Radio & Flarm Sensitivity

[Chester Fitchett]

Has anyone had problems with the radio receivers on their Arcus?  I don't think I'mgetting any Flarm hits from the antenna built into the rudder.  

There was another Arcus in my area that sent their Flarm back for repair, and the advice was that Electrostatic Discharges through the rudder into the antenna had caused the receiving electronics to degrade and fail...

I'm now getting suspicious of my radio, the squelch is down to zero and I'm missing radio calls, could be the same issue?

Chester

Arcus M s/n 173

[Mark B]

I am very surprised there is a Flarm aerial in the rudder. I have two Flarm aerials, one on top of the rear panel, one on the bottom in front of the main wheel. I think my radio aerial is in the fin - and I get very good radio reception, except for some interference issues when the engine is running. I have both squelch and vox turned up high to reduce those issues.

[Daniel GUEDON]

Flarm receivers dying from ESD happened in the early days of Flarm on standalone Flarm boxes and on the LX7007 receivers.

On more recent products, more or less the ones produced after 2010, all Flarm receivers are protected internaly against ESD, so no damages from ESD should happen.

As for VHF radios, I believe all of them are protected against ESD since the 60's.

Now this is protection from usual ESD found on gliders fuselage, if you happened to be close of thunder lightnings, this protection might not be good enough and any avionic equipment can suffer from that, receivers being usually first

Both VHF and Flarm antenna are located in the leading edge of the rudder. 

What happens from time to time on glider, is that humidity and/or insects gets there and degrades seriously the antenna, but it takes many years to happen, less time for gliders being much exposed to humidity. Testing with swr meter (or better a VNA) is the way to check the antennas at the plugs side simply by disconnecting them for their receivers. Also a good way to check coax cables integrity (mouses are another enemy of glider electric cables)

So far I have never heard of Arcus being affected by this problem, but it might be worth checking.

Cheers

Daniel

[Andreas]

Mark,
I am in the process of looking for a better spot to locate the Flarm antenna because the current cockpit (back of frontseat headrest) installation is not satisfactory. My second one is in the rudder and ensures satisfactory view but unfortunately more to the back of the glider. I think as well the aerial "in front of the main wheel" is good spot. Where exactly did you put the aerial. Was drilling required, antenna counterbalance installation?
Best regards
Andreas

Mit freundlichen Grüßen
Andreas Balk

[Erik Kurtz]

In our Arcus the there is a FLARM antenna in the rudder, as well as the radio antenna. The (ling) pin on the top of the rear panel is the ELT-Antenna.

Many happy landings, Erik

[Chester Fitchett]

Following up on this, finally got into the Arcus last night.

1 - The flarm antenna in the rudder was the primary antenna, and was working fine.  

2 - The secondary antenna was zip tied to a bunch of wiring inside the panel (as it came from the factory).  As soon as I moved the antenna, targets showed up (tested with the primary unplugged)

So the issue on flarm was poor antenna placement.  As a side point, I've always found Flarm to be well designed.

Still not sure about the radio.  The back seat vario repeater makes a ton of RF interference, so I sanded and copper taped it.  Cleaned right up, can no longer hear the processor chugging away on the radio speaker.

[John Galloway]

In the rudder?   The the fin perhaps?