Re: [time-nuts] lightsquared test in las vegas
This is kind of in reference to other LightSquared articles that all seem to make mention of, "LightSquared's proposal for a network
of 40,000 ground transmitters..."
These 40k ground transmitters to be installed... Are they just going to be additional antennas on existing cell towers, or is
LightSquared planning to construct their own towers in new locations?
Reason I say... Cell towers are located for maximum coverage and the most dense population. Likewise, when traveling between cities
they stick them close to the interstates so people can have reception while traveling. A blind man should be able to see that
problem.
<rant>I guess the rest of the world will be able to enjoy GPS, while the US pays for it (but can't use it).... But hey, watching
people do stupid things on youtube is infinitely more necessary for the US economy than a critical navigation system deployed in
countless cars, boats, planes, and anything else that moves....
This should have been killed off a long time ago, and the frequency spectrum stripped away from LightSquared just for the mere
mention of doing something as stupid as they are trying to do...</rant>
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
Jason Rabel wrote:
This is kind of in reference to other LightSquared articles that all seem to make
mention of, "LightSquared's proposal for a network of 40,000 ground
transmitters..."
These 40k ground transmitters to be installed... Are they just going to be
additional antennas on existing cell towers, or is LightSquared planning to
construct their own towers in new locations?
Reason I say... Cell towers are located for maximum coverage and the most dense
population. Likewise, when traveling between cities they stick them close to the
interstates so people can have reception while traveling. A blind man should be
able to see that problem.
<rant>I guess the rest of the world will be able to enjoy GPS, while the US pays
for it (but can't use it).... But hey, watching people do stupid things on youtube
is infinitely more necessary for the US economy than a critical navigation system
deployed in countless cars, boats, planes, and anything else that moves....
This should have been killed off a long time ago, and the frequency spectrum
stripped away from LightSquared just for the mere mention of doing something as
stupid as they are trying to do...</rant>
Perhaps not in the abstract, but on-orbit power is severely limited, and
you can't get more RF watts out of a transmitter than you put in as DC.
Can you imagine the uproar if every GPS bird had a 10 KW transmitter on
board, powered bu a nuclear reactor?
The low received power is a direct consequence of engineering of satellites.
-John
================
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
Hi Jason:
For more than a decade the best internet connection I could get was
2-way satellite. The major problem with that is the ping time which
approaches one second and no amount of technology will change it one
iota (i.e. it's determined by two round trips up and back to the
satellite and the speed of light). Now that I've got DSL the ping time
is in the 25 ms area, see: http://www.prc68.com/I/attDSL.shtml
With DSL I can now get Netflix streaming video. This means watching
movies, some in HD. Crackle and others offer a similar service. This
takes much more bandwidth than YouTube. Note that YouTube has a 10
minute time limit and used to have a file size limit, but the file size
limit has been removed to encourage HD and/or 3D format uploads. I've
heard the movies over the internet are driving internet bandwidth.
Have Fun,
Brooke Clarke
http://www.PRC68.com
Jason Rabel wrote:
This is kind of in reference to other LightSquared articles that all seem to make mention of, "LightSquared's proposal for a network
of 40,000 ground transmitters..."
These 40k ground transmitters to be installed... Are they just going to be additional antennas on existing cell towers, or is
LightSquared planning to construct their own towers in new locations?
Reason I say... Cell towers are located for maximum coverage and the most dense population. Likewise, when traveling between cities
they stick them close to the interstates so people can have reception while traveling. A blind man should be able to see that
problem.
<rant>I guess the rest of the world will be able to enjoy GPS, while the US pays for it (but can't use it).... But hey, watching
people do stupid things on youtube is infinitely more necessary for the US economy than a critical navigation system deployed in
countless cars, boats, planes, and anything else that moves....
This should have been killed off a long time ago, and the frequency spectrum stripped away from LightSquared just for the mere
mention of doing something as stupid as they are trying to do...</rant>
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and follow the instructions there.
Hi John:
It's my understanding the the GPS system was designed by the military so
that the received signal is below the thermal noise. That means that if
you look for it with a spectrum analyzer you will see noise. It wasn't
untill the KAL007 shoot down that the goverment disclosed it's existence
to prevent a similar thing from happening. The new GPS L5 "Safety of
Life" signal is to make aviation safer. So it appears that the focus
has changed from military to aviation.
http://en.wikipedia.org/wiki/Korean_Air_Lines_Flight_007#Aftermath
http://www.prc68.com/I/DAGR.shtml#GPSs
Have Fun,
Brooke Clarke
http://www.PRC68.com
J. Forster wrote:
Perhaps not in the abstract, but on-orbit power is severely limited, and
you can't get more RF watts out of a transmitter than you put in as DC.
Can you imagine the uproar if every GPS bird had a 10 KW transmitter on
board, powered bu a nuclear reactor?
The low received power is a direct consequence of engineering of satellites.
-John
================
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
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To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Hi Brooke,
Could well be, but I know the system was severely constrained by satellite
design considerations. 30+ years ago, high power was simply not available
on orbit for long periods of time. The only real option is solar cells,
then as now.
-John
==============
Hi John:
It's my understanding the the GPS system was designed by the military so
that the received signal is below the thermal noise. That means that if
you look for it with a spectrum analyzer you will see noise. It wasn't
untill the KAL007 shoot down that the goverment disclosed it's existence
to prevent a similar thing from happening. The new GPS L5 "Safety of
Life" signal is to make aviation safer. So it appears that the focus
has changed from military to aviation.
http://en.wikipedia.org/wiki/Korean_Air_Lines_Flight_007#Aftermath
http://www.prc68.com/I/DAGR.shtml#GPSs
Have Fun,
Brooke Clarke
http://www.PRC68.com
J. Forster wrote:
Perhaps not in the abstract, but on-orbit power is severely limited, and
you can't get more RF watts out of a transmitter than you put in as DC.
Can you imagine the uproar if every GPS bird had a 10 KW transmitter on
board, powered bu a nuclear reactor?
The low received power is a direct consequence of engineering of
satellites.
-John
================
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
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Hi
Ummm, errr ... not so much.
KAL007 went down September 7th 1983. NIST was publishing papers on two way
time transfer in 1980:
http://tf.nist.gov/general/pdf/192.pdf
Much of the early GPS timing and design work was made quite public in
various FCS papers in the 1970's.
Bob
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Brooke Clarke
Sent: Thursday, June 09, 2011 1:28 PM
To: jfor@quik.com; Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] lightsquared test in las vegas
Hi John:
It's my understanding the the GPS system was designed by the military so
that the received signal is below the thermal noise. That means that if
you look for it with a spectrum analyzer you will see noise. It wasn't
untill the KAL007 shoot down that the goverment disclosed it's existence
to prevent a similar thing from happening. The new GPS L5 "Safety of
Life" signal is to make aviation safer. So it appears that the focus
has changed from military to aviation.
http://en.wikipedia.org/wiki/Korean_Air_Lines_Flight_007#Aftermath
http://www.prc68.com/I/DAGR.shtml#GPSs
Have Fun,
Brooke Clarke
http://www.PRC68.com
J. Forster wrote:
Perhaps not in the abstract, but on-orbit power is severely limited, and
you can't get more RF watts out of a transmitter than you put in as DC.
Can you imagine the uproar if every GPS bird had a 10 KW transmitter on
board, powered bu a nuclear reactor?
The low received power is a direct consequence of engineering of
satellites.
-John
================
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
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
and follow the instructions there.
time-nuts mailing list -- time-nuts@febo.com
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and follow the instructions there.