Painting Receiver/Antenna

[skippydiesel]

• Is it okay to paint a GPS receiver?

 

• If so, are some paints better/less of a problem, than others?

 

I am contemplating purchasing a GPS receiver that only comes in white. I would like to mount it on my glare shield, where everything is mat/flat black.

I imagine the exitance of a white bump  in a "field" of low reflection black, will, at the very least look odd and may even be a visual distraction - hence the above question (also asked of the suppliers).

Edited April 8, 2022 by skippydiesel

[Geoff_H]

The Garmin have don't paint on their body. I think that some paints can attenuate radio frequencies.

[Geoff_H]

Black pigment is often carbon, I expect that would attenuate significantly.  White is titanium dioxide, I think that as it is an insulator and non conductive why every GPS receiver that I have ever seen is white

[spacesailor]

Try ' black plastic sticky ' "  fabulon " .

Then if anything is not as expected ' take it Off ' ( the sticky plastic that is ).

spacesailor

[skippydiesel]

4 hours ago, Geoff_H said:

Black pigment is often carbon, I expect that would attenuate significantly.  White is titanium dioxide, I think that as it is an insulator and non conductive why every GPS receiver that I have ever seen is white

I have two GPS receivers, designed to be placed on the glair shield or similar location, within the aircraft, that are black.

 

I suspect antenna that are designed for exterior mounting are mostly white/cream.

 

Horsham Aviation (Dynon) say okay to paint as long as paint does not contain high metal content (metallic paints). Waiting to hear from Dynon USA.

[Geoff_H]

Carbon black paints are offer used as RF absorbers. Other forms of colouring may have been used on your GPS antennas.

 I would find out what pigments are used in any coloured paint and check the  conductivity of the pigment before applying them else you create a Faraday cage.

 

 

 

[skippydiesel]

1 hour ago, Geoff_H said:

Carbon black paints are offer used as RF absorbers. Other forms of colouring may have been used on your GPS antennas.

 I would find out what pigments are used in any coloured paint and check the  conductivity of the pigment before applying them else you create a Faraday cage.

 

 

 

Thanks Geoff - my other GPS receivers are encased in what I would call black plastic (generic description).

 

I take your point about the carbon/Faraday Cage and will do my best to reduce the likelihood of a paint that inhibits GPS signal.

 

 

 

[skippydiesel]

Do you think that measuring (with a multi meter) the electrical  resistance of the paint would be meaningful?

Edited April 9, 2022 by skippydiesel

[spacesailor]

BUT 

WITH black sticky tape you only  need to put it were it,s needed.

Not on the '  sunny side ' of the antenna.

spacesailor

[Geoff_H]

2 hours ago, skippydiesel said:

Do you think that measuring (with a multi meter) the electrical  resistance of the paint would be meaningful?

Yes a good quality Meyer with a very high input resistance would probably indicate a conductive paint.  A Fluke or equivalent meter, not a cheap Chinese one.

First measure the substrate, without any paint, push the probes as hard as possible into substrate.  The resistance should be infinite.  Then paint the surface, at dry remeasure in the same spot, if the resistance is less than infinite do not use that paint.

I have made a resistor by mixing black carbon ochre with epoxy.  When set I could measure resistance across the part.

Another was is to download an RF Meter on Apple/android and see the effect of putting the phone in a painted box.

Geoff

[skippydiesel]

4 hours ago, Geoff_H said:

Yes a good quality Meyer with a very high input resistance would probably indicate a conductive paint.  A Fluke or equivalent meter, not a cheap Chinese one.

First measure the substrate, without any paint, push the probes as hard as possible into substrate.  The resistance should be infinite.  Then paint the surface, at dry remeasure in the same spot, if the resistance is less than infinite do not use that paint.

I have made a resistor by mixing black carbon ochre with epoxy.  When set I could measure resistance across the part.

Another was is to download an RF Meter on Apple/android and see the effect of putting the phone in a painted box.

Geoff

I have quite the collection of matt/flat black paints - was thinking more along the lines of sticking the "probes" into variose pots of paint & seeing if there is a conductivity.

 

• Conduct/ low resistance likely to have high level of carbon/metal content.
• Nil/low conductivity/high resistance minimal/nil carbon/metal content.

 

Does this sound like a valid hypothesis ??

[Geoff_H]

I think that the dipping in the paint is a great idea.  Just be careful that your favourite colour may fail because the paint carrier that disappears on drying is conductive.  I would not expect so but I am not really certain what is in the carrier.

[RFguy]

Put some in a microwave oven, see if it gets hot.

Make sure you put a glass of water in there also as not to damage the microwave oven. (they dont like having no load)

 

[RossK]

The predominant black pigment is actually Black Iron oxide.

Carbon blacks are typically used where you need a deeper black or "jet black"

[skippydiesel]

Fellow Forum members; This be the response from Dynon (USA);

 

"Yes, it is OK to paint the antenna flat black. Any paint that will adhere to plastic will suffice and it will prevent a white "bump" reflected in your windscreen."

 

Despite Dynons's blanket approval for any paint, I will try out your suggestions & see what happens - may be I can select the least conductive matt black paint.