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Thread: Can somone explain Highpower USB wireless devices to me

  1. #1
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    Question Can somone explain Highpower USB wireless devices to me

    I was wondering how these high-power wireless devices can have that OUTPUT power.
    I mean they get their supply from an USB port so 0.5 x 5 = maximal 2.5 watts INPUT and some of this is consumed by the chip.

    The AWUS036NH claims to have 2 watt output?
    That would mean an super rendement!

    And how about the setting of your USB port? how to set it to high-power?
    I thought 100 ma is default.
    How do i check the USB high-power setting?

    Also the power setting can only be set to max 30 dbm (region setting at BO) that would be 1 watt.
    How do i get that extra 3 db? to double it to 2 watts?


    For the Alfa AWUS036H the power specs are 30 dbm but that is at CCK and is this not a backward-compatibillity mode?
    With OFDM it is only 24 dbm (about 251 milliwatts)


    greetings

  2. #2
    Member Mr-Protocol's Avatar
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    Default Re: Can somone explain Highpower USB wireless devices to me

    This is a Back|Track 4 forum. Not electronic devices 101.

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    Default Re: Can somone explain Highpower USB wireless devices to me

    Taken from usb.org since I am not a EE.

    "You may connect high power devices to self powered hubs only and low power devices to either bus or self powered hubs.
    High power devices are devices that draw more than 100mA from the USB power line, low power devices are ones that draw 100mA or less. High power devices are typically bus-powered cameras, bus powered hubs. Low-power devices are typically mice, keyboards, joysticks, and any devices that come with their own power supply (also known as self powered devices). Most general purpose hubs come with their own power supply as well and therefore are self powered. A subset of hubs called bus powered hubs gets power from the bus and therefore has the limitation of only supporting low power devices."

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    Default Re: Can somone explain Highpower USB wireless devices to me

    You weren't very clear when you were showing us your math:
    I mean they get their supply from an USB port so 0.5 x 5 = maximal 2.5 watts
    So I tidied it up for you:
    Code:
    Watts are Amps * Volts, so when calculating USB wattage:  W = (.5mA)(5V) = 2.5W
    Erego, you do indeed have a 2.5 Watt input per USB connection to the USB device. However, the AWUS036NH uses 5V + 5%; that's 5.25V by my math. So, the AWUS036NH actually consumes approximately
    Code:
    W = (.5mA)(5.25V) =
    2.625W.

    ... some of this is consumed by the chip.
    Actually, all of it is consumed by the device. Some for the chip, some for other parts, some discarded. What you're missing here, is that some of that energy is being converted to radio and then modulated varyingly. See the fol. refs: BPSK, QPSK, CCK, and OFDM. Internal components, such as capacitors, transistors and resistors manage the output power. That's how you get the 2 Watts.

    how to set it to high-power?
    YOU don't set your ports to high power, the connected device requests more units from the USB host. Each unit is 100 mA, and on USB 2.0 the max number of loads that can be requested is 5; therefore you can have a max output of 500 mA. Using two ports to power this device obviously doubles its input to the device to 1000mA, or simply 1 Ampere.

    I thought 100 ma is default
    Indeed it is. Each USB port starts at 100mA. Under the USB 2.0 specs, additional units (100mA each) can be requested from the guest device, up to a maximum of 5 total units (500mA)

    I'm a little lost where you go off with decibels:
    Also the power setting can only be set to max 30 dbm (region setting at BO) that would be 1 watt.
    How do i get that extra 3 db? to double it to 2 watts?

    For the Alfa AWUS036H the power specs are 30 dbm but that is at CCK and is this not a backward-compatibillity mode?
    With OFDM it is only 24 dbm (about 251 milliwatts)
    Anyway, decibels (dB, dBm, dBmW, dBi) is a measure of gain (sensitivity) at the antenna. You don't get decibels off the USB port, and depending on the modulation, you may only be able to set the device to be as sensitive as it need be. Too much gain causes 'clipping' to occur on the incoming signals; too little gain, and you get dropouts. See this page, or this page to understand what I mean a little better.

    Further, different modulations are for different 802.11 standards; for example CCK is included for compatibility with 802.11b standards.

    But Mr. Proto's right. This is a BT4 forum. PM me if you need more.

    Cheers,

    xX_Spiidey_Xx
    Last edited by xX_Spiidey_Xx; 02-05-2010 at 09:42 PM. Reason: BT4 addon... he beat me to the punch.
    thou shalt treat all computers as thou wouldst treat thyself, for thou art the creator of thine own problems.

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    Default Re: Can somone explain Highpower USB wireless devices to me

    Your all missing the point.

    The quoted output power is NOT the output from the card itself but actually the ERP (Effective Radiated Power) which includes any gain provided by the antenna supplied.

    The advertising is a bit of a con, but there you go.....

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    Default Re: Can somone explain Highpower USB wireless devices to me

    Pwnd. Thanks for explaining, balding_parrot!
    thou shalt treat all computers as thou wouldst treat thyself, for thou art the creator of thine own problems.

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    Default Re: Can somone explain Highpower USB wireless devices to me

    Thanks for your answer.
    I get the notion from reactions that my question is judged to be out of place here.

    i leave it at the suggestion that the power is EIRP, that would explain most of it.

    greetings

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    Default Re: Can somone explain Highpower USB wireless devices to me

    Quote Originally Posted by 100monkeys View Post
    Thanks for your answer.
    I get the notion from reactions that my question is judged to be out of place here.

    i leave it at the suggestion that the power is EIRP, that would explain most of it.

    greetings
    I don't think there was anything wrong with your question, that is why I approved it in the first place. Second I think you got some good answers so what is the problem?
    Granted this may not be the best place on the net for that type of question but we will generally answer and help those who ask genuine questions that are not directly against the forum rules.

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    Default Re: Can somone explain Highpower USB wireless devices to me

    Quote Originally Posted by Archangel.Amael View Post
    I don't think there was anything wrong with your question, that is why I approved it in the first place. Second I think you got some good answers so what is the problem?
    Granted this may not be the best place on the net for that type of question but we will generally answer and help those who ask genuine questions that are not directly against the forum rules.
    Thanks for that.
    No problems.


    greetings

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    Default Re: Can somone explain Highpower USB wireless devices to me

    This is what the USA FCC has to say about the subject...

    Got this off a review on amazon for the ALFA AWUS036NH. This was entered in as a response to a one star rating.....

    This is for anyone that wants to gain a little understanding (confusion?) of radio systems

    In reply to an earlier post on Dec. 5, 2010 12:50 PM PST

    Larry Butler Ampz Electronics says:

    The full test reports of both are online. The REAL output power of 036H is only 58mw, not 1000mw and 036NH is much better at 200mw, not 2000mw. Your laptop will be lucky to put out 20mw into its horrible PC board antenna buried behind the display so these units are a vast improvement from the embedded radio in any laptop/netbook.

    FCC regulations state that the EiRP (Equivalent isotropically radiated power: adapter + antenna - cabling loss) of ANY wifi adapter to keep the cable, phone and cellphone lobby happy is limited to 1 watt (1000mw) EiRP or 30 dBi. (See dBm to Watt Conversion Table.)

    The realtime test reports were way below that number which is why they were approved.

    There is no 2 watt wifi adapter in the USA. It would never pass FCC acceptance testing.

    Even a lie, my 036NH and 036H are fantastic units for the price and performance is very impressive.

    Those wanting the secret schematic will find it down-loadable as pdf on the 036NH at the FCC website above.

    The RF power amplifier is rated at +26dbm (about 400mw) and the whole thing barely gets warm in heavy use, which is very easy on the laptop batteries.

    ---------------------------------------------------

    End of technical explanation.....

    Of course add in a good dipole array antenna and your dBi power dramatically rises. Then you can convert the maximum combined db to watts to get an antenna watt output rating..... I have one on 'the boat' that adds up to ~42 dBi or ~16 Watts for nearly 5 miles of connect-ability.....

    --------------------------------------------------------

    The FCC site search and reports:

    https://fjallfoss.fcc.gov/oetcf/eas/...ericSearch.cfm

    using UQ2 which is Alfa's manufacturer designation on the system. Hope the webpage comes up when I post this. The 036H is:

    https://fjallfoss.fcc.gov/oetcf/eas/...39;UQ2AWUS036H'

    and the 036NH is:
    https://fjallfoss.fcc.gov/oetcf/eas/...='UQ2036NH'

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