At 15:54 04 July 2015, jfitch wrote:
On Saturday, July 4, 2015 at 2:15:06 AM UTC-7, Tim Newport-Peace wrote:
At 03:18 04 July 2015, John Carlyle wrote:
Jon,

I flew 3 hours today, and my Butterfly vario was happy with all of the
mess=3D
ages from my Flarm (v6.03). My messages typically look like
LFLA185213GP=
S
1=3D
0 45.=3D20

I'm in PA, so maybe there's something to Matt's GPS jamming
theory.=3D20

-John, Q3

On Friday, July 3, 2015 at 11:26:00 AM UTC-4, jfitch wrote:
In the Flarm IGC file there appear to be no skipped Lat Long records
arou=3D
nd these messages. Time correlating to the Air Av IGC log, at each of
th=
e
i=3D
nstances there are no missing fixes.=3D20
=3D20
My guess is that it is a Air (Butterfly) vario thing. The Flarm NMEA
stre=3D
am must have changed to introduce some new stuff at the 6.0 change,
and
the=3D
vario is choosing to warn about things that might be better unsaid.
But
I
=3D
was trying to get more info on the PowerFlarm first.


If you look at the GPS Altitude trace in SeeYou, this Should go to zero
when there are no valid GPS Positions.

Yes it does. Pressure altitude is still present, and perfectly tracks the
T=
riadis log. Further dissecting the B records, for those that are bad, the
f=
ix is indicated as "V" (2D), fix accuracy as "999", and satellites
tracked
=
as "00". The latitude and longitude are repeats of the last valid fix,
as
=
required by the IGC spec.=20

The conclusion is that the voice warnings are real, and the PowerFlarm
GPS
=
has gone Tango Uniform. The fact that it works in approximately the
second
=
half of the flight makes me suspect heat susceptibility (ground temps in
th=
e 90's F, vs. 50 at altitude). I will try playing with the antenna
location=
(but it is the same as last year when it worked fine).


Don't know how relevant this is, but on a UK Newsgroup it was written:

At 14:13 01 July 2015, John Firth wrote:
At 15:57 29 June 2015, Guy Corbett wrote:
Late morning last Wednesday (24th) launching was delayed in the
Shenington
regionals because all competitors lost GPS coverage. 0 satellites were
being tracked, after a couple of minutes coverage returned. Was this a
local effect or did it happen elsewhere? The organisers found no
relevant
NOTAMS.
Don't blame Hilary.

Has no one heard of solar storms? The ejected electrons
and protons hit the tenous outer atmosphere, causing
intense ionisation ( lots of electrons) and block
radio signals from space.
there were two intense solar flares that week and ai suspect
for a few minutes the lecetron density was such that
GPS signals were blocked.

http://www.swpc.noaa.gov/

Soaring needs the sun.