Degaussing

4763E

4763E

Pre-takeoff checklist
Joined
Oct 1, 2007
Messages
371
Location
Westwood KS
Display Name
Display name:
4763E
Anybody know how? Anybody know anyone who knows how?
 
Do you have a magnetized piece of electronics causing compass error?

If so, another option is to wrap the offending electronics in mu-metal.

The remote annunicator for the GPS was screwing with the compass in my 182. I wrapped it in mu-metal and the problem was eliminated.

Mu-metal ain't cheap but it's cheaper than degaussing and far simpler...if it fixes the problem.
 
Last edited:
timwinters said:
Do you have a magnetized piece of electronics causing compass error?

If so, another option is to wrap the offending electronics in mu-metal.

The remote annunicator for the GPS was screwing with the compass in my 182. I wrapped it in mu-metal and the problem was eliminated.

Mu-metal ain't cheap but it's cheaper than degaussing and far simpler...if it fixes the problem.
Click to expand...

What did you wrap??
 
timwinters said:
Do you have a magnetized piece of electronics causing compass error?

If so, another option is to wrap the offending electronics in mu-metal.

The remote annunicator for the GPS was screwing with the compass in my 182. I wrapped it in mu-metal and the problem was eliminated.

Mu-metal ain't cheap but it's cheaper than degaussing and far simpler...if it fixes the problem.
Click to expand...

And how would you know which electronic was the culprit? And where do you get mu-metal??
 
4763e said:
What did you wrap??
Click to expand...

We wrapped the GPS remote annunciator.

4763e said:
And how would you know which electronic was the culprit? And where do you get mu-metal??
Click to expand...

In our case, the annunciator was immediately below the compass. We dropped it out of the panel and as the AP was lowering it out I watched the compass swing about 20*...mystery solved.

I don't remember where I found the mu-metal but if you google it you'll get a bunch of hits. One is mumetal.com. You can buy it in very thin sheets that are quite pliable.
 
Last edited:
timwinters said:
We wrapped the GPS remote annunciator.



In our case, the annunciator was immediately below the compass. We dropped it out of the panel and as the AP was lowering it out I watched the compass swing about 20*...mystery solved.

I don't remember where I found the mu-metal but if you google it you'll get a bunch of hits. One is mumetal.com. You can buy it in very thin sheets that are quite pliable.
Click to expand...

Thanks, Tim. I appreciate your help!
 
In the early days of color tv the technicians used to degausse the picture tube with a large coil of wire. Someone may just have one lying around. If your are talking airframe it would not work, but something small it would.
 
Pegasus said:
In the early days of color tv the technicians used to degausse the picture tube with a large coil of wire. Someone may just have one lying around. If your are talking airframe it would not work, but something small it would.
Click to expand...

Degaussing consists of exposing the magnetized part to a strong magnetic field (usually caused by an alternating electric current flowing through a wire or coil as mentioned above) and then slowly reducing the magnetic field. Although the current in the degaussing coil goes to zero, the degaussed part is left with a small residual magnetism.

More modern cathode ray tubes contained internal degaussing coils that did their thing every time the crt was switched on. If you have a crt monitor on your computer, you probably have a menu selection to manually start the degauss coils. The picture will rock and shimmy for a few seconds, and then you are degaussed.

-Skip
 
Anthony said:
Be careful, you may make your plane disspear and be transported to another location like this one in the Philly Naval Yard.

http://www.history.navy.mil/faqs/faq21-1.htm
Click to expand...


...Or travel back in time. About the same time our ship was being degaussed at Point Loma, off the tip of Sandy Eggo, a paperback novel found its way aboard about a ship that was sent back to the Greek era because of it being degaussed. It was really, incredibly, superlatively mediocre reading. But it did while away the time.

BTW, a proper degaussing involves high current flowing that-a-way, then a bit less current flowing this-a-way, then a bit less flowing back that-a-way, then a bit less this-a-way, &c, until no current is flowing. True of the old degaussing coil my dad used in the '60s. Remember, it was plugged into the wall, which was AC. The effect was the same, depending on how quickly Dad was run away from the TV we had just sold or repaired.
 
jshawley said:
...About the same time our ship was being degaussed at Point Loma, off the tip of Sandy Eggo,
Click to expand...

Been there! My destroyer DDG31, USS Decatur (Don't bother Googling it, pre-internet.)was degaussed a couple of times there. That was a boring evolution. :sleep:
 
In the early days of color tv the technicians used to degausse the picture tube with a large coil of wire. Someone may just have one lying around. If your are talking airframe it would not work, but something small it would.[/quote]


If a small degaussing ring will help you out try a Best buy store if one is near you. I was at the service desk about a year ago and saw someone have a TV degaussed.
 
If the problem is coming from current flow to an instrument, degaussing won't help. You have to shield it or move the instrument. Degaussing removes/reduces residual magnetism in magnetic material. The problem could also be wiring carrying significant current, like your alternator/generator output wire, being to close to the compass. In my Cherokee (Flite Liner) the compass was mounted at the left end of the panel near where the alternator output came through the firewall. Shutting off the alternator would affect the compass by about 30 degrees. Moved the compass to the top of the glare shield in the center and no more problem.
 
You must log in or register to reply here.
Back
Top