No subject

[Chip Fetrow]

This DOES happen all the time.  Since the circle tends to have zero
radius at ground level, we don't tend to ever notice it.  This is one
of the largest I have seen -- I was going to write "in some time," but
I believe the correct reference is, EVER.

The tests tend to be centered over military bases, but some of these
NOTAMs are outages caused by satellite geometry.

I used to subscribe to a mailing list that sent all of them to me.  It
was interesting for a while, but then less so.  Then, they changed the
list, and I found it difficult to follow it, so I just gave up.

As for this one, 325 NM at FL 250 means nothing to me.  If I am at FL
250 someone else is piloting the ship.

260 NM at 10,000 feet MIGHT mean something to me, but pretty doubtful.

215 NM at 4,000 feet is likely an issue, but I have never used GPS for
my primary navigation anyway, so it doesn't matter to me much.

Still, this is likely the biggest "hole" I have ever seen.

--chip

On Jan 21, 2011, at 6:59 PM, tacos-request at rf.org wrote:

> Message: 2
> Date: Fri, 21 Jan 2011 13:15:33 -0600 (CST)
> From: Robert Stratton <bob at stratton.net>
>
> They do those all of the time. Flying around here, I would usually
> encounter NOTAMs for them doing the same thing at Pax River, but
> over a smaller radius that this one at St. Simons Island. It's
> annoying. Obviously this is some interpretation of "critical
> infrastructure" with which I'm previously unaccustomed.
>
> --Bob S.
>
> ----- Original Message -----
>> This seems strange:
>>
>> https://www.faasafety.gov/files/notices/2011/Jan/GPS_Flight_Advisory_CSFTL11-01_Rel.pdf
>>
>> "The Department of Defense will conduct GPS tests on January
>> 20th through February 22nd 2011. During testing, the GPS signal
>> may be unreliable or unavailable."
>>
>> "During testing, GPS will be unreliable and may be unavailable
>> with in a circle with a radius of 370NM and centered a
>> t 304906N/0802811W or the location known as 105.25 degrees
>> and 52.1 NM from the SSI VOR at FL400; decreasing in area with
>> a decrease in altitude to a circle with a radius of 325NM at FL250;
>> a circle with a radius of 260NM at 10,000FT MSL and a circle with
>> a radius of 215NM at 4,000FT AGL."
>> (see the PDF for the area that will be impacted, it's off the coast
>> of
>> GA/FL
>>
>> Doug