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Sharing the Airwaves: Spread-Spectrum Broadcasting
NaDrew writes "From the SFGate: Hal Plotkin writes about how Spread-Spectrum broadcasting technology could revolutionize the way we listen to the radio, and make it incredibly easy for neo-broadcasters to start their own services. Sadly, he writes, the "often technically inept U.S. Congress has complicated the situation in recent years by shortsightedly instructing the FCC to sell or lease additional bands of spectrum that had been reserved for other uses." Not to mention "the media conglomerates that own most of the nation's TV and radio stations have a vested interest in the status quo and won't easily give up their hammerlock on what, in the end, are public airwaves." A fascinating article that also includes some history of Spread-Spectrum technology (did you know it was patented by Hedy Lamarr?)." A good primer to spread spectrum if you're new to the issue.
Sure if you are not tuned in, it looks just like noise.
But if people are not careful what will happen is the noise floor is raised higher and higher till it drowns out signals.
Yah that isn't close to happening yet, but the way it's being hyped as if everyone and anyone can broadcast at the same time, it might happen sooner than expected.
Not true. The more peopel share spread spectrum areas, the worse the overall bit-error rate becomes. It's not a hard limit like in AM radio where you can ONLY divide the spectrum into a few chunks. But it cannot expand forever. Every spread spectrum transmission reduces the fidelity of every other spread specturm transmission in that range. The other transmitters just look liek noise sources.
Um. Radio is light is electromagnetic radiation. But radio has a benefit, because it is not absorbed by air. Why? Because it's long-wavelength. Basically any gaseous atmosphere is going to be transparent to radio waves, so they are probably using that - probably a liquid environment will also be transparent to it.
You're also wrong that any form of EM radiation travels well in space - dust really sucks, and it preferentially absorbs higher wavelengths (because the dust can absorb them). Radio travels well in space, light does not.
Besides, SETI is looking at an 'intelligent' portion of the spectrum (I believe... they may have switched) - the 21 cm line of hydrogen. We can't look at any large portion of the spectrum - that's really friggin' difficult. So we assume that if they're trying to contact us, they're using an intelligent wavelength.
SETI isn't looking for stray communications, in any case. They're looking for a signal intended for us to notice. If SETI fails, that doesn't mean that there isn't anything out there - it simply means they aren't trying to contact us in the way we think they are, OR they aren't trying to contact us at all.
Annual regulatory fee for an FM stations (depends on the class of station and the population of your city of license):
6. FM Classes A, B1 and C3
1,000,000 population $3,750
7. FM Classes B, C, C1 and C2
1,000,000 population $4,550
The fee that must accompany an application for a construction permit:
$3385
Now, we've just scratched the surface.
First, we have to find a frequency. Let's ask a consulting engineer to find us one: $450.
OK, but we have to have the table of allotments amended to make this frequency available in the city we want it to be in... again, get on the horn to the consulting engineer, and send him $1900 to do the petition for rulemaking.
Now, we have our frequency, it's alloted to our town. Time to file an application for a construction permit... $4000 to the consulting engineer, $3385 to the FCC.
We've spent $9735 - almost $10,000 - and we still aren't sure we'll even get a permit.
Some time passes, and assuming there are no amendments to our application (which will cost us more), we get our construction permit in the mail.
We now have 18 months to build our station and apply for a license - the construction permit just grants authority to build the station, test it and operate it until the license is applied for and granted.
The costs really start to add up now... tower, tower installation (you're not actually going to go out to the tower site and haul tower sections up by hand are you?)... antenna... transmission line... transmitter... unless our studio will be at the transmitter site, we have to buy a microwave unit to send the signal from our studio to the transmitter... then we have to have a studio, with control console, CD players, etc... oops, don't forget the audio processor and stereo generator...
Building the station actually costs a lot more than operating it... or it can, unless you are very frugal and buy a lot of used equipment!
The ongoing costs that any business has include rent, power, insurance, payroll, business license.
Then you get to pay ASCAP, BMI and SESAC their fees - and they all have an annual minimum, even if you're losing money.
Fortunately, you don't have to pay the RIAA... the only bright spot...
Of course, every year we get to pay the regulatory fee listed above.
Yes, operating a music FM can be costly - but with today's computers and software, and if you don't actually make money the ASCAP/BMI/SESAC fees aren't that much, you can keep costs to less than a lot of other businesses.