FL*RM Integration - Beta Testers

[flyingalan]

16.30 26/10/16
Well, first the good news, Redbox Flarm does O/P $pflaa string when it sees a target.
The problem (which I guess we already knew) is that flarm is very low powered at UHF frequencies and the aircraft flarm antenna polar diagrams (both vertical and horizontal) are horrible on most installations.
Today I borrowed a LX mobile flarm box and took it home. Immediately my redbox started to give $pflaa strings. I then walked a line of sight approx 200 meters to verify it still gave the string with some separation. So far all ok but still no sign of real aircraft.
I then moved my dipole flarm antenna outside the double glazed window and waited. To my delight I finally saw A/C in the circuit at Halton (4Kms). The contacts were very dependent on the source A/C orientation, with A/C facing the contact would be poor unless close, or tail on virtually nothing and contact would disappear. Side on was by far the best. Bearing in mind A/C were typically 1000 ft above me, when facing me the A/C flarm antenna was probably trying to look down through the engine.
To sumarise; it works, best range I saw was 5Kms but indication is very dependent on relative positions vert. and horiz., and orientations. It is likely that the flarm contact in practise will be pretty close before you see him although of course the flarm LED display will still give warning of imminent collision but it will be close !
It will be interesting to compare PAW results which should give better range contact indications because of the higher power. As always antenna positioning is everything for best results.
regards
Alan

[Admin]

Hi Alan,
Great progress.
The release you have, will have the 2 issues Peter described earlier in the thread
1. The Altitude is show incorrectly
2. The Audio constantly repeats for FLARM traffic

I believe both of these are fixed internally

Cant help on the Flarm Range issue I'm afraid - unless you ask the gliders to install a PAW 

Thx
Lee

[Richard]

Alan,
   That's Really Good news... Thanks for taking the time in your tests. Ones I set everything in the aircraft I will also publish my findings too.

[gvpsj]

Re the constant repeating for Flarm traffic. In my lash up of PAW and a PowerFlarm Core I get constant traffic audio for any traffic detected when tried at Enstone this afternoon. No Flarm traffic about at all that I know off. All traffic in range were from Oxford with the 'school' callsign.

[exfirepro]

Hi Guys,

Alan - Glad to hear you are getting positive results with your flarm red box. I agree totally about the poor polar pattern from the standard flarmMouse setup. Due to the very short antenna and very low transmission power, the transmission pattern is very easily blocked unless the whole unit can be mounted up high in the clear away from any obstructions. After analysing performance on my initial tests (using the flarm range analyser at  http://www.kisstech.ch/flarm-liverange/ ), I changed my flarmMouse antenna for a PilotAware P3i end-fed dipole (the same as the one supplied with PAW Classic). While still not perfect due to adjacent metalwork, this produced a significant improvement on the polar diagram during subsequent flights. Other alternatives such as a PilotAware P3i centre fed dipole and a P3i 1/4 wave on a ground plane beneath my pod will be tested when I get the time.

gvpsj - John, as reported above, we know about the constantly repeating audio messages from flarm targets. Lee and I have been working on a solution to this and also previous reports of excessive audio alerts from bearingless targets. I now have an engineering update from Lee, designed to sort this and the incorrect relative altitude display, ready to test but unfortunately weather was against me today. Bear with me, I will get the tests done as soon as practicable.

Please keep feeding back updates. They are all very helpful.

Regards

Peter

[gvpsj]

Thanks, I will keep fiddling about with things ;-))

[exfirepro]

Hi All,

Just to keep you updated, Alan G and I finally managed to get airborne this afternoon (both in the same plane as his is still being fixed) to test Lee's latest PAW/FLARM Integration 'Engineering Build' software. This proved useful as I could monitor the Traffic Screen while Alan watched his Nav System Chart (in his case easyVFR) from the back seat - and we had 2 sets of eyes to keep watch outside as well !!!

We initially headed over towards Loch Leven (nominally routing to Balado) hoping to pass close to gliders taking part in a competition from Portmoak, having seen several active in the area on OGN earlier in the day. Initially, we saw nothing on screen except airliners going in to Edinburgh - nice to see them as proper 'Jet' symbols on both SkyDemon and EasyVFR though! (as well as the Engineering version of PAW, I am also running the latest iOS beta test version of SD). Aircraft 'type specific' symbols will appear with the next release of PilotAware.

As we got closer to Loch Leven, I finally picked up a couple of flarm contacts on my traffic screen as we passed to the north of the Lomond Hills at about 3,000 ft. Alan immediately reported them visible on his Nav Screen well out over Loch Leven, then suddenly lots more appeared from behind the lee of the slope, where - being unable to achieve significant lift to clear the hill, they had been hidden from our approach by the terrain. Even this late in the day we counted at least 15 active gliders on screen at the same time with loads more on the ground at Portmoak. Once out in the clear, they were easily visible as moving 'Glider' symbols at up to 7Km and I was able to grab some screenshots (see below).

As anticipated, relative altitude reporting on the 'Nav' screen is now OK, however we still have a problem with constantly repeating audio alerts. I had a brief chat with Lee on the phone about this on my way home and have provided him with our track log and screenshots to aid investigation.

Regards

Peter & Alan G

[Ian Melville]

That's good news on the range Pete, though obviously the alerts still need sorting.

I notice that There are two with mode S and FLARM in the fur-ball. Lee would it be possible to incorporate the OGN database into PAW, updated with any other updates? That way the FLARM traffic will be decoded.

[gvpsj]

Ian, my PAW - PowerFlarm set up in hardware is all together and portable (on the back of the Europa cockpit 'D' panel') - just needs 12VDC, an audio 'thing' and Flarm V3 display plugging in. You can 'borrow' it for testing if you want whilst my aeroplane and me are repaired.

[exfirepro]

Morning Guys,

Apologies for the 'fur ball' Ian. I could have zoomed in to a better scale to show clear separation I suppose, but didn't think of it 'til later on. With so many aircraft active I was keen to keep my eyes outside the cockpit for potential 'non-transmitting' traffic, and was also busy speaking to a gyro (who didn't appear on screen) who reported inbound to Portmoak from the west to land and came on asking for traffic info but was either not heard by portmoak or more likely they were too busy launching to answer him. I chipped in with info from my nav screen and after obtaining visual confirmation of the level of traffic he thought better of it and reported that he would try again another day. Still no idea where he went !!

PAW also proved its worth on our trip back over the Forth at 5 - 6,000 ft, just outside the eastern boundary of the Edinburgh CTA. Listening on their frequency with listening squawk in operation, they called to advise us of an inbound CAT from the East which would pass overhead East Fortune at around our altitude. I was able to advise them we were just about to commence descent and traffic system equipped. Shortly after this, the jet appeared on screen and we watched it (visually) pass safely above us.

Here are another couple of glider screenshots to whet your appetite.

Regards

Peter

[exfirepro]

Hi again all,

Forgot to mention. As stated a few posts higher up, I swapped my standard flarmMouse antenna for a standard PilotAware P3i end-fed dipole, which significantly improved the radiation (and presumably reception) pattern as per first attachment below. I was still concerned with the gaps to the right and rear, however, so tried simply reversing the flarmMouse on my pod coaming to move the antenna further away from the front strut and nearby wiring (thanks Alan G). The second attachment is the result. Speaks for itself really. I will test other alternatives in due course, but definitely worth a bit of thought about antenna type and placement when working at such low power levels. 

Regards

Peter

p.s. Dave - hope you have plenty in stock for when the 'flarm' guys read this. 

[Admin]

Quick update to all.
Identified the audio issue on flarm contacts, should now be fixed
Await further testing ....

[Admin]

I notice that There are two with mode S and FLARM in the fur-ball. Lee would it be possible to incorporate the OGN database into PAW, updated with any other updates? That way the FLARM traffic will be decoded.

Ian, do you know how to obtain that database ?

Thx
Lee

[Ian Melville]

Massive change to my post. The database that I downloaded was FLARMs which we cannot use. I think you will need to contact OGN to see if the database is available.

Sorry raised hopes there

[exfirepro]

Quick update to all.
Identified the audio issue on flarm contacts, should now be fixed
Await further testing ....

Audio fix update downloaded - weather looking good, so hopefully will get it tested tomorrow and will report outcome.

Regards

Peter