Silver Paint & Radio Waves

Discussion in 'Instruments / Avionics / Electrical System' started by Flyhighdave, Nov 10, 2016.

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  1. Nov 10, 2016 #1

    Flyhighdave

    Flyhighdave

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    I am building a wood airplane with several internal antennas. I have a paint scheme, which I like very much, that has the primary color as silver.
    It has occurred to me that this paint, which I believe contains metal , may interfer with radio waves getting to & from the antennas. Does anyone have any knowledge of this? Thanks! David
     
  2. Nov 10, 2016 #2

    Aerowerx

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    Not a good idea.

    IIRC, the so called "silver" paint contains aluminum. If so, it can certainly affect the radio waves.

    Either use a non-metallic paint or put the antennas outside the fuselage.
     
  3. Nov 10, 2016 #3

    TFF

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    Most people do not have problems. Plenty of rag & tube with internal antennas. Usually ground plane is a worse problem. I know the wrong metallic paint will mess up older radars.
     
  4. Nov 10, 2016 #4

    Toobuilder

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    My Taylorcraft not only has the traditional layer of UV blocking silver, but is painted silver on top of that. It has an internal antenna feeding a simple handheld (low power) radio and works great.
     
  5. Nov 10, 2016 #5

    N8053H

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    I thought all paint was made with metals some more then others. I would ask is this an antenna with no ground plane or one that uses a ground plane?
     
  6. Nov 10, 2016 #6

    Pops

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    I have used internal copper foil antennas since 1980 and have never had a problem in wood and tube and fabric airplanes . Most of the time they out performed the expensive store bought antennas. I have made copper antennas for com, vor, outer marker.
     
  7. Nov 10, 2016 #7

    BBerson

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    Aluminum dust in paint probably is embedded in insulating resin. A layer of conductive carbon fiber would be different.
     
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  8. Nov 10, 2016 #8

    Himat

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    There is difference between ”metallic paints” and ”radio absorbing paints”.

    Aliminium powder is used to get “silver” paint and make paints opaque, that is really stop light from passing through the paint. Now, these aliminium particles are small, and I guess for the most have a thin oxide layer that make the surface non conductive. Those metal particles will then not make a conductive layer. With the metal particles being small, even more so compared to the wavelength of the radio, they will not affect the signal that much.

    “Radio absorbing paints” like on military equipment is a different story, and a different mix.
     
  9. Nov 10, 2016 #9

    bmcj

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    ^^^ What Bberson and Himat said. The granules of aluminum powder tend to be isolated by the clear paint matrix. It does not form a continuous conductive layer to block signals. If you want to test that yourself, stick an ohmmeter on a layer of silver and check for conductivity.
     
  10. Nov 11, 2016 #10

    FritzW

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    Just about anything near the antenna is going to affect your signal. ...the aluminum in your dope, control cables, wing struts, wiring, other antennas, etc.

    IMHO, your best bet is to start with a well built (homemade), well designed antenna, polarized the right way (vertical for COM, horizontal for NAV), with a good counterpoise\ground plane and good quality, low loss, short as possible coax with good quality connectors. Mount it in the best place you can and it'll probably work fine.

    ...or, walk into your local ham club and ask them the best way to put an antenna in your airplane. They're like EAA guys, they'd be happy to help.


    NM5XD
     
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  11. Nov 12, 2016 #11

    Flyhighdave

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    Thanks for all the comments & advise Homebuilders! I'm happy that most of you think that silver paint is not a big issue. I really like the silver based paint scheme I have & most likely will use it. I'm still a ways off from paint. I have followed Jim Weirs instructions on how to do the antennas & am going to hook them up to an SWR meter to see how the antennas, coax & connections test out. Thanks again. David
     

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