Hiding Colors for Roof Array?

Discussion in 'Satellite and Space Communications' started by AD7N, Jan 14, 2010.

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  1. AD7N

    AD7N Ham Member QRZ Page

    I am planning for a large 2 x 2 EME 2m array to be roof mounted. It's going to look very similar to this one:

    [​IMG]
    (k7xq EME array)


    I would like to paint it something (shiny aluminum is pretty in my eyes, but neighbors think its hideous!) Until they come out with transparent aluminum I think I'm stuck with paint.

    Forest green? Dark gray? navy blue? What about a two-tone blend of gray and blue?

    Anyone have a good idea on color type? Thanks!
     
    Last edited: Jan 14, 2010
  2. KD5RKO

    KD5RKO Ham Member QRZ Page

    I would try light gray. I even found some city proposals that called for it. Look at number 5 in this link ...

    or here , which suggests a "non-reflective matte finish color to blend with the sky, which is the predominant backdrop"

    Just a quick google search that turned these up... I am sure the military has spent a bit on researching this as well
     
  3. VK2TIL

    VK2TIL Ham Member QRZ Page

    Camouflage techniques have been used. There are some utterly bizarre techniques used in the military & commercial worlds but a very simple scheme will make a lot of difference to your proposal.

    Alternate bands of different colours and of different widths are a well-known technique.

    In this case (against the sky), light matte blues & greys would be best.

    The bands can be quite wide, perhaps 2 -5 feet, so it's not a difficult paint job; random widths & joins help anyway.

    Get a couple of spray-cans and have at it!
     
  4. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Any "flat" color that's not reflective will work fine.
     
  5. KC8VWM

    KC8VWM Ham Member QRZ Page

    The reason why I use non reflective "Grey" on my own VHF array is the same reason why the satellite TV industry uses a non reflective Grey on the satellite TV dishes you see on millions of homes across the country.

    You see, the satellite TV dish industry have actually already conducted a lot of research into this.

    To achieve this result, and to ensure the coating I am using will have little effect on the RF currents involving the antenna design, I have decided to used Grey "Rustolium" automotive primer on my VHF array.

    Keep in mind that "paint" doesn't stick to aluminum very well. An automotive primer on the hand does the job very well.

    This is what the final result looks like when primer is used over aluminum applied to my antenna system as seen below:

    [​IMG]




    OO, RR, CU, GL
     
    Last edited: Jan 14, 2010
  6. AD7N

    AD7N Ham Member QRZ Page

    Thanks for all the responses! I will probably try multiple bands of light gray and a dull blue-gray paint. It does make sense too about satellite TV dishes, I'm sure they've invested some heavy research in to figuring out how to make their dishes not "ugly".

    The main question I have is if there is any RF attenuation with the automotive primer? What brand have you used or would recommend?
     
  7. VK2TIL

    VK2TIL Ham Member QRZ Page

    The paint, whether insulating or partly-conductive (some paints have metal particles in them) will not affect performance, at least to any degree that you can measure.

    "Attenuation" is not a problem.

    The paint coating will, at least in theory, affect element length & spacing in a similar way to the effect of insulated wire -v- bare wire in a wire antenna.

    But the effect will be quite minuscule, even at VHF; it will not make any practical difference.
     
    Last edited: Jan 14, 2010
  8. KC8VWM

    KC8VWM Ham Member QRZ Page

    Sorry, I thought I answered that question, the coating is Rustolium brand grey automotive primer.

    This is not a "paint." Primer is a coating material which consists of silane, melamine components, clays and plastics that are radio opaque. Primers are an excellent choice when the intention is to apply a protective coating directly over bare metals including aluminum antenna parts. Primers introduce an increased method of corrosion protection for the metals in which they are applied. Primers are known to exhibit superior durability qualities when compared to paints in terms of harness, flexibility and adhesion properties. Primers typically meet ASTM standards and provide longer lasting durability characteristics when compared with paints. This in part explains why primers are widely used in the automobile and similar industries as a coating protection system. Yes, I was involved in the coatings industry and I have absolutely no idea what I am talking about. :)

    Hope that helps.

    My Best,
     
    Last edited: Jan 14, 2010
  9. AI3V

    AI3V Ham Member QRZ Page

    I must disagree on this point.

    You want to use a paint that is non-conductive, and has no metallic particles in it.

    Obviously gold and silver metal flake, but I understand many black paints are loaded with carbon.

    It was forbidden to paint any antenna or radome on the aircraft carrier.

    As always, you want to test the antenna before and after the paint to insure you don't inadvertently foul things up.

    A useful test would be to paint a few coffee mags, and toss them in the microwave for a minute.

    Rege
     
  10. KC8VWM

    KC8VWM Ham Member QRZ Page

    I must disagree on this point.

    You want to use a paint that is non-conductive, and has no metallic particles in it.

    Radio opaque paint.
    "Aluminum colored" paints often contain small metal flakes to give it a reflective metal appearance. Any paint that attempts to emulate a "metal finish" is a bad choice for that matter.

    Obviously gold and silver metal flake, but I understand many black paints are loaded with carbon.

    "Carbon Black" is a pigment which is added to many black colored paints.

    It was forbidden to paint any antenna or radome on the aircraft carrier.

    This is mainly because many older paints used to contain lead.
    Lead and RF are not a good combination.

    As always, you want to test the antenna before and after the paint to insure you don't inadvertently foul things up.

    You can test a coatings RF attenuation potential by painting something and placing it in the microwave oven. It sparks fly, it's not suitable for RF.

    A useful test would be to paint a few coffee mags, and toss them in the microwave for a minute.

    Yes, I see you already had the same idea. :) My Best.

    Rege
     
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