beacon lamp causing interference

bavreze

bavreze

Pre-Flight
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Jun 3, 2015
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Los Angeles
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bavareze
Hi!

every time I turn on the beacon I can hear in the intercom a "wuuu... wuuuu... wuuuu" noise that has same frequency as the beacon lamp. this is annoying. i'm guessing a capacitor between the two beacon terminal would take care of this.

what do you thin? and how many uF shall I put?

Thanks!
 
A bad ground at the beacon power supply will often do that. The current will find other paths such as through cable shielding, causing stray currents that can find their way into the radios or intercom. Sometimes using insulators to isolate the headset jacks from the airframe, and installing separate ground wires back to the intercom, will help to avoid that. Best to check the power supply grounding first.


Or Is the intercom a portable unit? If it has a metal box, see that the box isn't touching the airframe.
 
Both my top beacon and my belly strobe would whine over the headsets unless I used the audio panel's pilot isolate button. It was especially bad when I tried to patch cord in music that was being powered by the cigarette lighter until I put a filter on the audio cord. When I went to an LED top beacon, it solved it for that one. I just put in all LED lights and took out the belly strobe. Quiet.
 
Dan Thomas said:
A bad ground at the beacon power supply will often do that. The current will find other paths such as through cable shielding, causing stray currents that can find their way into the radios or intercom. Sometimes using insulators to isolate the headset jacks from the airframe, and installing separate ground wires back to the intercom, will help to avoid that. Best to check the power supply grounding first.


Or Is the intercom a portable unit? If it has a metal box, see that the box isn't touching the airframe.
Click to expand...

panel monuted garmin 340. i'll check on the beacon ground connection first!
 
It was always an indicator that I needed to clean the ground terminal on the battery. You are hearing the oscillator in the strobe power supply.
 
Very little information.

I have a strobe not a flasher, when the airplane is inside the hanger com antennas pick up the trash that flash tube blasts out. If the airplane is outside there is no noise.

I don't think a flasher would behave like a strobe. You said its in the intercom which would seem like the mic or phone jacks aren't isolated from ground correctly if you are hearing it only through the intercom itself and not being picked up by another radio when receiving a signal.
 
Graueradler said:
It was always an indicator that I needed to clean the ground terminal on the battery. You are hearing the oscillator in the strobe power supply.
Click to expand...


maybe not, the battery is just replaced, the terminal was cleaned at that time too!

bnt83 said:
Very little information.

I have a strobe not a flasher, when the airplane is inside the hanger com antennas pick up the trash that flash tube blasts out. If the airplane is outside there is no noise.

I don't think a flasher would behave like a strobe. You said its in the intercom which would seem like the mic or phone jacks aren't isolated from ground correctly if you are hearing it only through the intercom itself and not being picked up by another radio when receiving a signal.
Click to expand...

I hear it in the headset without radios on.
 
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