WIFI antenna needed: 33 days out
- Thread starter Dean5735
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The wavelength of a Wifi signal is small enough that if the antenna is a foot or more away from most metal object will put the objects in the far field of the antenna--metal boats (faraday cages) excluded.
Food for thought: neither an air card or an iPhone will allow you to stream video (hulu or netflix) without an 3G connection. Rural america uses E networks--not fast enough. However the cheap alfa 1 watt unit and a 9dBi antenna will allow you to stream video if the connection is adequate. It seems that many marinas now have WiFi (I am typing this message from a transient slip in a stop-over marina using the alpha WiFi device and a 9dBi antenna down below). However, you can not count on a WiFi signal to be available. I use my alpha WiFi device whenever possible and my Verizon air card whenever I cannot receive a WiFi signal. I live on my boat. I don't want a TV aboard because I don't have the patience for comercials. Video streaming is the wave of the future.
I use this. Very happy. If there is a signal, it will get it. Plugs into USB on computer. I run it up the flag halyard or you can mount it on an antenna mount:
http://www.radiolabs.com/products/wireless/captifi-wifi-antenna.php
http://www.radiolabs.com/products/wireless/captifi-wifi-antenna.php
Antenna height requirments
An antenna has two beam components, horizontal and vertical. Most of us are familiar with the omni directional antenna which transmits in a 360 horizontal arc. It also has the property of having a varying signal strength in the vertical plain. So, for instance, directly above or below the antenna you don't get much reception and when you are in line with it vertically you get a strong signal.
For a long range situation (at sea?) you would want an antenna mounted as high as possible so the antenna can physically see the base over the curve of the earth from as far away as possible. Now come into port and note that that base antenna is only 300 ft away from your mast head antenna. The vertical angle from the mast top (50') antenna to the base is (inv tan(50/300)=10 degrees. If you have a vertical beam width of less than +- 10 degrees from the horisontal you are going to have trouble connecting as your antenna is trying to operate in a less sensitive part of it's beam. The higher the gain on your omni antenna the narrower the vertical beam width. You do get a plus when in port by being closer (stronger signal) to the base unit so this does tend to offset any vertical beam issues.
What I glean from this is:
Get the antenna as high as practical if max range is important
Don't park right next (less than 1.5X mast height) to the base station antenna unless your antenna is at deck level
Balance vertical beam (antenna gain) width range extension and antenna height (sight angle) to get a solution that works for how you typically use your connection.
An antenna has two beam components, horizontal and vertical. Most of us are familiar with the omni directional antenna which transmits in a 360 horizontal arc. It also has the property of having a varying signal strength in the vertical plain. So, for instance, directly above or below the antenna you don't get much reception and when you are in line with it vertically you get a strong signal.
For a long range situation (at sea?) you would want an antenna mounted as high as possible so the antenna can physically see the base over the curve of the earth from as far away as possible. Now come into port and note that that base antenna is only 300 ft away from your mast head antenna. The vertical angle from the mast top (50') antenna to the base is (inv tan(50/300)=10 degrees. If you have a vertical beam width of less than +- 10 degrees from the horisontal you are going to have trouble connecting as your antenna is trying to operate in a less sensitive part of it's beam. The higher the gain on your omni antenna the narrower the vertical beam width. You do get a plus when in port by being closer (stronger signal) to the base unit so this does tend to offset any vertical beam issues.
What I glean from this is:
Get the antenna as high as practical if max range is important
Don't park right next (less than 1.5X mast height) to the base station antenna unless your antenna is at deck level
Balance vertical beam (antenna gain) width range extension and antenna height (sight angle) to get a solution that works for how you typically use your connection.
Dean,
Have the below on order to arrive this next week. Know it is steep on price, but personally know a couple of boats that use it and are getting up to 5 easy miles of reception. Hopefully in a couple of weeks I will be able to provide better advice.
http://www.islandtimepc.com/marine_wifi.html
Have the below on order to arrive this next week. Know it is steep on price, but personally know a couple of boats that use it and are getting up to 5 easy miles of reception. Hopefully in a couple of weeks I will be able to provide better advice.
http://www.islandtimepc.com/marine_wifi.html
Dean,
Just got the Island Time PC WiFi setup in my house this morning. Install and setup is relativity easy. Suggest not using browser Chrome for setup. Spoke with Bob at Island Time and he advised there is a bug in Chrome that makes you setup a field that is not needed. Use Firefox or IE.
Using my built-in wireless in the laptop I could see my router and two others. After setting up Island Time I could see 15 other routers in the area. Based on this limited test, I should not have any problems getting a signal as I proceed south. I will be taking it to the boat by this weekend and let you know what kind of signal strengths I see.
Just got the Island Time PC WiFi setup in my house this morning. Install and setup is relativity easy. Suggest not using browser Chrome for setup. Spoke with Bob at Island Time and he advised there is a bug in Chrome that makes you setup a field that is not needed. Use Firefox or IE.
Using my built-in wireless in the laptop I could see my router and two others. After setting up Island Time I could see 15 other routers in the area. Based on this limited test, I should not have any problems getting a signal as I proceed south. I will be taking it to the boat by this weekend and let you know what kind of signal strengths I see.
Our long cruise is still in the dreaming stage, but all this wifi info is very interesting.
Question for MJWarner and others - is the halyard-raised antenna subject to disruptions or dropouts if the moored boat is rolling or antenna is blowing in the wind?
Question for MJWarner and others - is the halyard-raised antenna subject to disruptions or dropouts if the moored boat is rolling or antenna is blowing in the wind?
update to Island PC WiFi
Currently sitting on the boat at the dock. Normally, we see about 3 stations with the marina being one of them. Depending on how many masts there a between me and the office antenna we get dropouts. With the Island PC antenna I'm seeing 21 routers in the area, not all are wide open but there has been a big improvement in the signal. This will be a winner...
Currently sitting on the boat at the dock. Normally, we see about 3 stations with the marina being one of them. Depending on how many masts there a between me and the office antenna we get dropouts. With the Island PC antenna I'm seeing 21 routers in the area, not all are wide open but there has been a big improvement in the signal. This will be a winner...
I just received and set up the Alfa AWUS036NH 2000mw transceiver with a 9dbi antenna (direct connect, no lossy antenna wire) plus a 5 meter powered USB cable. First tests look good.
Here are my results from a variety of setups-
Sitting at my home, with my internal laptop transceiver I receive 3 APs with my own at a SNR of 37. SNR is the Signal to Noise Ratio. Higher is better.
For the last couple of years I have been using an external USB transceiver sold by Keenan. It is the EnGenius EUB-362 and it has 200mw output. I have used it with an external antenna of 7dbi.
With this EnGenius setup at my home I get 6 APs with my own at a SNR of 48. That is an increase of 11db in signal strength.
With the new Alfa AWUS036NH 2000mw transceiver with a 9dbi antenna plus a 5 meter powered USB cable, I am receiving 8 APs with my own at a SNR of 53. That is an increase of 5db in signal strength over my EnGenius external transceiver.
My experience with the EnGenius is that while I can often connect to a unsecured AP from my sailboat satisfactorily, just as frequently the AP is just too weak to connect and stay connected long enough to grab email. Hopefully with this new Alfa transceiver and slightly stronger antenna I will be able to have better signal reliability.
Here are my results from a variety of setups-
Sitting at my home, with my internal laptop transceiver I receive 3 APs with my own at a SNR of 37. SNR is the Signal to Noise Ratio. Higher is better.
For the last couple of years I have been using an external USB transceiver sold by Keenan. It is the EnGenius EUB-362 and it has 200mw output. I have used it with an external antenna of 7dbi.
With this EnGenius setup at my home I get 6 APs with my own at a SNR of 48. That is an increase of 11db in signal strength.
With the new Alfa AWUS036NH 2000mw transceiver with a 9dbi antenna plus a 5 meter powered USB cable, I am receiving 8 APs with my own at a SNR of 53. That is an increase of 5db in signal strength over my EnGenius external transceiver.
My experience with the EnGenius is that while I can often connect to a unsecured AP from my sailboat satisfactorily, just as frequently the AP is just too weak to connect and stay connected long enough to grab email. Hopefully with this new Alfa transceiver and slightly stronger antenna I will be able to have better signal reliability.
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Bob
I just did a temporary clamp to the davits. I won't make it permanent until next week, but the davit looks like a good out of the way place for it.
I just did a temporary clamp to the davits. I won't make it permanent until next week, but the davit looks like a good out of the way place for it.
You can't just throw up an antenna and connect it via coax. A coax for WiFi over 3 feet will quickly cause enough signal loss to make the antenna useless. So that leaves you with a USB cable or Cat5. A USB cable MUST be an ACTIVE cable and even then the length will be limited. Cat5 will pretty much be unlimited. The best unit for running a Cat5 is the Bullet 2HP, not the M2HP. Here is the set up we have been using for over two years now and will pick up a signal miles away:
http://tinyurl.com/dcam3r
http://tinyurl.com/m9gg8z
http://tinyurl.com/dcam3r
http://tinyurl.com/m9gg8z
If I understand this thread correctly - then it is about using someone elses unsecured network for free. Generally, most businesses like coffee shops 'expect' that you are a customer if you are going to use their network. Of course, if they are dumb enough not to secure their network - what do they expect - and what intent are they conveying by failing to secure their network?
Using someone elses network without permission seems to be a legal nightmare of incomplete law and inadequate legal precedence. And, laws or legal interpretations that vary by location. One problem for a potential user is that others have been arrested for using an unsecured network.
Seems to be a messy gray area of law, and I am not a lawyer, but here are a couple of links:
1. http://blogs.pcworld.com/techlog/archives/000767.html
2. http://www.ibls.com/internet_law_news_portal_view.aspx?s=latestnews&id=1686
I am not sure what to do on this issue, except be aware before doing anything.
OC
Using someone elses network without permission seems to be a legal nightmare of incomplete law and inadequate legal precedence. And, laws or legal interpretations that vary by location. One problem for a potential user is that others have been arrested for using an unsecured network.
Seems to be a messy gray area of law, and I am not a lawyer, but here are a couple of links:
1. http://blogs.pcworld.com/techlog/archives/000767.html
2. http://www.ibls.com/internet_law_news_portal_view.aspx?s=latestnews&id=1686
I am not sure what to do on this issue, except be aware before doing anything.
OC
OldCat,
Yes, using an unsecured wifi connection without explicit permission is certainly a grey-area thing.
It's currently the case that MANY homes and small businesses have set up their wifi without securing them. And, most people won't notice casual unauthorized use of their wifi network unless they constantly monitor for unauthorized logins, or they experience reduced speed due to heavy unauthorized use. But such users would be most likely to secure their wifi... So, it is sort of a victimless situation in most cases...
Fortunately, more and more marinas, cafes and other public spots are themselves providing free wifi, which reduces the need to find and use other unlocked networks.
Yes, using an unsecured wifi connection without explicit permission is certainly a grey-area thing.
It's currently the case that MANY homes and small businesses have set up their wifi without securing them. And, most people won't notice casual unauthorized use of their wifi network unless they constantly monitor for unauthorized logins, or they experience reduced speed due to heavy unauthorized use. But such users would be most likely to secure their wifi... So, it is sort of a victimless situation in most cases...
Fortunately, more and more marinas, cafes and other public spots are themselves providing free wifi, which reduces the need to find and use other unlocked networks.
Actually there are lots of unsecured hotspots that are open to the public. One example are the public libraries where library members and non-members alike are allowed to use the wifi. Other places like bus, train, and airline terminals provide a similar service without expecting or requiring patronage. I agree that coffee shops and restarants expect that only their patrons will be using their service, but if they are unsecured they should realize that non-customers may also connect. One coffee shop in my town has a "free' wifi, but it is secured with a simple password. The password is posted in the shop for anyone to use.
When I was at Love Cove in Maine a couple weeks ago, I was surprised o find a really strong gang-buster signal called "Love Cove". It was so strong that someone must have provided it intentionally.
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