Beacon interference

[G spot]

My beacon bleeds over to my headset and speaker.  All the time, when it is on.  Any ideas for a fix?

[jetdriven]

You can try a 1000uf electrolytic capacitor from the power lead of it to ground, or running the ground wire back to the battery.  But to be honest, they’re often electrically noisy.  Replace it with a whelen led. 

[0TreeLemur]

I never experienced noise due to the belly beacon before we eliminated it and installed Whelen Orion 650's on the wingtips.  It was the stock Whelen strobe that used a ground to the airframe and a shielded power line.   Is your power wire shielded?  That might solve your problem.   I never liked the way the belly beacon flash illuminated the tops of the wings, so we eliminated that issue.   

[G spot]

I will try the ground to battery.  The power wire is shielded.  My "Beacon" is actually a Whelen strobe, older unit.  Sometimes I seem to forget that computer communication requires better specificity than what I produced in my first post.  

Thanks

[0TreeLemur]

Here is a photo of the one we took out of our '67C.   It was grounded to the airframe, with the shielded +14V power line, and never produced noise.  If yours is the same model and similarly configured, then it probably needs servicing or replacing.   Running a ground wire all the way to the battery sounds like a lot of work, particularly if your battery is in front of the firewall like mine.   I suspect that your problem will remain after you do that, based on my experience.   I could be wrong and often am though....  Good luck.  

 

[carusoam]

Improving grounds go a long way to eliminating noise...

The original belly strobe had an electric motor rotating the light bulbs around, beacon style!

You could here the electric motor running through the headsets...

When you could hear your own thoughts... that meant it was time to grease the belly beacon... 

Now, you probably hear the comforting variable whine of the capicitors loading up... and firing off.

Now that you mention it... the existing original wiring probably doesn’t have any shielding...

Check your strobe installation information to see what was recommended, and compare to what is actually in the plane... a good chance the original wiring was left in place... and is still being used...

Putting in a new wire wouldn’t be very challenging...

PP thoughts only, not an instrument/audio/noise guru...

Best regards,

-a-

[cliffy]

Is your power lead tied to and run parallel  with the antenna cable for your radio? 

[Skates97]

When my old coffee grinder died I put in a new strobe that produced a whine just as Anthony described above. I put this in the avionics bay in back and ran the power line going to the strobe through it, got rid of the noise. 

https://www.aircraftspruce.com/catalog/elpages/lsStrobeNoiseEl.php?clickkey=35795

[G spot]

Thanks folks.  I will be checking for the antenna wire being next to the beacon power wire,  Will run a temporary ground wire externally to see what that does.  If those don't work, I will utilize the strobe noise eliminator. 

[G spot]

Ran a battery ground.  Still have the noise.  I cant tell, without major surgery, if the power wire is touching an antenna wire.  Next move is to try the filter.  Should the filter be installed in line with the Intercom or on the power side of the Beacon?

Thanks

[Skates97]

The instructions said that you can install it on any line experiencing interference. The easiest spot for me was in the avionics bay so I cut the power wire that goes to the beacon/strobe and ran it to the filter and then from the filter to the beacon/strobe.

[MikeOH]

Ideally, you want the filter as close to the source of noise as possible/practical.  Much better to kill the noise at its source than filter out its effects at the susceptible components.  Mid-wire may well work, as it did for Richard, but technically the wire from the beacon to the filter is still radiating noise.

[G spot]

Thanks Mike.  I will try the source first.  I appreciate the advice.
 

[G Miller]

I had noise being induced in one of my VHF radios by local high power commercial FM transmitters. I tried all sorts of quick fixes but the fix that worked was replacement of the 50 year old coax cable. It turns out the outer conductor was not well connected electrically to the RF connectors and RF energy was leaking into radio. 

It may be that your shielded power line is not really shielded due to its age. There should be some simple checks that you can make with a good ohmmeter to determine the quality of the shield.