PowerFlarm BRICK range issues - are we alone????

On Thursday, October 4, 2012 12:45:52 PM UTC-4, Evan Ludeman wrote:
On Oct 4, 12:25*pm, Andy wrote:

On Oct 3, 4:55*pm, wrote:



*PF (with a Butterfly rectangular display) did its thing and allowed

me to take evasive action (the other glider never saw me, or at least

never took evasive action).



How do explain that scenario? If you received a flarm warning for the

other glider then he must have been flarm equipped. *Are you

suggesting that his system didn't show you as a threat, or perhaps

that he chose to ignore the threat?



GY



A couple of possibilities suggest themselves: a) conflict pilot had TA

in view, judged no evasive action was necessary, b) conflict pilot

wasn't able to correctly interpret whatever warning was given. There

were a few guys flying with PF for the first time. Flarm display/

audio doesn't work out real well for 65 yo eyes and ears in some

cases. I heard words to the effect of "Are you $%^&ing KIDDING me?" a

number of times. Being of the bifocal generation now myself, I have

to agree: the power flarm displays aren't what they need to be. Some

of the less important characters on that screen I cannot read without

a magnifier while on the *ground* and my vision is corrected to 20/20

near and far.



T8
Even on the ground, true. While sitting in my cockpit, I can almost make out the little PCAS above/below numbers . . but I absolutely CANNOT tell if that dot before it is a + or a -. That is the first thing they need to make bigger for us 60+ year-olds.

-Jim

On Saturday, October 6, 2012 1:09:26 PM UTC-4, Paul Remde wrote:
Hi John,



The audio function is provided by the display device - either a remote FLARM

or Butterfly or LXNAV display or a PDA. The PowerFLARM Brick unit is

usually mounted in a "buried" location - inside the instrument panel. That

is why it made sense to put the speaker in the display. Rather than adding

an additional external speaker, I think the best approach is to improve the

loudness of the Butterfly Rectangular Display.



Best Regards,



Paul Remde

Cumulus Soaring, Inc.



"John Cochrane" wrote in message

...



On Oct 5, 12:02 pm, "Paul Remde" wrote:

Hi Mike,



OK. I may concede that the Butterfly rectangular remote display has a

speaker that is not as loud as we would hope. Fortunately, there are

alternatives. The Butterfly 57 mm round display is quite loud. So is the

new LXNAV FlarmView. I have one on my desk and it is very loud. I have

them in stock for $255 and will add them to my web site very soon. Until

then you can see details atwww.lxnav.com.



Paul Remde

Cumulus Soaring, Inc.

_______________________________________



Is there no provision for an external speaker? If not, Paul, I hope

you'll lobby flarm to provide it. There are enough wires dangling out

of this thing to assign two of them to audio out. Many people will use

PNAs, PDAs or clearnav for display. Do we have then no audio at all?

John Cochrane

Paul-

I have the Butterfly rectangle display and if it is designed incapable of providing a louder PCAS beep (due to power constraints) then I would be thrilled if FLARM provided a connection for even an external speaker!

-Jim

On Oct 6, 9:41*am, wrote:

A continuous stream of airliners passes over my house. *What I normally see is that PF PCAS function does not detect them until the range is about 2 statute miles. *However, after they have first been detected, they remain displayed until the range reaches 6 statute miles or more.

Gerhard,

Thank you for your interest in this.

To answer you questions:

Is that with the device indoors?

Yes the antenna is indoors, but it is hanging close to a window where
it has a clear view of the airliner's approach path.

ADS-B targets (trianges) or Mode C/S (circles)?

My comments related to the C/S circles. It appears that the range for
first detection is much lower than the range for display after first
detection. However, I see initial detection of ADS-B targets at much
greater range (5 to 6 statute miles).

FYI, Mode S XPDRs also reply to Mode C interrogations.

Since you indicated that there were different threshold settings for
Mode C and Mode S, I wanted to make it clear that the targets were
airliners (with mandatory TCAS) and must have been mode S equipped.

PCAS is limited to 5 NM (the configurator has this wrong unfortunately,
we'll fix that ASAP), trying to set a higher PCASRANGE is ignored.

I didn't use the configurator. Instead I read the data port
specification and the addendum. First I set a high value of PCASRange
but found it was not accepted. I then experimented with different
values to determine the highest value that was accepted and reported
in the dump file. My observations are summarized in my config file
comments -

#
# Sets the PCAS oblique (PCASRANGE) in meters
# Slant (oblique) range is estimated from signal strength
# and is approximate
# Max value appears to be 9250 not 65535 as specified in dataport
addendum
# Values of 9300 and greater will give Amber LED after loading.
#
$PFLAC,S,PCASRANGE,9250
#

The maximum value that I found by experiment is equivalent to 5NM.
Perhaps the dataport addendum has been updated since I downloaded my
copy.

I recommend to leave it above 250 (both Mode S and C). Please let me know how it goes.

I'll do that, but don't know when. The test requires that the traffic
is landing to the East and that I am at home. I also want to set up
the equipment outside so there is no possible antenna issue.

Andy Durbin

Perhaps the dataport addendum has been updated since I downloaded my

copy.

Hi Andy,

thanks for pointing that out. Correct information is now online at

http://www.flarm.com/support/manual/...0_addendum.txt

Best
--Gerhard

On Monday, October 8, 2012 4:44:05 AM UTC-7, wrote:
Hi Andy, thanks for pointing that out. Correct information is now online at http://www.flarm.com/support/manual/..._addendum..txt Best --Gerhard

Gerhard,

Thanks for making the update.

I was able to run some PCAS range tests. I used an outdoor test setup with a clear view of the sky. The only exception to the clear view is that line of sight from the antenna to the airliner arrival route is obstructed by the upper branches of a orange tree until the airliners have approached to within about 2-3 miles. I doubt the signal attenuation is significant.

I tested with baseline settings on Sunday morning and with MTLAC and MTLS set to 300 on Monday morning. It became obvious that attempting to photograph the display when a target was first detected was unreliable, so I set up continuous video recording.

I have not yet reviewed the video from this mornings testing but it was obvious that PCAS performance was not satisfactory. Three airliners flew within about 1 mile, and at about 5000ft, and were never displayed. However, in a few cases the detection seemed to be earlier than with the default settings.

I did notice that the altitude was incorrectly reported for at least 2 of the passing airliners. That makes me wonder if the problem is not sensitivity but incorrect decode of the altitude squawk. If their altitude is incorrectly decoded, and the altitude exceeds the set maximum altitude, then the traffic would not be displayed.

One airliner was ADS-B Out equipped and was displayed continuously for about 12 miles.

I'd like to share the video with you but have no experience with uploading video files. Perhaps you, or someone else, could suggest how I can share .MOV files that are up to 250MByte.

This evening I'll review the video and record the range and altitudes for first detections.

Please let me know if there is another configuration you would like me to evaluate.

Andy

Andy,

I tested with baseline settings on Sunday morning and with MTLAC and MTLS set to 300 on Monday morning. It became obvious that attempting to photograph the display when a target was first detected was unreliable, so I set up continuous video recording.

The PF did accept the settings? You must not restart the PF after a $adsb,configure,... command because these settings are not saved in nonvolatile
memory. What were the PCASRANGE and PCASVRANGE settings?

You could try MTLAC down to 200 or even 150 for testing.

I did notice that the altitude was incorrectly reported for at least 2 of the passing airliners. That makes me wonder if the problem is not sensitivity but incorrect decode of the altitude squawk. If their altitude is incorrectly decoded, and the altitude exceeds the set maximum altitude, then the traffic would not be displayed.

This is probably the systematic problem with legacy XPDRs---it's impossible to
distinguish Mode C and Mode A replies, so some squawks can be interpreted
als altitudes.

I'd like to share the video with you but have no experience with uploading video files. Perhaps you, or someone else, could suggest how I can share .MOV files that are up to 250MByte.

Dropbox, or if you use Google, they recently introduced 'Google Drive'.

Please let me know if there is another configuration you would like me to evaluate.

Thanks for doing the tests already. As above, please just make sure that
the range settings are OK and you don't restart the device after $adsb,configure,...!

F/W update is forthcoming!

Best
--Gerhard

On Oct 8, 11:01*pm, wrote:

Gerhard,

Sorry for the delay in replying.

The PF did accept the settings? *You must not restart the PF after a $adsb,configure,... command because these settings are not saved in nonvolatile
memory. *What were the PCASRANGE and PCASVRANGE settings?

I don't know if the threshold values were accepted but the unit was
not powered down after reading the CF drive. The flarmcfg file
included the following:


$PFLAC,S,PCASRANGE,9250
$PFLAC,S,PCASVRANGE,2500

$adsb,configure,mtlac,300
$adsb,configure,mtls,300

I spent a bit more time reviewing the video files and I see no obvious
difference in the detection range with thresholds set to 300.

General observations for both settings are similar:

Earliest detection is typically 3 - 3.5 statute miles but sometime
less
Sometime there is no detection
Sometimes the displayed altitude is unreasonable
Usually the range ring circle is smallest 15-30 seconds (estimated)
after the aircraft has passed the closest point.
After detection with correct altitude targets usually remain displayed
to 4.5 - 5 miles.

I understand that the aircraft being monitored for these tests are not
collision threats and are well outside the maximum altitude that I
would set for use in flight. I hope, however, that I have
established a baseline against which any updates to PCAS performance
can be evaluated.

Please email me if there is another configuration you would like me to
evaluate.

Andy

Finally got around to installing the brick and display, using the antenna configuration that Peter Kelly documented on Valley Soaring Association's site.
http://www.valleysoaring.net/?page_id=1487
And the Butterfly configurator to build a file complete with Mode S code.
http://www.butterfly-avionics.com/in...core-config-en
From inside the carport and on the trailer ramp - lots of metal right in front of the nose - a transponder was displayed 6NM away. I couldn't see the aircraft through the trees.
Waiting until it's had a decent flight test to see how well things work or not.
Jim

On Oct 15, 4:34*pm, JS wrote:
From inside the carport and on the trailer ramp - lots of metal right in front of the nose - a transponder was displayed 6NM away.

Very good since the max possible range is specified as 5NM!


Andy

Hi Andy,

thanks for the update.

In the meantime, we've found an error in our PCAS module supplier's code that
applies a per-module PCAS sensitivity calibration value.
This will be fixed in the imminent beta release of the PowerFLARM
firmware.

Best
--Gerhard