[time-nuts] GPS interference and history...

Burt I. Weiner biwa at att.net
Thu Jun 9 17:29:14 UTC 2011

For many years the FCC has not allowed FM broadcast stations within 
certain distances of each other where a 10.7 MHz frequency difference 
existed.  Not exactly the same thing, but did show an understanding 
of what can go wrong as a result of good receiver front end 
selectivity.  In AM and FM broadcasting there has also been required 
distances between 1st and 2nd adjacent channels, only partially 
because of overload issues but more so because of occupied bandwidth 
and overlapping.  I'm not sure how much more it would cost to build 
GPS receivers with better front ends, but I'm sure it would've priced 
GPS devices out of the hands of many consumer level users.  The FCC 
under the direction of Congress has made (allowed) some pretty stupid 
moves in the past bunch of years.  In my opinion, the FCC has 
forgotten what their purpose is, and being run by attorneys has made 
the situation that much worse as there are very few attorneys that 
understand the un-revocable physics of the electromagnetic spectrum.

Burt, K6OQK

At 10:07 AM 6/9/2011, time-nuts-request at febo.com wrote

>On the other hand, what can be said about the wisdom of engineers that
>designed a product that cannot withstand any interference from adjoining
>spectrum holders?  It has been known for at least the last 6 years that
>LightSquared's predecessor was going to occupy that spectrum with a land
>based system.
>Does the GPS world really have much to say about the interference if
>LightSquared keeps their transmitters clean and out of the GPS spectrum?
>-Chuck Harris

Burt I. Weiner Associates
Broadcast Technical Services
Glendale, California  U.S.A.
biwa at att.net

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