L-Nav question

[Greg Arnold[_2_]]

Does a newer logger (such as the one in the PowerFlarm) work OK with an
L-Nav, or is there a reason for an L-Nav owner to keep the old model 20
logger?

[Paul Remde]

Hi Greg,

Since you can't enter tasks or select an active waypoint in the PowerFLARM,
it can't send the distance to the active waypoint to the L-NAV. Also, it
sends data at 19200 baud while the L-NAV needs 4800 baud.

The GPS-NAV is really the best thing to connect to an L-NAV. It is the only
device that sends airport elevations to the L-NAV.

Best Regards,

Paul Remde

"Greg Arnold" > wrote in message
...
> Does a newer logger (such as the one in the PowerFlarm) work OK with an
> L-Nav, or is there a reason for an L-Nav owner to keep the old model 20
> logger?

[Darryl Ramm]

On Oct 27, 10:29*am, "Paul Remde" > wrote:
> Hi Greg,
>
> Since you can't enter tasks or select an active waypoint in the PowerFLARM,
> it can't send the distance to the active waypoint to the L-NAV. *Also, it
> sends data at 19200 baud while the L-NAV needs 4800 baud.
>
> The GPS-NAV is really the best thing to connect to an L-NAV. *It is the only
> device that sends airport elevations to the L-NAV.
>
> Best Regards,
>
> Paul Remde
>
> "Greg Arnold" > wrote in message
>
> ...
>
> > Does a newer logger (such as the one in the PowerFlarm) work OK with an
> > L-Nav, or is there a reason for an L-Nav owner to keep the old model 20
> > logger?
>
>

Just one point -- before the 4800 baud comment scares a bunch of
people. Existing Flarm products support 4800 baud NMEA output and I
see no reason that the PowerFLARM would not - it is an obvious need,
its the industry standard/default NMEA baud rate, and would break lots
of things if it didn't. Its easy to configure Flarm Baud rates (e.g
with the Flarm tool). The default rate on Flarm products has been
19200 baud and I assume the PowerFLARM will be the same, if you change
it to 4800 baud the device cannot put the Flarm traffic data into the
NMEA stream (4800 baud is too slow to do this) but then if you have a
device that can only work at 4800 baud it is not going to know what to
do with the Flarm NMEA traffic data anyhow.

I'll confirm this after I steal a PowerFLARM from Urs on Saturday :-)

Darryl

[Dave Nadler]

On Oct 27, 1:45*pm, Darryl Ramm > wrote:
> Just one point -- before the 4800 baud comment scares a bunch of
> people. Existing Flarm products support 4800 baud NMEA output and I
> see no reason that the PowerFLARM would not - it is an obvious need,
> its the industry standard/default NMEA baud rate, and would break lots
> of things if it didn't. Its easy to configure Flarm Baud rates (e.g
> with the Flarm tool). The default rate on Flarm products has been
> 19200 baud and I assume the PowerFLARM will be the same, if you change
> it to 4800 baud the device cannot put the Flarm traffic data into the
> NMEA stream (4800 baud is too slow to do this) but then if you have a
> device that can only work at 4800 baud it is not going to know what to
> do with the Flarm NMEA traffic data anyhow.
>
> I'll confirm this after I steal a PowerFLARM from Urs on Saturday :-)
>
> Darryl

Correct, baud rate(s) are easily configurable...
Best Regards, Dave

[[email protected]]

On Oct 27, 12:01*pm, Greg Arnold > wrote:
> Does a newer logger (such as the one in the PowerFlarm) work OK with an
> L-Nav, or is there a reason for an L-Nav owner to keep the old model 20
> logger?

Flarm logger is independant of other stuff.
If the system you have now uses integrated LNav/Model 20/ PDA or other
display you have a working system.
Delete the Model 20 and you have nothing to accept ASI info from the
LNav and process to get real wind calculation.
Flarm does no navigation, just safety info and logging.
If you have another vario/ glide computer/ display, then this doesn't
matter.
In any case, Model 20 is a good back up.
FWIW-
UH

[Darryl Ramm]

On Oct 27, 5:17*pm, wrote:
> On Oct 27, 12:01*pm, Greg Arnold > wrote:
>
> > Does a newer logger (such as the one in the PowerFlarm) work OK with an
> > L-Nav, or is there a reason for an L-Nav owner to keep the old model 20
> > logger?
>
> Flarm logger is independant of other stuff.
> If the system you have now uses integrated LNav/Model 20/ PDA or other
> display you have a working system.
> Delete the Model 20 and you have nothing to accept ASI info from the
> LNav and process to get real wind calculation.
> Flarm does no navigation, just safety info and logging.
> If you have another vario/ glide computer/ display, then this doesn't
> matter.
> In any case, Model 20 is a good back up.
> FWIW-
> UH

(not relevent to the orignal question but hopefuly interesting to some
folks...)

The PowerFLARM is independent until you want to get its traffic data
out (which most pilots probalby will just use the intental screen).
Then some folks might think they are stuck, but don't fret...

Like other Flarm systems the PowerFLARM output NMEA serial data with
extensions that provide traffic data for external displays like a
ClearNav or PDA/PNA running SeeYou, WinPilot, XCSoar, LK8000, etc.
(They also have a separate data port for the little Butterfly like
displays). Some pilots, especially those with large displays, may want
to see traffic (and warning pop-ups) displayed on those devices, to do
that you need to connect to the GPS in the PowerFLARM. The problem is
if you currently connect to a flight computer like a Cambridge 302 or
similar device to get it's enhanced NMEA data with say TAS (for SeeYou
Mobile, WinPilot etc. to calculate their own wind) or Wind data (for
ClearNav) then you need to combing two GPS sources. And bada bing...
magic boxes exists that let you merge together two NMEA soruces. The
obvious one for us is the K6 NMEA Mux (http://tinyurl.com/2cvfl4g). I
know Cumulus Soaring will be selling those in the USA to support
PowerFLARM adopters who want to do this (most will not).

Personally I'll probalby be using a PowerFLARM brick mounted behind
the panel and the ButterFly display it comes with mounted high on my
glareshield for the warnings etc. but I want to use the traffic data
out of the PowerFLARM to drive a larger SeeYou Mobile display so I'll
likely be buying a K6 Mux to combine that traffic data with my C302
NMEA data-out.

Darryl

[weersch[_2_]]

Hi Greg.
Back to the LNAV.

It all depends on what functionality you want to get out of the LNAV.
1: Vario only
2: Vario + Wind + Final Glide with manual arrival altitude
3: Vario + Wind + Final Glide with automatic arrival altitude

For #1 you only need the LNAV. No GPS needed
For #2 you need the LNAV + a GPS source that provides Location and
Waypoint info (NMEA GPRMC and GPRMB sentences)
For #3 you need the LNAV + a GPS source like above + a source for the
Waypoint Elevation info (proprietary Cambridge PCAIB sentence)

Obviously the complete LNAV system solution (LNAV + GPSNAV20 + 303
display) provides the full #3 functionality.
If you cut out the 303 display, you cannot select a waypoint that the
LNAV needs and you can only achieve option #1
Same if you cut out the GPSNAV. Only option #1 is left.

The previous owner of my ship decided to go with and LNAV only (no
GPSNAV, no 303) + Garmin GPSMAP195 for the moving map display, when he
took delivery of the ship in the late nineties.
The GPSMAP195 is a huge brick and a huge power hog in the cockpit.
So, I removed that immediately and replaced it with a IPAQ310 (which I
am very happy with)
However, this left me without a GPS source for the LNAV.
I decided to hook up a small Garmin Etrex, which has the possibility
to output the required NMEA GPRMC and GPRMB sentences).
The Etrex lets you select waypoints, but it does not provide Waypoint
Elevation (NMEA PCAIB sentence) for the automatic arrival altitude
So that limited me to option #2.
I build a small Microcontroller application that actually adds the
Waypoint Elevation (PCAIB) sentence to the stream.
Now I have the full LNAV functionality with the Garmin Etrex (without
GPSNAV and 303)

If you (or any other LNAV users) want to have more information on
that, you can contact me offline.

I personally have no need to secure logging. My IPAQ310 does all
necessary logging for OLC uploads.
I will be installing a PowerFlarm as soon as it comes out.
My PF will be feeding GPS data to the Trig TT21 (for ADS-B out) and to
the IPAQ310 (because the internal GPS is not great).
But my PF will not be connected to the LNAV.

Conclusion:
- There is no purpose to connect a logger to the LNAV if the logger
does not let you select a waypoint (no GPRMB sentence).
- If the Logger does let you select a waypoint (output GPRMB sentence)
but is not Cambridge, you can achieve only option #2.
- If you want full LNAV fucntionality with a Non-Cambridge GPS (that
lets you select a waypoint), contact me off-line.

Hope that helps.
Hans Van Weersch