British Forum > Technical Support

Clicking Sound in Headset

(1/3) > >>

Sparky67:
Hi all,

We have a PilotAware Classic fitted in the aircraft which, except for the odd USB plug losing its connection, has been working fine for a few years. Recently a very intermittent clicking has started in the headsets which, by process of elimination and substitution, appears to be generated by the PAW box.

Once the clicks start, which can be 2 minutes into a flight, an hour into a flight, or not at all, they are only stopped by rebooting the PAW box. The clicks are very brief, sometimes regularly spaced every four or five seconds, or can be more or less frequent.

We have an audio amp fitted between PAW and the Trig radio and can switch the power to that off, so PAW audio can be muted if required without turning the whole box off. Switching that off seems to make no difference.

Has anyone experienced similar headset clicks and can offer us advice on fixing this please?

Thanks,

Martin

PaulSS:
Clicking can also very often be caused by the transponder breaking through or strobes (if they are the older style with a big box to produce the burst of wigglies for the flash). Aberrant noises in the past have been solved simply with a ground loop isolator e.g   https://www.amazon.co.uk/Ground-Isolator-Neoteck-Filter-Eliminator-Black/dp/B076J3GD74/ref=sr_1_1_sspa?adgrpid=58890497451&dchild=1&gclid=CjwKCAjw9uKIBhA8EiwAYPUS3LBktn-ejz4EBQfvassy4Ksd9P0sByx3XPZ8Px5ZmnL5GYO6aOaXihoCZnYQAvD_BwE&hvadid=259008422064&hvdev=c&hvlocphy=9045787&hvnetw=g&hvqmt=e&hvrand=264176390774469784&hvtargid=kwd-294747876947&hydadcr=5082_1827834&keywords=ground+loop+isolator&qid=1629063428&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzSjhDTVpET0Y0WjIwJmVuY3J5cHRlZElkPUEwOTIxNzc4SDkzMjM4U1JGWFJLJmVuY3J5cHRlZEFkSWQ9QTA4ODIyMzEzVjU3SFIyQTlGSExUJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==

Sparky67:
Thanks. The click is still present with the transponder switched off, so it's not RF breakthrough from that. I have a small audio transformer so that can be fitted between the PAW output and the amplifier / Trig radio input. There is also some very low level data noise audible from the Pi which the transformer might help with as well? It’s going to be a few weeks until I can get to the aircraft to work on it again but I will try to remember to report back…!

Martin

steveu:
Which engine does the aircraft have, and is there an effing big capacitor across the rectifier/regulator output?

To alleviate the symptoms, have you tried a ferrite bead on the power input to the PAW and the Trig?

Appreciate all suggestions are not the answer, just symptoms alleviation.

exfirepro:
Hi Martin,

I have heard of a few previous reports of low-level interference from the PAW processor, which is usually induced by proximity between the PAW and aircraft audio wiring, though this is very rare and doesn’t usually present as ‘clicks’. PAW P3i transmissions are very short duration and occur approximately once every 2 seconds - so if they were causing the ‘clicks’ they would be regular, not intermittent.  It is of course possible that something in the PAW is starting to break down and generate unexpected interference - early Classic unit’s are starting to get a bit long in the tooth now, so this could be the case. It would be worth carefully opening the box (after removing the microSD card to avoid breaking it) and making sure everything is correctly located - i.e. the ‘Bridge’ board is fully home on its pins on the motherboard and all other connectors are tight - you mention ‘loose USB connections’ in your OP, but also need to check the antenna, power socket and audio plugs.

Further areas you need to investigate should include proximity of wiring (especially any recent changes) to the PAW unit or its P3i antenna. As already advised, improvements can be achieved by adding ferrite chokes to power and/or audio cables or by installing a ground loop isolator between the PAW audio out and your intercom, or simply by re-routing your wiring. Unfortunately there is no ‘quick-fix’ recipe - it’s just a case of trying all the options.

Please keep us posted on developments.

Best Regards
Peter

Navigation

[0] Message Index

[#] Next page