FLARM - No GPS

It worked fine last time I flew but today, it was stuck on the startup
screen with 0 Satellites showing. I cycled the power a couple of times
with no effect. Both my ClearNav vario and my Dell Streak were both
receiving good GPS locks. The Streak reported 8 satellites.

The PF Portable had been stuck on my glare shield using Dual Lok
fasteners but, a few days ago I fabricated an aluminum plate to bolt the
portable to and then screw the plate to the glare shield. That should
make no difference, but I thought I would tell all.

Being new to this, I have no idea where or how to look for faults. The
PF receives switched power from the DC bus. It has 3 antennae hooked to
it, and its serial port is connected to one of the inputs of a
K6BT-Mux. The other input of the Mux is connected to the serial output
of the CN vario. The Bluetooth radio transmits to the Dell Streak
running XCSoar. On the Streak, I can monitor the interface traffic out
of the Mux. I saw sentences from the Flarm and the ClearNav vario. The
data stream from the CNv had good GPS information and the $PF sentences
appeared to have zeros instead of position data. That would agree with
the startup screen.

It's my understanding that, absent a good GPS signal of its own, the PF
portable should use the GPS data from the vario.

Can anyone offer any advice?
--
Dan, 5J

On Wednesday, November 23, 2016 at 8:08:52 PM UTC-5, Dan Marotta wrote:
It worked fine last time I flew but today, it was stuck on the startup
screen with 0 Satellites showing. I cycled the power a couple of times
with no effect. Both my ClearNav vario and my Dell Streak were both
receiving good GPS locks. The Streak reported 8 satellites.

The PF Portable had been stuck on my glare shield using Dual Lok
fasteners but, a few days ago I fabricated an aluminum plate to bolt the
portable to and then screw the plate to the glare shield. That should
make no difference, but I thought I would tell all.

Being new to this, I have no idea where or how to look for faults. The
PF receives switched power from the DC bus. It has 3 antennae hooked to
it, and its serial port is connected to one of the inputs of a
K6BT-Mux. The other input of the Mux is connected to the serial output
of the CN vario. The Bluetooth radio transmits to the Dell Streak
running XCSoar. On the Streak, I can monitor the interface traffic out
of the Mux. I saw sentences from the Flarm and the ClearNav vario. The
data stream from the CNv had good GPS information and the $PF sentences
appeared to have zeros instead of position data. That would agree with
the startup screen.

It's my understanding that, absent a good GPS signal of its own, the PF
portable should use the GPS data from the vario.

Can anyone offer any advice?
--
Dan, 5J

I would try your Portable with a known working PowerFLARM GPS antenna - I have seen one bad antenna which we tracked down this way.

Have you redone the PowerFLARM firmware within 365 days? "From the March 2015 Update, every FLARM device needs to be updated with the latest firmware version at least once per year (rolling 365 days)." - from the FLARM.com website.

If you can get a .igc file out of it, in the header it says what type of gps it is, HFGPSType: (usually a 16-channel LEA-6A or NEO-6Q GPS receiver by u-blox of Switzerland). If the type is missing, likely a gps problem.

I would be very surprised/shocked if it accepted any external GPS signals from the vario, since it can be an IGC Flight Recorder (with the proper licencing)...

Dan
2D

Thanks Dan,

Since my PF Portable appears not to have the IGC license (by looking at
the spreadsheet file), I have never seen the need to download the igc
files - I get that from the ClearNav. I downloaded the igc files
yesterday but, of course, the SD card is at the airport. There was no
igc file generated for yesterday's flight due, I suppose, to no GPS.

I updated the firmware last month when I acquired the unit and it worked
fine until yesterday. I had planned to reinstall the current firmware
to see if that made any difference. I'll also look at my last generated
igc file and see what it says about GPS.

I don't know if there are any external GPS antennae on the field, but I
can check around. A couple of weeks ago, a friend (Renny) drove around
the airport with his portable in his car and each of our units detected
and displayed the other.

Dan
5J

On 11/23/2016 8:18 PM, Dan Daly wrote:
On Wednesday, November 23, 2016 at 8:08:52 PM UTC-5, Dan Marotta wrote:
It worked fine last time I flew but today, it was stuck on the startup
screen with 0 Satellites showing. I cycled the power a couple of times
with no effect. Both my ClearNav vario and my Dell Streak were both
receiving good GPS locks. The Streak reported 8 satellites.

The PF Portable had been stuck on my glare shield using Dual Lok
fasteners but, a few days ago I fabricated an aluminum plate to bolt the
portable to and then screw the plate to the glare shield. That should
make no difference, but I thought I would tell all.

Being new to this, I have no idea where or how to look for faults. The
PF receives switched power from the DC bus. It has 3 antennae hooked to
it, and its serial port is connected to one of the inputs of a
K6BT-Mux. The other input of the Mux is connected to the serial output
of the CN vario. The Bluetooth radio transmits to the Dell Streak
running XCSoar. On the Streak, I can monitor the interface traffic out
of the Mux. I saw sentences from the Flarm and the ClearNav vario. The
data stream from the CNv had good GPS information and the $PF sentences
appeared to have zeros instead of position data. That would agree with
the startup screen.

It's my understanding that, absent a good GPS signal of its own, the PF
portable should use the GPS data from the vario.

Can anyone offer any advice?
--
Dan, 5J
I would try your Portable with a known working PowerFLARM GPS antenna - I have seen one bad antenna which we tracked down this way.

Have you redone the PowerFLARM firmware within 365 days? "From the March 2015 Update, every FLARM device needs to be updated with the latest firmware version at least once per year (rolling 365 days)." - from the FLARM.com website.

If you can get a .igc file out of it, in the header it says what type of gps it is, HFGPSType: (usually a 16-channel LEA-6A or NEO-6Q GPS receiver by u-blox of Switzerland). If the type is missing, likely a gps problem.

I would be very surprised/shocked if it accepted any external GPS signals from the vario, since it can be an IGC Flight Recorder (with the proper licencing)...

Dan
2D

--
Dan, 5J

Are you using multiple GPS antennas? They can influence each other when in close proximity.

On Thu, 24 Nov 2016 09:57:14 -0700, Dan Marotta wrote:

Thanks Dan,

Since my PF Portable appears not to have the IGC license (by looking at
the spreadsheet file), I have never seen the need to download the igc
files - I get that from the ClearNav. I downloaded the igc files
yesterday but, of course, the SD card is at the airport. There was no
igc file generated for yesterday's flight due, I suppose, to no GPS.

FLARM will write IGC files regardless of whether you have an ICG license
and software module or not. I assume PF is the same. The only thing that
IGC module adds is the ability to write a valid G record at the end of a
the log file and you only need that if you intend to submit flight logs
to a scoring system.

You can read the logfile on your PC with anything that can show the
content of a normal text file.

The other thing you may want to do is to submit your log files to the
FLARM range analysed (on their website) to see what detection range
you're getting, but this does not require the IGC module to be installed.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

I have two GPS antennae, one for the Dynon EFIS and one for the ClearNav
vario. They are on opposite sides of the Stemme's panel, about 2 feet
apart. There is no external antenna for the PF Portable. It worked
just fine on all flights previous to the one yesterday. I think my
ADS-B antenna is closer to the PF Portable unit now than it was before,
maybe 2 inches. Might that be the cause?

On 11/24/2016 11:46 AM, wrote:
Are you using multiple GPS antennas? They can influence each other when in close proximity.


--
Dan, 5J

Thanks Martin,

As I said earlier, the unit did not generate an igc file yesterday which
I assume was due to no GPS lock. Since installing the unit about a
month ago, I've had only one flight near enough to another equipped
glider to produce an alert. I submitted that file to the range analysis
tool and the result was about 6 km around the front and sides with
practically nothing behind. That's reasonable considering my all carbon
fuselage and wings.

Next time I get to the airport, I'll have a look at some of the logs to
see what the GPS lines look like, but I don't thing that's where the
problem lies. The unit never locates any satellites. I'll also try it
with the ADS-B antenna removed from the proximity of the unit.



On 11/24/2016 2:17 PM, Dan Marotta wrote:
I have two GPS antennae, one for the Dynon EFIS and one for the
ClearNav vario. They are on opposite sides of the Stemme's panel,
about 2 feet apart. There is no external antenna for the PF
Portable. It worked just fine on all flights previous to the one
yesterday. I think my ADS-B antenna is closer to the PF Portable unit
now than it was before, maybe 2 inches. Might that be the cause?

On 11/24/2016 11:46 AM, wrote:
Are you using multiple GPS antennas? They can influence each other
when in close proximity.



--
Dan, 5J

Long shot, but when you fabricated the aluminum plate bracket, how did you fix it to the PF unit? Don't know if it came with mounting pts, but maybe steel bolt heads might cause some interference if you went through the case. Power input is OK, right?

A good question. I used very short brass instrument screws to affix the
unit to the aluminum plate. Power is fine unless there's a state other
than on and displaying "0 Satellites" and not on. Maybe the aluminum
plate is the cause (as I've only flown it once while attached to the
plate), but that goes against all I know about ground planes, etc.

I'm going to the airport today and I'll try these things in order after
moving the glider outside:

1. Power the unit up and wait to see if I receive any satellites, if
not then,
2. Move the ADS-B antenna, if not then,
3. Remove all antennae and replace with rubber duckies, if not then,
4. Remove the unit from the glider, use rubber duckies, install
batteries (now the aluminum plate is removed), if not then, WHAT?

I'll look at the .igc files that I've previously downloaded and see what
I can find about the internal GPS (I'm disappointed that it's not an
aviation grade GPS per the FLARM manual). Reload the firmware (which
was updated last month). Report back on my findings.

Sheesh... My MRX PCAS worked perfectly from day one.

Dan

On 11/24/2016 3:36 PM, Duster wrote:
Long shot, but when you fabricated the aluminum plate bracket, how did you fix it to the PF unit? Don't know if it came with mounting pts, but maybe steel bolt heads might cause some interference if you went through the case. Power input is OK, right?

--
Dan, 5J

On Wednesday, November 23, 2016 at 8:08:52 PM UTC-5, Dan Marotta wrote:
It worked fine last time I flew but today, it was stuck on the startup
screen with 0 Satellites showing. I cycled the power a couple of times
with no effect. Both my ClearNav vario and my Dell Streak were both
receiving good GPS locks. The Streak reported 8 satellites.

The PF Portable had been stuck on my glare shield using Dual Lok
fasteners but, a few days ago I fabricated an aluminum plate to bolt the
portable to and then screw the plate to the glare shield. That should
make no difference, but I thought I would tell all.

Being new to this, I have no idea where or how to look for faults. The
PF receives switched power from the DC bus. It has 3 antennae hooked to
it, and its serial port is connected to one of the inputs of a
K6BT-Mux. The other input of the Mux is connected to the serial output
of the CN vario. The Bluetooth radio transmits to the Dell Streak
running XCSoar. On the Streak, I can monitor the interface traffic out
of the Mux. I saw sentences from the Flarm and the ClearNav vario. The
data stream from the CNv had good GPS information and the $PF sentences
appeared to have zeros instead of position data. That would agree with
the startup screen.

It's my understanding that, absent a good GPS signal of its own, the PF
portable should use the GPS data from the vario.

Can anyone offer any advice?
--
Dan, 5J

Was there GPS jamming notam'd at the time?