Constant click noise coming from PA

[g-egbs]

We have connected PA through an amplifier to the intercom, to enable the audio warnings to be heard.
Now we have a constant and regular click sound coming through the headset. Nice to know PA is working but irritating after a while.
I've checked with another PA owner at Shobdon & he confirmed that they also have this sound.
Any suggestions.
David

[JCurtis]

What frequency would you say these are, 1 a second, 5 seconds etc. as that may help pin it down to a specific event going on?

[Paul_Sengupta]

If it's every 1.8 seconds or so, it's probably the PAW transmitter. You'll have to move everything around or shield the audio cables to stop them receiving the RF.

[exfirepro]

David,

We have had reports of interference appearing when PAW audio is connected to aircraft audio systems. These have however been very few and the users have usually managed to cure the problem by fitting a ground loop isolator such as:

https://www.amazon.co.uk/d/Electronics-Photo/Aukey-AUKEY-Ground-Loop-Isolator/B01LYYRT7M/ref=sr_1_1?ie=UTF8&qid=1490394034&sr=8-1&keywords=aukey+ground+loop+isolator

....between the PAW audio out and their system audio input. Definitely worth a try. It's also possible that your amplifier could be making things worse by amplifying any low level interference as well as the signal, especially if the amplifier is high gain.

Regards

Peter

[T67M]

Every couple of seconds is about the flash rate of most aircraft strobes. Are you sure it isn't the amplifier picking up the discharge from these rather than something generated by the PAw?

[g-egbs]

Definitely not the strobe, sound accurs when strobes are off.

[g-egbs]

Fitted the ground loop and problem solved.
Thank you

[exfirepro]

David,

Great news! Glad that worked for you. Thanks for getting back to us to let us know. Hopefully others will see this and spread the word. Happy Flying! 

Regards
 
Peter

[Bill Maxwell]

or is it that you fitted the isolator and that fixed a ground loop problem? 

[crisisguy]

+1 on the ground loop isolator

Had some noise from the strobes and the isolator cured it

[exfirepro]

Thanks for letting us know. I have a colleague at East Fortune who has just changed his PAW to a new aircraft with a transponder and was initially getting audio interference  - also cured by fitting a ground loop isolator between PAW and his intercom. AlanG has also fitted one to clean up his PAW audio. It all adds to the knowledge pool. I now have two ground loop isolators 'on hand' so I can try them as a first fix attempt if anyone else local tells me they are experiencing audio interference.

Regards

Peter

[JCurtis]

The isolators treat the symptom, although the ideal would be to identify and fix the root cause that will still be lurking underneath somewhere.

[exfirepro]

Hi Jeremy,

Very valid point, but the ground loop isolator at least allows us to continue to use the equipment while reading up on ground loops, trying to work out where the interference is coming from in the first place and working out the best way to remove it more effectively. 

Regards

Peter