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ArmyChief · 11-08-2010, 10:24

Jugo,

First off, I will not get into a argument over the device you have posted previously. looking at the bottom of the PDF, it appears you are biased since you are a seller of this device. However, I will make my commentes based solely on the "specs" and picture of your "flyer"

10 db OMNI-Directional antenna - Why in teh world, would a boater anchored, moored or at dock want to transmit and/or recieve ina 360 degree pattern from his/her location??? First, this is a WASTE of energy. Your WiFi point is in one direction. Second, using a omni-directional antenna does not offer rejection to unwanted signals/noise..like a directional antenna does. Lastly, a good bi-quad or cantenna offers more than 10 db increase..typically 12-16 db (BTW, every 3 db is a double in effective power)

Based on the "specs" inside your low-cost proto box is a ALFA AWUS036H type USB adapter..is I had to guess. it surely uses the same chipset. It may also even be a lower cost clone/knockoff.

Long distances over water are not something unheard of..even with lower wattage units. Wifi operates in teh microwave band...it is line of sight...open sea..is the perfect environment for that type of distances.

The USB extenders I have used work just fine with the Wifi USB adapters (ALFA AWUS036H )..IMHO is one of the best out there (as long as it is an original..It is also available for under $30 U.S)

(ArmyChief gets off his soapbox)

wad'nwind · 11-08-2010, 10:58

Quote:

Originally Posted by ArmyChief

Jugo,

First off, I will not get into a argument over the device you have posted previously. looking at the bottom of the PDF, it appears you are biased since you are a seller of this device. However, I will make my commentes based solely on the "specs" and picture of your "flyer"

10 db OMNI-Directional antenna - Why in teh world, would a boater anchored, moored or at dock want to transmit and/or recieve ina 360 degree pattern from his/her location??? First, this is a WASTE of energy. Your WiFi point is in one direction. Second, using a omni-directional antenna does not offer rejection to unwanted signals/noise..like a directional antenna does. Lastly, a good bi-quad or cantenna offers more than 10 db increase..typically 12-16 db (BTW, every 3 db is a double in effective power)

(ArmyChief gets off his soapbox)

In a certain point of view you are right with omni and directional, but...
If you mean a 120 or 90 deg. opening angle you are fully right with respect to the antenna. But when you mean an antenna with a small directional view angle like a cantenna or yagi or whatever, it is a drama when you behind your anchor and have 4x times or more an hour redirect your antenna. once Moored in a harbor to the jetty it will do o.k. with a yagi.

An antother issue is the coax problem. Almost evereyone offers thin coaxcables, even good quality types like Aircel-5 give with 5 meter length
allready 2,66dB (almost 3) loss. or Aircell-7 1,78 dB. In this example I take respectable quality coax, but ofter a worse type of coax is offered.

A 3rd argument is all the lose parts you have to setup, for some no problem, for other undesirible.

Further is everybody free building his own sollution with his own materials, good Initiatives are always welcome and encouraged.

ArmyChief · 11-08-2010, 11:07

Quote:

Originally Posted by wad'nwind

In a certain point of view you are right with omni and directional, but...
If you mean a 120 or 90 deg. opening angle you are fully right with respect to the antenna.

A cantenna has an approx 45 degree aperture. When you look at the distance from your vessel to the WiFi transmitting device...a 45 degree spread MORE than covers you..even with swinging on your moor/anchor for the most part (baring 180 degree current/wind changes)..then yes you may need to redirect your cantenna/yagi/bi-quad. A SMALL trade-off for the GREAT performance benefit.

Quote:

Originally Posted by wad'nwind

An another issue is the coax problem. Almost evereyone offers thin coaxcables, even good quality types like Aircel-5 give with 5 meter length
allready 2,66dB (almost 3) loss. or Aircell-7 1,78 dB. In this example I take respectable quality coax, but ofter a worse type of coax is offered.

Using USB instead of coax eliminates any loss!! (using an extender if needed). I do not recommend LMR cable (195, 200 or even 400) if a USB option is available

Quote:

Originally Posted by wad'nwind

A 3rd argument is all the lose parts you have to setup, for some no problem, for other undesirible.

Further is everybody free building his own sollution with his own materials, good Initiatives are always welcome and encouraged.

On this we can agree.

hellosailor · 11-08-2010, 11:15

" Why in teh world, would a boater anchored, moored or at dock want to transmit and/or recieve ina 360 degree pattern from his/her location??? "

Chief, I'm guessing you weren't in the Signal Corps? <G>

A directional antenna is a great idea if you are staked down to the ground. But if you are moored and you expect to swing 180 degrees twice a day during tidal flows or wind shifts--the omni is the only thing that will work without futzing around all day.

"A cantenna has an approx 45 degree aperture." No, not really. There are many cantenna designs and you can focus the beamspread to way less than 45 degrees. If your antenna has a 45d beamspread and mine has a 15d beamspread, remember that's a conical spread, and my beam now has aabout a NINEFOLD effective power increase. That's significant. Same power, but all focused in only 1/3 the height and 1/3 width.

USB is only one way to bypass problems with coax line loss, PoE (Power over Ethernet) is the other way, and you can easily run 100' of ethernet cable instead or worrying about USB. Ethernet is designed to do that job, USB is expressly not.

ArmyChief · 11-08-2010, 11:28

Quote: