On Mon, 19 Jul 2010 01:42:33 GMT, (patric albutat)
wrote:

So how exactly are we going to create superior charts in regions with
no GPS coverage? Or what use would these charts be to a sailor trying
to navigate a tricky coast without sat nav to give him his position?

Just where are these areas without coverage? Hint: the G in GPS stands
for Global. It's like taxes: everywhere.

Casady

On Sun, 18 Jul 2010 20:19:22 -0500, Richard Casady
wrote:

Just where are these areas without coverage? Hint: the G in GPS stands
for Global. It's like taxes: everywhere.

Apparently there is this conspiracy theory that "someone" is jamming
GPS signals near the coast of Cuba. There is plenty of evidence that
GPS normally works just fine in that area but when people run aground
it is convenient for the ego to have some alternative explanation.

Richard Casady wrote:

On Mon, 19 Jul 2010 01:42:33 GMT, (patric albutat)
wrote:

So how exactly are we going to create superior charts in regions with
no GPS coverage? Or what use would these charts be to a sailor trying
to navigate a tricky coast without sat nav to give him his position?

Just where are these areas without coverage?


http://waas.stanford.edu/~wwu/papers...itch_stu95.pdf

http://waas.stanford.edu/~wwu/papers...F/SeoIES08.pdf

http://www.agu.org/pubs/crossref/200...RS003066.shtml

http://www.fly-low.com/features02/gpsdenial.html

https://www.fbo.gov/index?s=opportun...f11c050aeb be
7682bc9ba408a&tab=core&_cview=1

http://www.aviationkb.com/Uwe/Forum....Interference-T
esting-711-reporting

Note that the published radius of jamming by the USG is 180 - 400 nm
(reported for both Maryland and China Lake) something that Wayne refuses
to acknowledge as he repeats that jamming isn't possible over a large
area.

Presumably the NOTAMS stating that jamming was occuring over a wide area
of sea off Cornwall previously posted doesn't mean anything to Wayne
because it's happening somewhere foreign.

Hint: the G in GPS stands for Global. It's like taxes: everywhere.

Then there's the World Series ... so that according to you involves
everyone in the world? It doesn't even involve a significant fraction of
the world's nations. Does Universal Studios involve the entire Universe?

(Steve Firth) wrote in news:1jlv6sr.1b9ejr91nd0q9uN%%
:

Richard Casady wrote:

On Mon, 19 Jul 2010 01:42:33 GMT, (patric albutat)
wrote:

So how exactly are we going to create superior charts in regions with
no GPS coverage? Or what use would these charts be to a sailor trying
to navigate a tricky coast without sat nav to give him his position?


I guess it had to come......No GPS, no way to fix your position...

In article ,
Richard Casady wrote:

On Mon, 19 Jul 2010 01:42:33 GMT, (patric albutat)
wrote:

So how exactly are we going to create superior charts in regions with
no GPS coverage? Or what use would these charts be to a sailor trying
to navigate a tricky coast without sat nav to give him his position?

Just where are these areas without coverage? Hint: the G in GPS stands
for Global. It's like taxes: everywhere.

Casady

Just about ANY Military Nuclear Site in the USA. Most of the FEMA
Bunkers. Most of the SAC Bases have that capability, but only test it
unless at DefCon 2 or higher. White House & Capitol Building, depending
on the immediate Threat Level. Places like that here in this country.
Overseas, Many of the National Parliament buildings, and Presidential
Palaces, and major Military installations, and places like that. Global
means Global Coverage from the Sky, not global coverage on the Ground
when local Jammers are active. This isn't Rocket Science, and many
Militaries around the world can, and do Jam the Civilian Datastreams,
within their boarders. The P-Code & Military Datastreams, are a lot more
resistant to such Jamming.

--
Bruce in alaska
add path after fast to reply

On Mon, 19 Jul 2010 11:48:28 -0800, Bruce in alaska
wrote:

Just about ANY Military Nuclear Site in the USA. Most of the FEMA
Bunkers. Most of the SAC Bases have that capability, but only test it
unless at DefCon 2 or higher. White House & Capitol Building, depending
on the immediate Threat Level. Places like that here in this country.
Overseas, Many of the National Parliament buildings, and Presidential
Palaces, and major Military installations, and places like that. Global
means Global Coverage from the Sky, not global coverage on the Ground
when local Jammers are active. This isn't Rocket Science, and many
Militaries around the world can, and do Jam the Civilian Datastreams,
within their boarders. The P-Code & Military Datastreams, are a lot more
resistant to such Jamming.

Good information. Do you have an estimate of how far offshore a local
jamming effort might extend?

NOTAM:

Oakland Center (Fremont CA) [ZOA]: April NOTAM #31 issued by Gps Notam OA [GPS]
Navigation GPS is unreliable and May BE unavailable WITHIN A 375 nautical miles
RADIUS of 393101N/1175659W LOVELOCK / LLC / VORTAC 141.25 DEGREE radial at 46.65
nautical miles, at FL400; decreasing in area with DECREASE in altitude to 290
nautical miles RADIUS at FL250; 220 nautical miles RADIUS at 10000 ft. mean sea
level, and 220 nautical miles RADIUS at 4000 ft. above ground level. effective
from April 09th, 2010 at 06:00 AM PST (1004091400) - April 09th, 2010 at 11:30
AM PST (1004091930)

On Mon, 19 Jul 2010 23:18:19 -0500, cavelamb
wrote:

NOTAM:

Oakland Center (Fremont CA) [ZOA]: April NOTAM #31 issued by Gps Notam OA [GPS]
Navigation GPS is unreliable and May BE unavailable WITHIN A 375 nautical miles
RADIUS of 393101N/1175659W LOVELOCK / LLC / VORTAC 141.25 DEGREE radial at 46.65
nautical miles, at FL400; decreasing in area with DECREASE in altitude to 290
nautical miles RADIUS at FL250; 220 nautical miles RADIUS at 10000 ft. mean sea
level, and 220 nautical miles RADIUS at 4000 ft. above ground level. effective
from April 09th, 2010 at 06:00 AM PST (1004091400) - April 09th, 2010 at 11:30
AM PST (1004091930)

Those ranges quoted are for aircraft thousands of feet above sea
level. The jamming range would be much shorter for boats, probably
10 miles or less.

Wayne.B wrote:
On Mon, 19 Jul 2010 23:18:19 -0500, cavelamb
wrote:

NOTAM:

Oakland Center (Fremont CA) [ZOA]: April NOTAM #31 issued by Gps Notam OA [GPS]
Navigation GPS is unreliable and May BE unavailable WITHIN A 375 nautical miles
RADIUS of 393101N/1175659W LOVELOCK / LLC / VORTAC 141.25 DEGREE radial at 46.65
nautical miles, at FL400; decreasing in area with DECREASE in altitude to 290
nautical miles RADIUS at FL250; 220 nautical miles RADIUS at 10000 ft. mean sea
level, and 220 nautical miles RADIUS at 4000 ft. above ground level. effective
from April 09th, 2010 at 06:00 AM PST (1004091400) - April 09th, 2010 at 11:30
AM PST (1004091930)

Those ranges quoted are for aircraft thousands of feet above sea
level. The jamming range would be much shorter for boats, probably
10 miles or less.


aSSuming it's a linear relationship, I get 202 mile radius...




--

Richard Lamb

On 7/20/2010 1:41 AM, cavelamb wrote:
Wayne.B wrote:
On Mon, 19 Jul 2010 23:18:19 -0500, cavelamb
wrote:

NOTAM:

Oakland Center (Fremont CA) [ZOA]: April NOTAM #31 issued by Gps
Notam OA [GPS]
Navigation GPS is unreliable and May BE unavailable WITHIN A 375
nautical miles RADIUS of 393101N/1175659W LOVELOCK / LLC / VORTAC
141.25 DEGREE radial at 46.65 nautical miles, at FL400; decreasing in
area with DECREASE in altitude to 290 nautical miles RADIUS at FL250;
220 nautical miles RADIUS at 10000 ft. mean sea level, and 220
nautical miles RADIUS at 4000 ft. above ground level. effective from
April 09th, 2010 at 06:00 AM PST (1004091400) - April 09th, 2010 at
11:30 AM PST (1004091930)

Those ranges quoted are for aircraft thousands of feet above sea
level. The jamming range would be much shorter for boats, probably
10 miles or less.


aSSuming it's a linear relationship, I get 202 mile radius...




Not linear: for a ground level jammer,
The line of sight estimator for distance versus height above sea level
goes something like this:
distance n.m. = 1.2 sqrt (Height ft MSL)