Hello,
If you were implanting à FLARM antenna on a Cessna, which is active (emitting and receiving data), would you stay far from other antennas such as GPS, VHF or T(C)AS ? By how much ?
Kind regards
It seems very unlikely that FLARM would disturb other receivers given the low power output.
FLARM has pretty detailed advice on antenna placement.
There is a post by Sebastian which I had not read before.
@Airborne_Again
Can you confirm on your club aircraft, the number, type and placement of FLARM antenna(s) ?
PetitCessnaVoyageur wrote:
Can you confirm on your club aircraft, the number, type and placement of FLARM antenna(s) ?
The aircraft is a PA28-181 Archer II. There are two RAMI AV-75 antennas for FLARM, one on top and one on the bottom of the aircraft. The built-in range test shows that FLARM reception from the front left is marginal. This is likely because the top antenna is offset to the right and slightly behind the highest point of the cabin area. This was to reuse the location of another antenna that had been removed, but it turned out not to be a good move. OTOH there are a lot of antennas on the aircraft and difficult to find good locations.
PetitCessnaVoyageur wrote:
would you stay far from other antennas
It*s always a good idea to stay away from other antennas as n to the Alarm signal, but the antenna itself can create some interference.
With Alarm-antennas, however, the interference is comparatively small.
The question is what one is trying to achieve with FLARM. It seems that nothing beats an external antenna especially for coverage of the rear sector. Lately someone posted those plots on the Germn forum. They show the transmission performance recorded by the OGN ground stations:
Two antennas are a little better than one and all have more or less good 360 coverage.
But installing an external antenna is crazy expensive on a pressurized aircraft so I did try what I can achiveve on a budget. My current solution is a LX Power Mouse with a single glue on antenna on the right front window:
The results obtained are here. Very decent to the front not so great to the rear:
I also installed this amplifier:
https://shop.jetvision.de/FLARM-BOOSTER
(Currently not available as the crypto miners did discover it also works for them)
The amplifier does only help with the reception, so is not reflected in the above plot. But here is a reception plot (with only 2 flights and little FLARM contacts so no final data yet):
So overall cost is around 1000 Euro so far. For a plane travelling over 150kt I think those are good results as the risk of beeing run over from behind by a glider is rather low. The slower the plane the more effort I would spend on the rear sector.
The FLARM signal is wired to the ADL200 box and then broadcast to SkyDemon, ForeFlight and Garmin Pilot from there. Below a few real life impressions:
That’s excellent data you have Sebastian, and the result you got with the internal antenna seems very efficient.
Sebastian_G wrote:
(Currently not available as the crypto miners did discover it also works for them)
What does that mean ?
Sebastian_G wrote:
The FLARM signal is wired to the ADL200 box and then broadcast to SkyDemon, ForeFlight and Garmin Pilot from there.
And soon, one may feed its certified avionics via ADSB thanks too your new box if I understand correctly.
Attached is my rooftop. You can see the double blade TAS antenna. The FLARM antenna could be in the red circle near the temperature probe (there is a factory installed doubler plate there).
Also, I wondered if someone knows those GAV-868 antennas. @Airborne_Again ?
PetitCessnaVoyageur wrote:
Also, I wondered if someone knows those GAV-868 antennas. Airborne_Again ?
Sorry, no.
PetitCessnaVoyageur wrote:
(Currently not available as the crypto miners did discover it also works for them)What does that mean ?
Helium crytop currency works on the same principle as FLARM with 868 Mhz 25mW transmissions etc. So those people lately did discover they can improve their mining performance with the FLARM amplifiers and purchased them all.
