power 45º or more above or below horizontal. If you highly concentrate the input sensitivity then the antenna has to be aimed very precisely. (Like the dishes on satellite TV receivers.) Keeping an antenna precisely aimed is not possible on a bobbing boat without some kind of expensive active dynamic aiming system. So the answer about the usability of a 10 to 15 db gain WiFi antenna depends on the how much of a spherical angle the boat (and antenna) is swinging around in, the amount of directionality the antenna has, the sensitivity of the receiver, and the power of the transmitter. That's pretty much how you define the problem. But how to plug in what you know about the situation to get a more definitive answer is well beyond my knowledge.

Sumner · Jan 30, 2012

For us the answer has been an antenna and...

.... a radio on the antenna. We use the Bullet 2HP and have been connected over 4 miles with it depending on the shore connection also. I also use an alpha on trips in motels and such and it is ok, but not as powerful as the Bullet, at least for us.

I have more about the parts and such on our site here...

http://purplesagetradingpost.com/sumner/macgregor-navigation/WiFi-1.html

Also from my studies about a 7-9 db antenna is about the max you want to go with on a boat for the reasons stated by JVB,

Sum

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FourPoints · Jan 30, 2012

Antenna quality DEFINITELY matters. Cheap antennas almost never perform up to spec, and they have poor SWR properties that can blow out your radio in some cases. Additionally if the antenna is not grounded correctly it will build up static and eventually your radio will "go deaf" following a ESD from the antenna.

Ubiquiti (company that makes the aforementioned Bullet) is a pretty good company, and they understand ESD problems. I have installed many hundred of their embedded radios SR5 & XR5 to be precise) on cell towers and similar structures in the past, and only a few failures ever attributed to equipment failure (excluding their early generation SR9 radios, which had about a 30% failure rate).

The absolute best source in North America for WiFi antennas is Streakwave (http://www.streakwave.com/items.asp?Cc=ANT2.4OM&iTpStatus=0&Tp=&Bc=). Aside from being the largest (and for some of the brands they carry exclusive) distributor, the sales staff is very knowledgeable and experienced with outdoor WiFi gear. I have gotten to know many of the guys there over the years and they are all good guys there (except for one guy named Carl, and please if you call tell them I said that, and mention my user name on the forum here when you do).

If you are going to buy a WiFi antenna to mount on your spreaders or stern mount, call them for advice on the correct (and good quality) model for your application. They will be able to help with getting the correct antenna based on height, distance from shore you will be, and radio type.

The attached pictures show me on 1/9/2006 @ 350 ft up on a 410 ft tall communications tower installing the equipment shown in the last picture. Most of the equipment installed that day is still on that tower and in use to this day, and was purchased from Streakwave.

Cayennita · Jan 31, 2012

West Marine sells a wifi antenna that works well. I bought mine on line directly from the mfg. I lived aboard in Christiansted harbor and always had good signals. It's interesting how in Antigua or St. Martin you can get signals from Mega yachts that do not require passwords.

walt · Jan 31, 2012

I’m curious if you ever receive too many wifi signals with those high gain antenna's that it finally "overwhelms" the bandwidth? I.e., even though you’re receiving strong unsecured signal, it is real slow or hardly works because there are so many other strong signals?

I may just go buy something regardless and find out in my particular application..

monkeybars · Jan 31, 2012

this is 2012, every cell phone company sells smartphones with wi-fi hotspot, why would one go to all the trouble of modifing your boat in this day and age.??

Bill Roosa · Jan 31, 2012

I got the live-aboard situation. It is your house, I got it.
For the rest of us, What in Davy Jone’s Locker do you do with wifi on a boat???

A romantic evening starts out with a nice first person shooter game at sunset with a glass of fine French Wine followed with a relaxing Google search for that newest song by our favorite artist. We then finish the evening with streaming video of Hot Shots……?????!!!!!!

Clearly from the number of folks posting replies and lurking there is a demand for this stuff. I can’t for the life of me think of one single thing I’d do with a wifi connection while sailing.

Someone throw me a bone please.

Sumner · Jan 31, 2012

Bill Roosa said:
Clearly from the number of folks posting replies and lurking there is a demand for this stuff. I can’t for the life of me think of one single thing I’d do with a wifi connection while sailing.

Someone throw me a bone please.

Clearly it is going to depend on how long you are out for and what info you need.

For us usually being out a month or more having good weather info is very important. We get NOAA on the VHF all the time, but you are listening and writing down what they say and that can be a pain. If I can go on their site I can click on where we are are where we are going and get info like wave height and such for where I click. Using an application like what was posted by a user here a ways back that puts all kinds of info on the screen by just clicking on the map is great for us.

Also we have been going to different places with the boat and local info that we can find on the internet is great. Phone numbers and locations for marinas, restaurants, taxis, Home Depot, grocery stores, West Marine and such is a big help when you are in a new place for the first time.

I also work on our web site while on the boat and can upload updates to it.

Then there is the fact that I'm addicted to the Internet and need my daily fix and need to see what all of you guys are up to

.

Walt I never thought about your question, but have seen up to 30+ servers at time using the Bullet radio, but it doesn't seem to effect which one I'm connected to. With the Bullet you can adjust some of the power settings. Some times too much is not good. Also the really big deal is how good is the site's hardware that you are connected to. It is just as important that they 'hear' you and you hear them as it is a two way communication. I can often see servers, but they don't receive me. I've been connected to servers almost a mile away at the same speeds as at home on DSL and other times connections way under a mile are very slow. There again with the Bullet and the software that comes with it you have some control over some of this. Sometimes trying to get a connection and hold it is kind of like trying to get that radio signal from a station across the country on you AM/FM radio. Ruth doesn't have the patience for it, but I find it a challenge at times.

We had connections for most of our Florida trips with what we have with the exception of course in the 10,000 Island/Everglades area and one place in the Keys. We also didn't have cell phone coverage some of those places.

We have bought a LG Slider Android phone to try on the next trip with Virgin Mobile with either their $35 or $45 a month plan that is suppose to be unlimited WiFi, but if you read it after 2.5 gigs they might slow you down. For as much as I'm on the Internet 2.5 gigs is not a lot. We will save the time for when we really need the weather or other vital info and the rest of the time will still try and connect with our present WiFi setup,

Sum

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Bill Roosa · Jan 31, 2012

OK Sumner
I use my cruising guide for most of that and NOAA has the wave heights on the VHF in my local.

kloudie1 · Jan 31, 2012

Again, check out this thread.. Lots of reading there..
http://forums.hunter.sailboatowners.com/showthread.php?p=778369&highlight=WIFi

Shoaldrafter · Jan 31, 2012

the reason is

monkeybars said:
this is 2012, every cell phone company sells smartphones with wi-fi hotspot, why would one go to all the trouble of modifing your boat in this day and age.??

- - - - // - - - -

The topic is WiFi not just cell phones... while some of it applies to cell phones also.

The 'Why' is that some do work off their boats and need a good internet connection.

Not everyone connects via sat com connections.

Ed K

Forrest15112 · Jan 31, 2012

walt said:
I’m curious if you ever receive too many wifi signals with those high gain antenna's that it finally "overwhelms" the bandwidth? I.e., even though you’re receiving strong unsecured signal, it is real slow or hardly works because there are so many other strong signals?

I may just go buy something regardless and find out in my particular application..

It can overwhelm the band in a way. There is a bottom noise level called the noise floor. All radio signals must be stronger than the noise floor. When everyone and their grandmothers are sharing a limited amount of bandwidth, the interference increases, the noise floor goes up and everything has to run at full power to overcome the noise, but that increases the noise too. When there are 30 hotspots, the performance will probably drop off because of the noise. Throw in a few strong signals like 1000mW into a high gain omni-directional antenna and that causes even more noise. Your strong signal is connecting to some hotspots, but it's also radiating in the opposite direction causing noise. It all adds up to slower data rates for everyone trying to use wireless in the area.

If you recall, there was a thread about a company called Lightsquared that was trying to setup a high speed LTE wireless network adjacent to the GPS frequency band. The presence of their signals raised the noise floor of the adjacent band slightly, but enough that the cheap gps receivers flooding the market may not receive the gps signals very well in some places. The same principal is going on with accessing wifi over long distances. Highly directional antennas would be ideal, but not practical on a boat.

The problem is trying to access a hotspot from areas not intended to be covered. I recall some amateur radio guys I know taking a couple of old Satellite TV dishes and reconfiguring with wireless router & access point. They linked a remote site to one of their houses about 5 miles away I think. The dishes were not that high up either. This setup is less intrusive and harmful because it's like pointing two flashlights towards each other. No wasted signal in the opposite direction.

Anyway, The bullet setup is by far the best type. I'm not familiar with the product, but placing the radio right at the antenna eliminates the need for coax cable runs that, at 2.4GHz, is very lossy.

FourPoints · Jan 31, 2012

Forrest15112 said:
They linked a remote site to one of their houses about 5 miles away I think.

All of what Forrest15112 said is correct, however getting WiFi to work at 5 miles with directional antennas is childs play. I've personally done links of nearly 30 miles with hardware similar to the bullet. I know some people that have acheived links in excess of 100 miles. I beleive the record stands at roughly 155 miles for a point to point WiFi connection using large directional dish antennas.

CarlN · Jan 31, 2012

It's hard to tell from the post if the OP already knows this, but Wifi and long coax runs don't do well together. Not much signal will be left by the time you get to the base of the mizzen.

That's why the Ubiquiti products (which are great) put the electronics up the mast too attached directly to the antenna and use a cat5 computer network cable to get down the mast with no signal loss.

Carl

Gunni · Feb 1, 2012

monkeybars said:
this is 2012, every cell phone company sells smartphones with wi-fi hotspot, why would one go to all the trouble of modifing your boat in this day and age.??

Have you ever been to the Windward Islands? They barely have workable cell phone networks, and 3G/4G is a distant dream. It's all very charming and wonderfully off the grid.

RichH · Feb 1, 2012

I use a 'bitstorm bad boy extreme' (uses the ubiquity bullet as its base). Rarely, from Nova Scotia all the way down through the 'Leeward islands' do I have any connection problems ... although more and more wifi signals are becoming encrypted. This is an omni-directional antenna and I assume that I can get 'signal' up to 2-3 miles away (line of sight) for an antenna mounted high in the rigging.
http://www.bitstorm.com/products.html

Sumner · Feb 1, 2012

RichH said:
.. This is an omni-directional antenna and I assume that I can get 'signal' up to 2-3 miles away (line of sight) for an antenna mounted high in the rigging.

From what I've read the antenna doesn't have to be too high. 12-14 feet should do it as even with the earth's curvature you can get 3-5 miles that high. Some people report that if you are too high in the rigging and are in a harbor or slip close to a hot spot that you might actually not see them as your antenna is higher than theirs and the cone of transmission/reception is over their antenna.

Now saying that the height might help in some instances. I could pickup a server in Boca Grande while down in Pelican Bay about 4 miles (a slow connection). Then a storm came in and we moved to the other side of some Mangroves about 200 yards from where we where before and I couldn't pickup the signal. I think the Mangroves were just enough to block the weak signal and maybe if the antenna would of been another 5 feet or so we would of connected.

Our antenna on both boats is.....

... about 12-14 feet off the water. I just mention this to let people know that they don't have to get the antenna real high to have a successful WiFi connection.

If I was buying WiFi I'd go with Island Time PC...

http://islandtimepc.com/marine_wifi.html

.... Their kits are only about $50 or so more than piecing the whole thing together like I did from multiple sources and they will save you a lot of grief if you have never done this. Also they are sailors and really support their product from people's comments I've read on the cruising boards.

Using the Bullet and the software to best advantage is a little more complicated than going into the computer cafe and turning your laptop on and hooking up. Island Time will get you past that with their instructions,

Sum

[FONT=Arial, sans-serif]Our Endeavour 37[/FONT]

[FONT=Arial, sans-serif]Our Trips to Utah, Idaho, Canada, Florida[/FONT]

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[FONT=Arial, sans-serif]Mac-Venture Links[/FONT]

FourPoints · Feb 1, 2012

Sumner said:
From what I've read the antenna doesn't have to be too high. 12-14 feet should do it as even with the earth's curvature you can get 3-5 miles that high. Some people report that if you are too high in the rigging and are in a harbor or slip close to a hot spot that you might actually not see them as your antenna is higher than theirs and the cone of transmission/reception is over their antenna.

While this is sort of true, the difference between 12-14 and 20-30 feet (on the spreaders) will likely never cause this to be a problem. If you were to put the equipment 300 ft up then you would have a dead zone for about 1000 ft where most devices would not work (this is from actual experience and testing). The propagation patterns of antennas does not result in a hard edge to where the signal is and isn't, it reflects a boundary where the signal strength falls below a particular threshold. So even if you have an antenna with a 20 degree beam width, it will still project a signal 40 to 50 degrees off it's center plane, just at a weaker strength.

Since the times you are likely to encounter this height disparity between base station and your antenna are when you are close to the AP (the angle decreases with distance so to be far away and still out of the signal plane you have to be VERY high up), you will still have a plenty strong signal. It is true that you may be directing the majority of your RF energy over the top of the AP, but enough will reach it (and it's energy reach you) that you won't likely experience any degradation or connectivity problems.

The problem is that if you only have the antenna 12-14 up, then you are shooting through the hull / cabin of that big sport fisherman or tug boat between you and the AP. Double the height by putting the antenna up on your spreaders and you are likely shooting over the top of the other boats, and you will receive a much cleaner / stronger signal. Additionally the extra height above water will limit the degrading effects of multipathing caused by the signal reflecting off the water surface (think signal echos, they can be very bad for performance, or even destroy your ability to pass any traffic over the link).

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