Implausible Time Records

Dan,

Open your file with a text editor and search for "B190338"
This will put you in the right area.
In each record, after the letter B, the next six bytes are the time.

After B190339 the time jumps back to B190337, which is odd, and leads to
there being two records with a time of 190338, and also 190339.

Odd, but I have seen this before. Maybe you can avoid it in future by
setting a longer fix interval, even 2 seconds might help, but no promises.

I am not seeing any GPS outage around that time. This would be shown by the
Letter "A" in the 25th byte changing to a "V".

Although it does not help a lot, the sequence error seems to happen as you
left the ground, so I guess you were not reversing turns?

I'm not saying this is what OLC are complaining about, just that it is odd
and it might be.

Tim.
--

At 17:06 05 May 2019, Dan Marotta wrote:
I don't see what you're seeing.Â* But how could records be out of
sequence?Â* Maybe because my position apparently reversed while
thermalling during a GPS outage and getting one or two hits and then
another drop out, etc.?

On 5/5/2019 10:43 AM, Tim Newport-Peace wrote:
At 16:26 05 May 2019, Dan Marotta wrote:
Yes, it was from the vario which just started acting up.ÂÂ* The
ClearNav
II display's USB stick did not have the flight.ÂÂ* I may have
neglected
to
download that.

Lately I've been getting a boatload of GPS drop outs.ÂÂ* Maybe that's
because I'm close to the source of the interference testing or maybe
it's because I've cut my antennae cables to length in my cockpit.ÂÂ*
I
now
seem to recall reading that one should not shorten the cables. I know
about reflections due to wavelength/transmission line length, but I
was
unaware that that would affect reception.ÂÂ* Do I need to acquire new
antennae?ÂÂ* The antenna that came with my PF portable was 10 meters
long!ÂÂ* Who needs a big bundle of cable under the panel?

On 5/5/2019 9:49 AM, JS wrote:
On Sunday, May 5, 2019 at 8:38:57 AM UTC-7, Dan Marotta wrote:
For my last three flights I've been getting a message from OLC
warning
of implausible time records in the igc file.ÂÂ* Does anyone know
what
this
means and what I might do to correct the problem? I've asked the
question on the ClearNav forum but haven't gotten a reply yet.

Here's a link to the file if that helps:


https://www.dropbox.com/s/erm01jilim...8Q-01.IGC?dl=0
--
Dan, 5J
Noticed it was from the vario. I'll use a vario file today and see...
Jim
--
Dan, 5J

Looking at the file, there is an out-of-sequence issue:

Checking File C:\Users\Public\Documents\GPS\2019-05-04-CNI-V8Q-01.IGC
---------------------------------------------------------------------
Out of Sequence Error -
B1903383458935N10559992WA0184701874001999104104113 000
B1903393458935N10600013WA0184901876001999112112116 000
B1903373458935N10600035WA0185101877001999115115119 000
B1903383458936N10600057WA0185301878001999119119122 000

Could this be the issue?




--
Dan, 5J

Thanks Tim

I'll increase my time interval to 2 seconds and see if that helps.

Strange that the igc file does not show GPS drop outs since my ClearNav
screen went white with the caption (something like) No GPS.Â* Zero
satellites.Â* And the ClearNav vario said, "Warning no GPS".Â* The
PowerFlarm portable screen also went blank with a "Zero satellites" message.

On 5/5/2019 1:05 PM, Tim Newport-Peace wrote:
Dan,

Open your file with a text editor and search for "B190338"
This will put you in the right area.
In each record, after the letter B, the next six bytes are the time.

After B190339 the time jumps back to B190337, which is odd, and leads to
there being two records with a time of 190338, and also 190339.

Odd, but I have seen this before. Maybe you can avoid it in future by
setting a longer fix interval, even 2 seconds might help, but no promises.

I am not seeing any GPS outage around that time. This would be shown by the
Letter "A" in the 25th byte changing to a "V".

Although it does not help a lot, the sequence error seems to happen as you
left the ground, so I guess you were not reversing turns?

I'm not saying this is what OLC are complaining about, just that it is odd
and it might be.

Tim.

--
Dan, 5J

On Sunday, May 5, 2019 at 3:43:24 PM UTC-7, Dan Marotta wrote:
Thanks Tim

I'll increase my time interval to 2 seconds and see if that helps.

Strange that the igc file does not show GPS drop outs since my ClearNav
screen went white with the caption (something like) No GPS.Â* Zero
satellites.Â* And the ClearNav vario said, "Warning no GPS".Â* The
PowerFlarm portable screen also went blank with a "Zero satellites" message.

On 5/5/2019 1:05 PM, Tim Newport-Peace wrote:
Dan,

Open your file with a text editor and search for "B190338"
This will put you in the right area.
In each record, after the letter B, the next six bytes are the time.

After B190339 the time jumps back to B190337, which is odd, and leads to
there being two records with a time of 190338, and also 190339.

Odd, but I have seen this before. Maybe you can avoid it in future by
setting a longer fix interval, even 2 seconds might help, but no promises.

I am not seeing any GPS outage around that time. This would be shown by the
Letter "A" in the 25th byte changing to a "V".

Although it does not help a lot, the sequence error seems to happen as you
left the ground, so I guess you were not reversing turns?

I'm not saying this is what OLC are complaining about, just that it is odd
and it might be.

Tim.

--
Dan, 5J

That smells of GPS jamming.
Check this page.
https://www.navcen.uscg.gov/pdf/gps/...terference.pdf
I did not have a problem with the vario file today. My antenna has a shortened cable to a MECA divider, then a short SMA-SMA link cable.
Jim

Yes, the GPS jamming usually centers around Alamogordo and ranges out to
about 400 nm.Â* Moriarty is well within that area.Â* I've asked other
local pilots and they don't report so many drop outs.

Maybe there are just too many GPS antennae in my ship.Â* I'll take a look
at a divider for everything except the ADS-B WAAS GPS.Â* Its antenna is
mounted aft of the engine in the Stemme.Â* The rest are on or under the
glare shield.

On 5/5/2019 7:42 PM, JS wrote:
On Sunday, May 5, 2019 at 3:43:24 PM UTC-7, Dan Marotta wrote:
Thanks Tim

I'll increase my time interval to 2 seconds and see if that helps.

Strange that the igc file does not show GPS drop outs since my ClearNav
screen went white with the caption (something like) No GPS.Â* Zero
satellites.Â* And the ClearNav vario said, "Warning no GPS".Â* The
PowerFlarm portable screen also went blank with a "Zero satellites" message.

On 5/5/2019 1:05 PM, Tim Newport-Peace wrote:
Dan,

Open your file with a text editor and search for "B190338"
This will put you in the right area.
In each record, after the letter B, the next six bytes are the time.

After B190339 the time jumps back to B190337, which is odd, and leads to
there being two records with a time of 190338, and also 190339.

Odd, but I have seen this before. Maybe you can avoid it in future by
setting a longer fix interval, even 2 seconds might help, but no promises.

I am not seeing any GPS outage around that time. This would be shown by the
Letter "A" in the 25th byte changing to a "V".

Although it does not help a lot, the sequence error seems to happen as you
left the ground, so I guess you were not reversing turns?

I'm not saying this is what OLC are complaining about, just that it is odd
and it might be.

Tim.
--
Dan, 5J
That smells of GPS jamming.
Check this page.
https://www.navcen.uscg.gov/pdf/gps/...terference.pdf
I did not have a problem with the vario file today. My antenna has a shortened cable to a MECA divider, then a short SMA-SMA link cable.
Jim

--
Dan, 5J

Jamming is directed skyward, they're not taking out car gps's in a 400
nm radius. If you're getting bad time stamps just at liftoff, it's not
likely caused by jamming.

I'm suspicious of your cut-down gps cables, those are tiny wires to be
working on.



On 5/6/19 9:08 AM, Dan Marotta wrote:
Yes, the GPS jamming usually centers around Alamogordo and ranges out to
about 400 nm.Â* Moriarty is well within that area.Â* I've asked other
local pilots and they don't report so many drop outs.

Maybe there are just too many GPS antennae in my ship.Â* I'll take a look
at a divider for everything except the ADS-B WAAS GPS.Â* Its antenna is
mounted aft of the engine in the Stemme.Â* The rest are on or under the
glare shield.

On 5/5/2019 7:42 PM, JS wrote:
On Sunday, May 5, 2019 at 3:43:24 PM UTC-7, Dan Marotta wrote:
Thanks Tim

I'll increase my time interval to 2 seconds and see if that helps.

Strange that the igc file does not show GPS drop outs since my ClearNav
screen went white with the caption (something like) No GPS.Â* Zero
satellites.Â* And the ClearNav vario said, "Warning no GPS".Â* The
PowerFlarm portable screen also went blank with a "Zero satellites"
message.

On 5/5/2019 1:05 PM, Tim Newport-Peace wrote:
Dan,

Open your file with a text editor and search for "B190338"
This will put you in the right area.
In each record, after the letter B, the next six bytes are the time.

After B190339 the time jumps back toÂ* B190337, which is odd, and
leads to
there being two records with a time of 190338, and also 190339.

Odd, but I have seen this before. Maybe you can avoid it in future by
setting a longer fix interval, even 2 seconds might help, but no
promises.

I am not seeing any GPS outage around that time. This would be shown
by the
Letter "A" in the 25th byte changing to a "V".

Although it does not help a lot, the sequence error seems to happen
as you
left the ground, so I guess you were not reversing turns?

I'm not saying this is what OLC are complaining about, just that it
is odd
and it might be.

Tim.
--
Dan, 5J
That smells of GPS jamming.
Check this page.
https://www.navcen.uscg.gov/pdf/gps/...terference.pdf
I did not have a problem with the vario file today. My antenna has a
shortened cable to a MECA divider, then a short SMA-SMA link cable.
Jim

GPS signals are line-of-sight only, and as the problem ocurred at take-off,
the source would have to be very close, like visible.

At 15:44 06 May 2019, kinsell wrote:
Jamming is directed skyward, they're not taking out car gps's in a 400
nm radius. If you're getting bad time stamps just at liftoff, it's not
likely caused by jamming.

I'm suspicious of your cut-down gps cables, those are tiny wires to be
working on.



On 5/6/19 9:08 AM, Dan Marotta wrote:
Yes, the GPS jamming usually centers around Alamogordo and ranges out to

about 400 nm.Â* Moriarty is well within that area.Â* I've asked other
local pilots and they don't report so many drop outs.

Maybe there are just too many GPS antennae in my ship.Â* I'll take a
look

at a divider for everything except the ADS-B WAAS GPS.Â* Its antenna is

mounted aft of the engine in the Stemme.Â* The rest are on or under the

glare shield.

On 5/5/2019 7:42 PM, JS wrote:
On Sunday, May 5, 2019 at 3:43:24 PM UTC-7, Dan Marotta wrote:
Thanks Tim

I'll increase my time interval to 2 seconds and see if that helps.

Strange that the igc file does not show GPS drop outs since my
ClearNav
screen went white with the caption (something like) No GPS.Â* Zero
satellites.Â* And the ClearNav vario said, "Warning no GPS".Â* The
PowerFlarm portable screen also went blank with a "Zero satellites"
message.

On 5/5/2019 1:05 PM, Tim Newport-Peace wrote:
Dan,

Open your file with a text editor and search for "B190338"
This will put you in the right area.
In each record, after the letter B, the next six bytes are the time.

After B190339 the time jumps back toÂ* B190337, which is odd, and
leads to
there being two records with a time of 190338, and also 190339.

Odd, but I have seen this before. Maybe you can avoid it in future
by
setting a longer fix interval, even 2 seconds might help, but no
promises.

I am not seeing any GPS outage around that time. This would be shown

by the
Letter "A" in the 25th byte changing to a "V".

Although it does not help a lot, the sequence error seems to happen
as you
left the ground, so I guess you were not reversing turns?

I'm not saying this is what OLC are complaining about, just that it
is odd
and it might be.

Tim.
--
Dan, 5J
That smells of GPS jamming.
Check this page.
https://www.navcen.uscg.gov/pdf/gps/...terference.pdf
I did not have a problem with the vario file today. My antenna has a
shortened cable to a MECA divider, then a short SMA-SMA link cable.
Jim

I've also had drop outs with my Trig TN-70 and its antenna, though not
as often as with my soaring GPSs.

Yes, the wires are tiny, but it was pretty simple to desolder them from
the puck, clip the cable to length, strip, tin, and solder.Â* I did that
for 3 antennae and they generally work fine, but lately have acting up.

I'm looking at THESE
https://www.amazon.com/CIROCOMM-Antenna-Ceramic-25x25x2mm-Geekstory/dp/B078Y2WNY6?ref_=Oct_TopRatedC_3248676011_1&pf_rd_p =57ac2d87-b669-53fa-a2b6-2c15e8d66f28&pf_rd_s=merchandised-search-6&pf_rd_t=101&pf_rd_i=3248676011&pf_rd_m=ATVPDKIKX 0DER&pf_rd_r=GNQVSWJ3FAVNDTDDJJDS&pf_rd_r=GNQVSWJ3 FAVNDTDDJJDS&pf_rd_p=57ac2d87-b669-53fa-a2b6-2c15e8d66f28
as replacements.Â* Any comments?Â* I wonder if that IPEX connector is a
push fit on the built in SMA connectors on the devices.Â* I'm also
considering replacing the modified antennae with factory new units and
using the longer cables to mount them on opposite canopy rails in the
Stemme.Â* Those should be about a meter apart.

On 5/6/2019 9:44 AM, kinsell wrote:
Jamming is directed skyward, they're not taking out car gps's in a 400
nm radius.Â* If you're getting bad time stamps just at liftoff,Â* it's
not likely caused by jamming.

I'm suspicious of your cut-down gps cables, those are tiny wires to be
working on.



On 5/6/19 9:08 AM, Dan Marotta wrote:
Yes, the GPS jamming usually centers around Alamogordo and ranges out
to about 400 nm.Â* Moriarty is well within that area.Â* I've asked
other local pilots and they don't report so many drop outs.

Maybe there are just too many GPS antennae in my ship.Â* I'll take a
look at a divider for everything except the ADS-B WAAS GPS.Â* Its
antenna is mounted aft of the engine in the Stemme. The rest are on
or under the glare shield.

On 5/5/2019 7:42 PM, JS wrote:
On Sunday, May 5, 2019 at 3:43:24 PM UTC-7, Dan Marotta wrote:
Thanks Tim

I'll increase my time interval to 2 seconds and see if that helps.

Strange that the igc file does not show GPS drop outs since my
ClearNav
screen went white with the caption (something like) No GPS. Zero
satellites.Â* And the ClearNav vario said, "Warning no GPS". The
PowerFlarm portable screen also went blank with a "Zero satellites"
message.

On 5/5/2019 1:05 PM, Tim Newport-Peace wrote:
Dan,

Open your file with a text editor and search for "B190338"
This will put you in the right area.
In each record, after the letter B, the next six bytes are the time.

After B190339 the time jumps back toÂ* B190337, which is odd, and
leads to
there being two records with a time of 190338, and also 190339.

Odd, but I have seen this before. Maybe you can avoid it in future by
setting a longer fix interval, even 2 seconds might help, but no
promises.

I am not seeing any GPS outage around that time. This would be
shown by the
Letter "A" in the 25th byte changing to a "V".

Although it does not help a lot, the sequence error seems to
happen as you
left the ground, so I guess you were not reversing turns?

I'm not saying this is what OLC are complaining about, just that
it is odd
and it might be.

Tim.
--
Dan, 5J
That smells of GPS jamming.
Check this page.
https://www.navcen.uscg.gov/pdf/gps/...terference.pdf
I did not have a problem with the vario file today. My antenna has a
shortened cable to a MECA divider, then a short SMA-SMA link cable.
Jim



--
Dan, 5J

On 5/6/19 10:32 AM, Dan Marotta wrote:
I've also had drop outs with my Trig TN-70 and its antenna, though not
as often as with my soaring GPSs.

Do they correlate with the engine running? If so, might be ignition noise.



Yes, the wires are tiny, but it was pretty simple to desolder them from
the puck, clip the cable to length, strip, tin, and solder.Â* I did that
for 3 antennae and they generally work fine, but lately have acting up.

It's easy to overheat the dielectric in the coax, causing loss of signal
strength.



I'm looking at THESE
https://www.amazon.com/CIROCOMM-Antenna-Ceramic-25x25x2mm-Geekstory/dp/B078Y2WNY6?ref_=Oct_TopRatedC_3248676011_1&pf_rd_p =57ac2d87-b669-53fa-a2b6-2c15e8d66f28&pf_rd_s=merchandised-search-6&pf_rd_t=101&pf_rd_i=3248676011&pf_rd_m=ATVPDKIKX 0DER&pf_rd_r=GNQVSWJ3FAVNDTDDJJDS&pf_rd_r=GNQVSWJ3 FAVNDTDDJJDS&pf_rd_p=57ac2d87-b669-53fa-a2b6-2c15e8d66f28
as replacements.Â* Any comments?Â* I wonder if that IPEX connector is a
push fit on the built in SMA connectors on the devices.Â* I'm also
considering replacing the modified antennae with factory new units and
using the longer cables to mount them on opposite canopy rails in the
Stemme.Â* Those should be about a meter apart.

On 5/6/2019 9:44 AM, kinsell wrote:
Jamming is directed skyward, they're not taking out car gps's in a 400
nm radius.Â* If you're getting bad time stamps just at liftoff,Â* it's
not likely caused by jamming.

I'm suspicious of your cut-down gps cables, those are tiny wires to be
working on.



On 5/6/19 9:08 AM, Dan Marotta wrote:
Yes, the GPS jamming usually centers around Alamogordo and ranges out
to about 400 nm.Â* Moriarty is well within that area.Â* I've asked
other local pilots and they don't report so many drop outs.

Maybe there are just too many GPS antennae in my ship.Â* I'll take a
look at a divider for everything except the ADS-B WAAS GPS.Â* Its
antenna is mounted aft of the engine in the Stemme. The rest are on
or under the glare shield.

On 5/5/2019 7:42 PM, JS wrote:
On Sunday, May 5, 2019 at 3:43:24 PM UTC-7, Dan Marotta wrote:
Thanks Tim

I'll increase my time interval to 2 seconds and see if that helps.

Strange that the igc file does not show GPS drop outs since my
ClearNav
screen went white with the caption (something like) No GPS. Zero
satellites.Â* And the ClearNav vario said, "Warning no GPS". The
PowerFlarm portable screen also went blank with a "Zero satellites"
message.

On 5/5/2019 1:05 PM, Tim Newport-Peace wrote:
Dan,

Open your file with a text editor and search for "B190338"
This will put you in the right area.
In each record, after the letter B, the next six bytes are the time.

After B190339 the time jumps back toÂ* B190337, which is odd, and
leads to
there being two records with a time of 190338, and also 190339.

Odd, but I have seen this before. Maybe you can avoid it in future by
setting a longer fix interval, even 2 seconds might help, but no
promises.

I am not seeing any GPS outage around that time. This would be
shown by the
Letter "A" in the 25th byte changing to a "V".

Although it does not help a lot, the sequence error seems to
happen as you
left the ground, so I guess you were not reversing turns?

I'm not saying this is what OLC are complaining about, just that
it is odd
and it might be.

Tim.
--
Dan, 5J
That smells of GPS jamming.
Check this page.
https://www.navcen.uscg.gov/pdf/gps/...terference.pdf
I did not have a problem with the vario file today. My antenna has a
shortened cable to a MECA divider, then a short SMA-SMA link cable.
Jim



--
Dan, 5J

Not necessarily related, but I noticed that your Firmware is dated
10-Feb-2017. I feel sure that there have been updates since then.

At 15:08 06 May 2019, Dan Marotta wrote:
Yes, the GPS jamming usually centers around Alamogordo and ranges out to
about 400 nm.Â* Moriarty is well within that area.Â* I've asked other
local pilots and they don't report so many drop outs.

Maybe there are just too many GPS antennae in my ship.Â* I'll take a look

at a divider for everything except the ADS-B WAAS GPS.Â* Its antenna is
mounted aft of the engine in the Stemme.Â* The rest are on or under the
glare shield.

On 5/5/2019 7:42 PM, JS wrote:
On Sunday, May 5, 2019 at 3:43:24 PM UTC-7, Dan Marotta wrote:
Thanks Tim

I'll increase my time interval to 2 seconds and see if that helps.

Strange that the igc file does not show GPS drop outs since my
ClearNav
screen went white with the caption (something like) No GPS.Â* Zero
satellites.Â* And the ClearNav vario said, "Warning no GPS".Â* The
PowerFlarm portable screen also went blank with a "Zero satellites"
message.

On 5/5/2019 1:05 PM, Tim Newport-Peace wrote:
Dan,

Open your file with a text editor and search for "B190338"
This will put you in the right area.
In each record, after the letter B, the next six bytes are the time.

After B190339 the time jumps back to B190337, which is odd, and
leads
to
there being two records with a time of 190338, and also 190339.

Odd, but I have seen this before. Maybe you can avoid it in future by
setting a longer fix interval, even 2 seconds might help, but no
promises.

I am not seeing any GPS outage around that time. This would be shown
by
the
Letter "A" in the 25th byte changing to a "V".

Although it does not help a lot, the sequence error seems to happen
as
you
left the ground, so I guess you were not reversing turns?

I'm not saying this is what OLC are complaining about, just that it
is
odd
and it might be.

Tim.
--
Dan, 5J
That smells of GPS jamming.
Check this page.
https://www.navcen.uscg.gov/pdf/gps/...terference.pdf
I did not have a problem with the vario file today. My antenna has a
shortened cable to a MECA divider, then a short SMA-SMA link cable.
Jim

--
Dan, 5J

You're correct, Tim.Â* I just checked and the latest firmware for the
vario is dated 5/10/18.Â* I'll download that today.Â* Still, I'm getting
the same error message from OLC for the ClearNav II computer with the
latest firmware installed.

On 5/6/2019 10:04 AM, Tim Newport-Peace wrote:
Not necessarily related, but I noticed that your Firmware is dated
10-Feb-2017. I feel sure that there have been updates since then.

At 15:08 06 May 2019, Dan Marotta wrote:
Yes, the GPS jamming usually centers around Alamogordo and ranges out to
about 400 nm.ÂÂ* Moriarty is well within that area.ÂÂ* I've asked other
local pilots and they don't report so many drop outs.

Maybe there are just too many GPS antennae in my ship.ÂÂ* I'll take a look
at a divider for everything except the ADS-B WAAS GPS.ÂÂ* Its antenna is
mounted aft of the engine in the Stemme.ÂÂ* The rest are on or under the
glare shield.

On 5/5/2019 7:42 PM, JS wrote:
On Sunday, May 5, 2019 at 3:43:24 PM UTC-7, Dan Marotta wrote:
Thanks Tim

I'll increase my time interval to 2 seconds and see if that helps.

Strange that the igc file does not show GPS drop outs since my
ClearNav
screen went white with the caption (something like) No GPS.ÂÂ* Zero
satellites.ÂÂ* And the ClearNav vario said, "Warning no GPS".ÂÂ* The
PowerFlarm portable screen also went blank with a "Zero satellites"
message.
On 5/5/2019 1:05 PM, Tim Newport-Peace wrote:
Dan,

Open your file with a text editor and search for "B190338"
This will put you in the right area.
In each record, after the letter B, the next six bytes are the time.

After B190339 the time jumps back to B190337, which is odd, and
leads
to
there being two records with a time of 190338, and also 190339.

Odd, but I have seen this before. Maybe you can avoid it in future by
setting a longer fix interval, even 2 seconds might help, but no
promises.
I am not seeing any GPS outage around that time. This would be shown
by
the
Letter "A" in the 25th byte changing to a "V".

Although it does not help a lot, the sequence error seems to happen
as
you
left the ground, so I guess you were not reversing turns?

I'm not saying this is what OLC are complaining about, just that it
is
odd
and it might be.

Tim.
--
Dan, 5J
That smells of GPS jamming.
Check this page.
https://www.navcen.uscg.gov/pdf/gps/...terference.pdf
I did not have a problem with the vario file today. My antenna has a
shortened cable to a MECA divider, then a short SMA-SMA link cable.
Jim
--
Dan, 5J


--
Dan, 5J