Words of Advice:

"If Something Seems To Be Too Good To Be True, It's Best To Shoot It, Just In Case." -- Fiona Glenanne

"Flying the Airplane is More Important than Radioing Your Plight to a Person on the Ground
Who is Incapable of Understanding or Doing Anything About It." -- Unknown

“Never argue with stupid people, they will drag you down to their level
and then beat you with experience.” -- Mark Twain

"John Wick didn't kill all those people because they broke his toaster." -MickAK

"Everything is easy if somebody else is the one doing it." -- Me

"What the hell is an `Aluminum Falcon'?" -- Emperor Palpatine

"Eck!" -- George the Cat

Thursday, April 5, 2012

SSTs and LightSquared

LightSquared is likely to file bankruptcy. The CEO says it will be voluntary. I have little doubt that the creditors will press for a liquidation. Frankly, I feel that LightSquared can't go away fast enough. And they're not the first company to jump on a part of the EM spectrum, only to discover that they couldn't use it.

NASA thinks that it will soon be possible to make a small business jet that can operate supersonically over land.
NASA is claiming a breakthrough in the design of supersonic aircraft, with wind-tunnel tests proving it is possible to design configurations that combine low sonic boom with low cruise drag, characteristics once thought to be mutually exclusive.
As noted in the article, one of the issues is the size of the aircraft-- bigger airplanes have a louder sonic boom. So they may be able to do this with a bizjet. And they'll sell, just like the Citation X has sold.


Vannevar said...

LightSquared has (unintentionally) performed a valuable public service, demonstrating the fragility of the GPS basket we're about to put all our air navigation eggs into (wow - is that a timely Easter analogy or what?).

There's no doubt they were trying to leverage what they thought was an undervalued part of the public spectrum, but perhaps some good will come from their hubris if we can ever get past our own.

harumph, harumph.

Nangleator said...

Is the NASA jet incapable of getting a sonic boom to the ground because you can't go supersonic below a certain altitude?

Or will the 0.1% be busting up all our glass and giddily paying the fines?

Comrade Misfit said...

It's a matter of a better understanding of fluid dynamics, thanks both to better programs and much more powerful computers. Smaller airplanes produce a smaller sonic boom and between that and the tweaks to airframe design, a small airplane should be able to go low supersonic without much of a boom.

And chances are that it'll be the 0.01% who can afford the $100-million plus for one of those puppies.

Eck! said...

The problem of Lightsquared is deeper than their plan. It reflects on the rather antiquated usage of Radio frequency allocations. AS technology progresses many technologies that tended to stay lower in frequency have become so entrenched as to be for practical reasons (costs)
unmovable. At the other end we had the cutting edge high tech going where they though would be empty space that has become highly
congested or allocated as "quiet or good neighbor regions". Again those satellite based systems are most difficult as they cannot move
until we acquire the ability to go fetch and refurbish those birds. Even then the ground systems are not easily moved as shear numbers and
costs are real and practical factors.

It's a bad situation as frequencies are a finite resource, and the only mitigation is as you go up in frequency beyond VHF the range
is essentially self limiting (line of sight), or limiting the power, untill you add the ingredient of satellites who at any time see
half the earth.

In the end there is no coherent unified plan for the RF/Electromagnetic infrastructure nor any for avoiding interference from those systems
like TVs and computers that both use RF and by their nature generate RF interference. Interference is the EM equivalent of pollution and
many parts of the spectrum are quite polluted.


Vannevar said...

Quite right, Eck!

BadTux said...

And it doesn't help that huge chunks of spectrum are allocated for FM audio transmissions (e.g. the air bands and public safety bands), which use spectrum spectacularly inefficiently compared to modern spread-spectrum cellular technologies which are getting darn close to the Shannon limit. You can send more voice phone calls over a single 16khz chunk of the 800mhz band in a day than the entire air band plus public safety band combined transmit in an entire day. Yet they have hundreds of megahertz of spectrum dedicated to the public safety bands and air bands, spectrum that could carry a million times more voice (and not) data each day than it currently does if the FM audio transceivers were obsoleted and replaced with a more efficient technology.

One advantage of the newer technologies is that because of their frequency-hopping spread spectrum nature, you can deal with interference much more easily. The algorithms basically route around it. The problem with the GPS satellites is that they're an *old* technology, relatively speaking, and very low powered due to the fact that it costs a lot to hoist big solar panels into orbit. Furthermore, there are so many millions of GPS receivers out there on the planet that changing the protocol they use would be cost-prohibitive. There's maybe a million public safety radios total on the planet. There's probably close to a billion GPS-enabled devices on the planet -- everything from phones to digital cameras have GPS in them nowadays. If you're looking for spectrum, looking at the FM voice bands is the best place to look, because nowadays that's just a few million radios, not literally a *billion* of them...

- Badtux the Hammy Penguin