[RFI] Lightsquared potential jamming of GPS

[K8RI]

On 3/10/2011 10:56 AM, Steve Sacco NN4X wrote:
> You think we have RFI problems!  The GPS industry is freaking out about
> this Lightsquared proposal.

It should be far more than the GPS industry.
Almost all transportation from air, rail, trucking, and shipping depend 
on GPS in one form or another.
The banking and financial industry uses it for highly accurate time 
stamping.

> After reading the article, check out the links at the bottom of the page
> to other goings-on about the concerns.
>
> http://www.gpsworld.com/gnss-system/gps-modernization/news/first-lightsquaredgps-working-group-meeting-held-11197

This affects far more than international flights.  Nearly all aviation 
IFR flights over the continental US, General aviation, All current cell 
phones, emergency services, car navigation, shipping within range of 
shore stations, and many things we don't even associate with GPS are 
likely to be affected.  Now days GPS affects nearly all phases of our 
lives including the national power grid and even amateur radio.

The power levels authorized to LightSquared for these ground stations is 
45 KW, not one KW in a frequency band set aside for satellite service.  
They talk about a transmitting filter, but how well do you think a 
reciver listening to a signal measured in microvolts or a fraction of a 
mircovolt would fare just running next to a *clean* carrier of 45 KW?  
Admittedly that is an over simplification, but OTOH it's pretty much the 
general idea.  It's unlikely they can do any thing to a clean signal to 
improve blocking of the GPS signals and LightSquared has already stated 
they believe it's up to the GPS industry to fix the problem.

Simulations (by Garmin) have shown these signals can block GPS receivers 
for many miles.

On top of this BTW are the jammers or personal privacy devices of PPDs 
that "intentionally jam GPS which although illegal are widely available. 
Until recently they were available on e-bay in ranges from $30 to well 
over $300 and capabilities from a few hundred feet to miles.  A Google 
search on Personal Privacy Devices turned up over 104,000 hits with them 
as cheap as $16.00. Some sites were selling  jamers for cell phones, 
WiFi, GSM, and stuff I'd never heard of.  Many of these were articles 
about the problem, but many of them were places selling the PPDs.

One of these, or likely LightSpeed could render APRS useless during 
storm chasing, not to mention the Biz Jet coming in to land IFR at the 
local airport where they are using GPS for both horizontal and vertical 
guidance.

To top it off, this is being pushed against the wishes of the Department 
of Defense, Department of Transportation, and IIRC the TSA who have been 
told they will participate in the program although I'm not sure what 
participate means unless it's "quit complaining".

73

Roger (K8RI)


> 73,
> Steve
> NN4X
>
>
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