"Flarm, no GPS"

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=
ages from my Flarm (v6.03). My messages typically look like LFLA185213GPS
1=
0 45.=20

I'm in PA, so maybe there's something to Matt's GPS jamming theory.=20

-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=
nd these messages. Time correlating to the Air Av IGC log, at each of the
i=
nstances there are no missing fixes.=20
=20
My guess is that it is a Air (Butterfly) vario thing. The Flarm NMEA
stre=
am must have changed to introduce some new stuff at the 6.0 change, and
the=
vario is choosing to warn about things that might be better unsaid. But
I
=
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.

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=
ages from my Flarm (v6.03). My messages typically look like LFLA185213GPS
1=
0 45.=20

I'm in PA, so maybe there's something to Matt's GPS jamming theory.=20

-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=
nd these messages. Time correlating to the Air Av IGC log, at each of the
i=
nstances there are no missing fixes.=20
=20
My guess is that it is a Air (Butterfly) vario thing. The Flarm NMEA
stre=
am must have changed to introduce some new stuff at the 6.0 change, and
the=
vario is choosing to warn about things that might be better unsaid. But
I
=
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 Triadis log. Further dissecting the B records, for those that are bad, the fix 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.

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 the 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).

Further confirmation of my long held belief that anything over 80 degrees F should be illegal... grin

-John, Q3

On Saturday, July 4, 2015 at 11:54:16 AM UTC-4, jfitch wrote:
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 the 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).

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.

On Saturday, July 4, 2015 at 10:00:22 AM UTC-7, Tim Newport-Peace wrote:
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.


It is possible the Flarm GPS is simply weaker than every other one, and if the S/N ratio goes down due to solar flares or whatever, the Flarm fails first. I have 4 other GPS receivers in the glider (iPhone 5s, iPhone 6+, inReach, Air Vario), none of them seemed to have any trouble while the Flarm did.

I have also talked to more that a few Flarm owners who think that there are many more dropouts this year compared to last year. Which makes me wonder all the more about what was done in the 6xx firmware.

I was getting a "Flarm Fault 3" message
from my Air Glide
vario. The manufacturer advised me to
install the latest software version (which
seems not to have been announced)
which was issued for compatibility with
the new PowerFlarm release.

Fixed that problem for me.

On Saturday, July 4, 2015 at 4:15:04 PM UTC-7, George Haeh wrote:
I was getting a "Flarm Fault 3" message
from my Air Glide
vario. The manufacturer advised me to
install the latest software version (which
seems not to have been announced)
which was issued for compatibility with
the new PowerFlarm release.

Fixed that problem for me.

The "Flarm Fault 3" message is due to the Flarm serial link being unresponsive, which could be due to several reasons (and the Air Vario in prior firmware revisions created some of these reasons). However I am running the latest Air Vario firmware (labeled 2242 but reports as 2240). This is a different problem, and the source appears to be the Flarm.

On Thursday, July 2, 2015 at 10:12:49 PM UTC-7, jfitch wrote:
I am getting this bitching Betty alarm every so often. It may do it for a minute or so, then goes away, then comes again.

Looking at the Flarm IGC file, there are comment lines that look like this:

LFLA213757GPS 7 45

Which I believe represents GPS status (7 satellites?)

Then I get some that look like this:

LFLA213857GPS 0 0

No satellites? The B field time stamps show a lat and long 4 seconds before and 4 seconds after. In the flight today I got 14 of these and about that many warnings (I didn't count the warnings).

This didn't happen last year, started coincident with the 6.0.2 firmware "upgrade".

Can anyone shed any light on this? Can't find any spec from Flarm that describes it.

I have now written an XL parser for the Flarm IGC file, which counts the instances of dropped fixes. I found no dropped fixes at all from flights in 2013. I found dropped fixes in one flight in 2014, 56 dropped on one particular flight, none in any others. I have now 3 flights in 2015 with the new firmware. 1st flight shows 19 dropped fixes, 2nd flight 373 dropped fixes, 3rd flight 882 (and all fairly short flights too). Not an encouraging trend.

The reason I am now aware of it, is that the new Flarm firmware announces bad fixes with the Lxxxxxx GPS 0 0 comment line, and the Air Vario announces it to me with a voice warning. Didn't do that before.

I had issues right after I upgraded my brick a couple of months ago. Turned out to be a loose GPS cable connection to the brick as the GPS antenna does not screw on just pushes on. I pushed it back on and hasn't had a problem since.

On Saturday, July 4, 2015 at 8:17:08 PM UTC-7, wrote:
I had issues right after I upgraded my brick a couple of months ago. Turned out to be a loose GPS cable connection to the brick as the GPS antenna does not screw on just pushes on. I pushed it back on and hasn't had a problem since.

I tried pulling and reseating the connector. I wonder if a more efficient antenna would work better on the Flarm. Is anyone using a larger patch antenna with it?