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Thread: antenna power

  1. #1
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    Default antenna power

    does sticking a higher dbi antenna on a usb wifi dongle really make a difference? currently i have a 2dbi antenna and am thinking of getting a 9.5 dbi. would i see much difference in sensitivity or range?

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    Senior Member MikeCa's Avatar
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    I've seen it make a difference but I imagine the effect is dependent on the wireless hardware.

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    Senior Member Thorn's Avatar
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    Quote Originally Posted by cain#1 View Post
    does sticking a higher dbi antenna on a usb wifi dongle really make a difference? currently i have a 2dbi antenna and am thinking of getting a 9.5 dbi. would i see much difference in sensitivity or range?
    You'll get 7.5db of gain with the new antenna over the old antenna. If you don't know or understand what that means, STW for antenna information pertaining to gain.
    Thorn
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    i have a alpha awus036h and have just ordered a 1000mw usb adapter. these are the adapters i am planning on using the 9.5dbi antenna with. any thoughts?

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    Junior Member imported_freedom56's Avatar
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    I have the Alfa 500mW with a 9dBi antenna and i have tested it out to about 1500 feet. My co-worker says he has tested his out to almost 2000 feet. I haven't had any problems with my alfa and BT 4. it injects well and is fairly reliable.
    "One of the main causes for the fall of the Roman Empire was that, lacking zero, they had no way to indicate successful termination of their C programs."

  6. #6
    prowl3r
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    Quote Originally Posted by cain#1 View Post
    i have a alpha awus036h and have just ordered a 1000mw usb adapter. these are the adapters i am planning on using the 9.5dbi antenna with. any thoughts?
    Sure, shield your balls.

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    Senior Member Thorn's Avatar
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    Quote Originally Posted by cain#1 View Post
    i have a alpha awus036h and have just ordered a 1000mw usb adapter. these are the adapters i am planning on using the 9.5dbi antenna with. any thoughts?
    With a 9.5dBi gain antenna assumed to be held in a vertical orientation, you will see an increase in gain in the horizontal plane. At the same time, there will be a decrease in the vertical plane gain.

    Unless you a) define the proposed application of the wireless setup, and b) the transmitter power on BOTH ends and the receiver sensitivity (RF budget) at BOTH ends, and c) understand the math of RF communications, any "thoughts" will be ambiguous at best. So far you've only defined one transceiver and one antenna. That's less than half the equation.

    Quote Originally Posted by freedom56 View Post
    I have the Alfa 500mW with a 9dBi antenna and i have tested it out to about 1500 feet. My co-worker says he has tested his out to almost 2000 feet. I haven't had any problems with my alfa and BT 4. it injects well and is fairly reliable.
    This is exactly what I mean by ambiguous. Nothing against freedom56, but testing what out to 1500 or even 2000 ft? Without knowing the devices on the other end (and the corresponding RF budget), the RF path, and simply if this is in a TX or RX mode (or both TX and RX), the indicated range doesn't mean much.

    Hell, I've received 802.11b well over 7 miles with the right conditions, path, and antenna and know some people who have had 2-way links in the 25 mile range. I've also had times when the path precluded anything more then a couple of hundred feet with any antenna.

    Again, the bottom line is that none of those figures means anything unless you define the application and know the RF budget.
    Thorn
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    Junior Member imported_freedom56's Avatar
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    @ Thorn
    You are completely correct and i hesitated to even add my comments originally as there are so many factors that come into play when discussing radio frequencies. My setup will be different then the OP's. I am in no way an expert on this, however as I understand it, it is nearly impossible to duplicate the exact conditions of a wireless test due to the sheer number of variables.

    @ OP
    I suppose i should have merely mentioned that with my setup, I noticed better reception with my 9dBi antenna versus the stock antenna of course I have also read that many do not see a difference.
    "One of the main causes for the fall of the Roman Empire was that, lacking zero, they had no way to indicate successful termination of their C programs."

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    Senior Member Thorn's Avatar
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    Quote Originally Posted by freedom56 View Post
    @ Thorn
    You are completely correct and i hesitated to even add my comments originally as there are so many factors that come into play when discussing radio frequencies. My setup will be different then the OP's.
    Like I said, it's nothing against you, my problem was with the objectiveness of such answers such as "better reception". "Better" for you might be great, or it might be absolutely disappointing for the next guy who has different expectation. If you do the math, you know what you're going to get.

    Quote Originally Posted by freedom56 View Post
    I am in no way an expert on this, however as I understand it, it is nearly impossible to duplicate the exact conditions of a wireless test due to the sheer number of variables.
    Actually, that's not true. You can work out must of this stuff on paper and arrive at very accurate figures. Those figures can usually be duplicated in the field. It isn't rocket science, but it does require a knowledge of how RF waves propagate, and basic algebra. In other words, your average eighth grader can do this with a little time and effort.
    Thorn
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    Junior Member imported_freedom56's Avatar
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    Quote Originally Posted by Thorn View Post
    Actually, that's not true. You can work out must of this stuff on paper and arrive at very accurate figures. Those figures can usually be duplicated in the field. It isn't rocket science, but it does require a knowledge of how RF waves propagate, and basic algebra. In other words, your average eighth grader can do this with a little time and effort.
    Haha, looks like I have some learning to do. Guess this is as good a time as any to research a little more on this subject. I always assumed it was more akin to rocket science (and we all know what happens when we assume). Thanks for pointing that out. I am intrigued enough to look into it know.
    "One of the main causes for the fall of the Roman Empire was that, lacking zero, they had no way to indicate successful termination of their C programs."

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