INVISIBLE AM/FM antenna on windshield cools cartoo

Unknown

I inquired with a certain gentlemen with a work history in electronic research about the subject information because I don't want the optional roof antenna, nor do I want to have a fender antenna; in fact, my car will have a delete plate over the radio location and also have hidden within the glove box an AM/FM/cassette, remotely controlled, plus a six (6) CD changer probably hidden in the trunk. Here is what he recommended:

Go to an automotive store and purchase a sheet of metallic window tint plastic material. If your automotive store does not have such material, go to your hardware store and find the same type of tinting material as used for building work.

The material comes in sheets that look like sheets of transparent plastic. The sheets are large enough to cover your entire
windshield. You need to purchase a sheet of material that has a very thin sheet of metal imbedded in it. The metal is so thin that it is transparent. This metal film is usually used to stop the infrared radiation from the sun from entering your car. This greatly reduces the heat build-up in your car (you will like that).

Warning; some plastic tinting sheets are just a coloring, and have no metal film; these will not work. I am not sure how to tell the difference except by calling the manufacturer.

WARNING: The legal automotive transparency reduction limit in the USA is something like 94%. Do not make it difficult to see out of the windshield (especially at night). Get a tinting film that does not visibly reduce your visibility.

You then need to attach this metal film to the inside of your windshield. It is very critical that you leave a 1/2 inch gap around the entire circumference of the windshield (to prevent RF shorting to the chassis).

Next you run a coaxial cable from the radio up the post and to the top center of the windshield (under the headliner). At the top center of the windshield, you attach the shield of the coax to the metal of the car, and then the center connector to a copper "patch". The copper patch is a thin flexible patch (size 4 inches long by 1.5 inches wide) that you stick to the plastic film. This provides a capacitive connection to the imbedded metal film in the plastic sheet.

Then you are done. You have an invisible automotive AM/FM antenna.

You can see such an antenna by looking at the Aztec by GM. Also look at almost any recent model GM minivan. They have a very similar film in the windshield. Look very closely and you can see these parts. Ask the driver how he likes his radio reception.

GOOD LUCK!

John

Unknown

You have every right to be concerned about the legality of the window tint. If you have access to the Tennessee Code Annotated, read Section 55-9-107 regarding window tints. If you don't have access, let me know and I'll be glad to send you a copy. Basically, you can'r reduce visability through the windshield to less than 70%. However, all is not lost. Why not use the back window for the tint instead of the windshield? According to Tennessee Statute, with the exception of the windshield, light visability can be reduced to 35%.

Unknown

I located the metallic film, which reduces the infrared radiation by a considerable amount, thus making the car much cooler in the Summer. Also, I decided to put the film on the side glasses as well as the rear glass, and make the rear glass the antenna. So, with a radio-delete plate and no external antenna, most everyone will think it has no radio; but, it will have an AM/FM/Cassette radio (located in the glove box probably) with 6-CD Changer, optionally operated with a hand-held remote control.. Copper tape w/conductive adhesive is utilized to connect from the coax prong (soldered) to the film. The coax housing is tack welded to the body at some point to ground it.. Here is a portion of an email from a kind gentleman who shared this technology with me. "The conductive layer is sandwiched between two layers of the thin plastic.

The RF contact is capacitive. It doesn't matter about the glue (except
that it does not fall off.)

The real problem is that you (and I) do not know the size and shape of
the copper tape that would optimize the RF performance. Nor will we be
able to predict it. Sorry; ... it is trial and error. Theoretical
computations are too imperfect for your type of car.

But; approximately 1 1/2 inches wide by 4 inches long is likely ok.

You can see a bunch of drawings of this concept in the patent;
Go to the US Patent office web site and do a free search for:

Transparent Window Antenna,
Patent # 5,355,144, Oct. 11, 1994, Walton, Koontz, and Moran."

I hope this helps some of you guys who want a radio, but does not want to put a hole in a newly-painted fender; this is what I was hoping to avoid and it appears if I'll have the best of both worlds, as they say, with this hidden antenna!! Plus I'll have the benefit of reduced heat build-up in the car during the Summer. The metallic film installed costs $164 + tax.
I remain,

With best regards to all Hudson lover's

John