[Boatanchors] LightSquared

[Robert Nickels]

On 10/9/2012 8:00 AM, J. Forster wrote:
> No practical, realizable filter has the kind of reaponse needed to
> separate the two, especially where the LightSquared is 60 to 120 dB
> stronger. Furthermore, a GPS receiver cannot tolerate much insertion loss.

Correct.    I recall seeing some test data (submitted by Lightsquared, 
of course) that showed how with sufficient added filtering the 
avionics-grade GPS units could be made to tolerate the interference from 
their base stations.    This was immediately challenged by Garmin and 
the rest of the industry experts - and of course the FCC stood around 
twiddling its thumbs waiting for the politicans to tell it what to 
think.    Even Lightsquared admitted this filtering was expensive but 
that wasn't their problem. (Ironically, using the same logic hams have 
used for years when our transmitters operating in our authorized bands 
resulted in interference to poorly-designed TV sets!)

However we know that avionics-grade GPS units are much different 
critters than the little personal and navi units that have been sold by 
the millions.   As John's last comment suggests, it is impractical to 
design filter that is both effective and affordable. Any ham is familiar 
with the need for additional states of amplification after a filter is 
added to an amplifier circuit, and the installed base of millions of 
consumer GPS units, which are not only "nice to have" but the foundation 
of new industries worth billions of dollars such as vehicle tracking and 
logistics, telematics, and precision agriculture, would be rendered 
partially useless if Lightsquared had been allowed to go forward.

Quit worrying about them tearing up air navigation - it won't be allowed 
to happen, now that Lightsquared and their federal government enablers 
have been exposed.   But as radio hobbyists, we have to ask how this 
situation ever happened in the first place? Where was the FCC and what 
were they thinking?  Would you hire even an entry-level engineer who 
couldn't realize the potential for interference in this situation?   
(Evidently "we" have hired a whole bunch of 'em, in Washington DC...)

Gov. Rick Perry had a brain freeze when it came to naming all the 
federal agencies he'd like to shut down, but if they can't protect the 
public interest any better than this, then the FCC should be added to 
the list.

73, Bob W9RAN