Re: [Discuss-gnuradio] Salon article -- off topic

[David Bengtson]

This was an interesting read, but I'm concerned about changing
spectrum policy based on a bunch of powerpoint slides saying that it
is possible to make a smart radio. 

Putting my receiver engineer hat on, my mind boggles at the receiver
linearity specifications needed to receive a femto watt 802.11
transmission while not being pounded into a quivering blob by a
megawatt FM radio station. 

The software to make this all work is conceptually feasible, although
it isn't written. The RF front ends to do this will require some major
technology breakthroughs. 

Cost will also be a concern, making this at a price that is
affordable. 

I don't see anything here that is impossible, but certainly there is a
ton of work to be done before it's feasible. As far as timeframe, I'm
thinking 10 to 15 years before this is feasible. 

On the other hand, given the speed of government, perhaps it's time to
start kicking the tires on open spectrum. 


Dave



On Wed, 12 Mar 2003 17:40:42 -0800, you wrote:

>http://www.salon.com/tech/feature/2003/03/12/spectrum/index2.html
>
>Referenced on slashdot...
>
>Eric -- I haven't been here very long, but my assumption about this code to
>demod two FM stations at once is NOT an example of how you can demod two FM
>stations "on a single frequency" as stated by David Weinberger in this Salon
>article.
>
>With that, I'm having trouble understanding David Reed's point here.
>Bandwidth is limited to the energy you can stuff into a photon, and in that
>respect, is limitless... and I agree that "interference" can be the cause of
>a crummy receiver (poor linearity, image rejection, etc). But this fellow is
>talking about a situation where everyone can be transferring bazillions of
>bits to everyone else on the planet, and as long as "the system" was set up
>right, everything would be fine. 
>
>Mr. Claude Shannon has something to say about this, and to my knowledge, his
>has only been cheated by using spatial separation (tricks like beam-forming
>antennas and sectorization and such).
>
>http://cm.bell-labs.com/cm/ms/what/shannonday/shannon1948.pdf
>
>If someone on the s/w side understands something I don't about this, please
>email me directly, since this is more than a little off-topic.
>
>Brian Whitaker
>
>
>
>_______________________________________________
>Discuss-gnuradio mailing list
>address@hidden
>http://mail.gnu.org/mailman/listinfo/discuss-gnuradio