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Thread: Startup deploying new wireless network over TV white space

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  1. #11
    Join Date
    Nov 2007
    Location
    Rolla, MO
    Posts
    72

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    I bet these guys were among the first to get their hands on a few Pervices Phi Boards. Good to see new development, nevertheless.
    Sterling Coffey, N0SSC, ARRL Youth Editor, WEEE President and EE Junior
    Missouri University of Science and Technology
    Rolla, MO

  2. #12
    Join Date
    Nov 2007
    Location
    Rolla, MO
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    72

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    Quote Originally Posted by KB9MWR View Post
    A few hams have been experimenting with doing this on the 70 cm ATV sub-band.

    http://kb9mwr.blogspot.com/2011/03/h...0-430-mhz.html

    It will be presented by David Bern, W2LNX at this years DCC in Atlanta, Georgia on September 21-23.

    Experimenting with High Speed Wireless Networking in the 420 MHz Band, by David Bern, W2LNX

    I actually enjoyed reading these articles. I've been knee-deep in formal IEEE journals so much so that I've forgotten what plain-language is like. "I built a quarter wave antenna with a large tuna can for the ground plane." In IEEE speak, this would translate to "Using the four maxwell equations, we built a script in MATLAB to calculate the precise length of a monopole antenna with an ideal ground..." and so on.
    Sterling Coffey, N0SSC, ARRL Youth Editor, WEEE President and EE Junior
    Missouri University of Science and Technology
    Rolla, MO

  3. #13
    Join Date
    Nov 2003
    Location
    Bradenton, FL
    Posts
    44

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    Quote Originally Posted by K1DNR View Post
    Interesting, but I'm skeptical of this being a viable commercial Internet access alternative.

    It says acceptable bandwidth can easily be obtained at 70cm in a 5 to 10MHz channel. Ok. That is for a single user. I believe OFDM can accommodate multiple signals - but not a city or even small town population distributed over a few channels. One advantage to the cell concept is that it distributes users over multiple towers to minimize the contention ratio of subscribers to available channels on a given cell site.

    Similarly 802.11b works because of the limited range of the access points and the devices.

    It was stated that -97dBm is a required minimum for 1Mbps. Most urban, suburban and even most of rural American consumers now have access to Interent bandwidth measured in the 10's of Mbps from their cable TV company, or services like Verizon FiOS. Even DSL achieves better than 1Mbps in many cases. Web applications and other network applications are being developed and designed with that bandwidth in mind. Any cell phone on 3G or 4G already runs circles around that.

    -97dBm is roughly S5. Do we really expect a city full of consumer transmitters to all have an S5 signal level at a handful of "base" WiFi stations? What does it take to get an S5 signal into most 70cm FM repeaters? More than the 50-70mW of a typical home WiFi device, and gain.

    I see no provision for dealing with the RF congestion of a thousand UHF transmitters all contending for relative small slices of available UHF bandwidth -

    It just doesn't seem practical as a commercial solution.
    Agreed! Talk about a cluttered mess! You hit the nail on the head.

  4. #14

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    I think, that if we want to do this, we need to not try all this fancy "Automatic interference avoidance...". Let's just have the FCC cancel all Broadcast licenses, AM, FM and TV, and turn all that bandwith over to industry to do what they want with it to the highest bidder. THAT's the American way of throwing us all to the wolves.

    Seriously, this hunger for bandwidth is like the demand for Gambling - they keep opening Casinos, claiming there is demand. Then they whine when their 'unlimited' data plans are costing them.

    RF bandwidth is limited and should be priced accordingly. No one should be streaming radio in their car, watching TV/movies on cell phone system bandwidth, unless it costs a bunch more than it does today. Once it starts to COST to use bandwidth, then usage will drop to reasonable levels and we can stop dedicating all RF space in the USA to playing Angry Birds while walking downtown.
    This Space Intentionally Left Blank

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