copper tape on servos?

[dalbert02]

Yesterday I went to a UAV convention and noticed that many companies cover thier servos with copper tape. I was wondering why. Some said to reduce interference with GPS recievers but I thought copper tape would only attenuate low frequency rf noise, the Ghz stuff would still get thru. Any thoughts?

More pics of the show here: http://www.rcgroups.com/forums/showthread.php?t=538447&page=2

-dave

[vintage1]

No. Foil screening works better at short wavelengths..where the magnetic component is very small.

[Bruce Abbott]

It depends on the nature of the 'RF noise', and the extent of the screening. Low frequency electrostatic fields are blocked, but magnetic fields can get through. At high frequencies both magnetic and electric fields are blocked (not that the magnetic component is 'small', it's just that it can't penetrate the foil).

However, a small gap could still be large enough to let very high frequency electromagnetic radiation escape. As an example, your microwave oven door has a screen that blocks microwaves, but allows visible light to pass through.

[MatC]

Could perhaps work along the same lines as covering your receiver in tin foil: blocks interference from microwave frequencies. Or maybe they are trying to look posh/expensive.

[mike50]

Perhaps it is like wearing tin-foil hats --- to prevent aliens from taking over control of the UAV? :)

Mike

[MatC]

PS... might be to help heat dissipation. I've noticed some digital servos have heatsinks coming out of the sides, perhaps the copper plating helps further with that. That pic looks more like shielding though, perhaps it is both?

[billyzelsnack]

Things from the future are shiny. Things from farther in the future are spherical. I for one look forward to shiny spherical servos.

[Cas123]

Maybe they're metal geared servos and they want to attenuate the noise.

I suppose the thing to consider is that being a UAV, the signals from the ground control Transmitter may be rather weaker than what we experience with R/C aircraft because of the distances involved. Therefore onboard generated noise may be more of an issue. Although I don't notice any grounding straps on the metal rudder control linkages.

Ron...

[XJet]

We've *never* had servo noise affect our GPS receivers. Any harmonics from the servo clock/switching or brush arcing are of a very low magnitude at GPS frequencies.

Perhaps it's just so that they can resell good old (cheap) RC model servos as expensive "UAV servos"? (and I'm only speaking with my tongue *slightly* in my cheek here).

[Cas123]

Must admit they look very swish. :cool: At least a $200 touch. :D
Wonder if you can get them in pastel colors, or metalic. :p

Ron...